Oral Session Abstracts ORALS–MONDAY

105th Annual International Conference of the American Society for Horticultural Science Rosen Plaza Hotel, Orlando, Florida

Presenting authors are denoted by an asterisk (*)

Oral Session 1: Produce Quality and Health Properties 2:15–2:30 pm Ginsenosides Content in Different Morphological Monday, 21 July 2:00–3:30 pm Salon 8 Phenotypes of American Ginseng Roots Moderator: Bhimuanagouda Patil, [email protected] Samuel Obae* West Virginia University Morgantown WV; [email protected] 2:00–2:15 pm Todd West* Lime Juice—A Potential Source for Pancreatic Cancer West Virginia University Morgantown WV;[email protected] Prevention The content of six main ginsenosides, Rg1, Re, Rb1, Rc, Rb2, and Jaiprakash R Patil* Rd, were compared among three distinct morphological phenotypes of Vegetable & Fruit Improvement Center College Station TX; jrpatil_ American ginseng roots (Panax quinquefolium L.) namely, “man-like” [email protected] (ML), bulb or round (BLB), and stick (STK), using high-performance ChidambaraMurthy Kotamballi N liquid chromatography (HPLC). The chromatographic patterns among Vegetable & Fruit Improvement Center College Station TX; roots were similar, though they grouped into two chemotypes based [email protected] on the abundance of Rg1 and Re. The chemotypes were not particular to any phenotype, however, ML roots consistently exhibited low Guddadarangavvanahalli K. Jayaprakasha Rg1/high Re chemotype whereas BLB and STK roots exhibited both Vegetable & Fruit Improvement Center College Station TX; [email protected] low Rg1/high Re and high Rg1/low Re chemotypes. There was a significant difference in total ginsenoside content between ML roots Mahadev B. Chetti (2.19% 0.07%, w/w) and BLB or STK roots (1.86% 0.07%, 1.79% University of Agricultural Sciences Dharwad, Karnataka, India; 0.07%, n=72) respectively, however BLB and STK roots were not [email protected] significantly different. Total ginsenoside content within phenotypes Bhimanagouda S. Patil* increased with age (4 -10 years). Total content ranged from 0.94% to Vegetable & Fruit Improvement Center College Station TX; [email protected] 3.47% (w/w) for ML roots, 1.12% to 2.55% (w/w) for BLB roots, and 1.37% to 2.65% (w/w) for STK roots. Relative abundance of individual Limes (C. aurantifolia) are commonly used for fresh consumption in ginsenosides from highest to lowest was Rb1 > Re > Rc > Rg1 > Rd the form of traditional drink (Sharbat), juice, and pickles. Lime juice > Rb2. All individual ginsenoside content, except for Rc varied sig- was freeze-dried and subjected to extraction by various solvents such nificantly within root phenotypes and this can be attributed to genetic as CHCl3, acetone, MeOH, and MeOH:water by a Soxhlet- type ap- differences within populations. The results show that total ginsenoside paratus. These extracts and dried lime juice were analyzed by HPLC content in ML roots is obviously more compared to BLB and STK for the identification of bioactive compounds. The major flavonoids roots, which is helpful for quality grading and presents opportunities observed were hesperidin, neohesperidin, and rutin, while poncercin for improvement of American ginseng breeding efforts. was a minor compound. Furthermore, major limonoids identified were limonin, limoniod glucoside, and isolimonexic acid and obacunone. Specified Source(s) of Funding: Department, College, State and/or The potential of lime in cancer prevention was studied by using dried HATCH lime juice and extracts and subjected for proliferation inhibitory activity against pancreatic cancer cells (Panc-28) at different concentrations. The dried lime juice showed 76% inhibition of cells at 250 ppm whereas, 2:30–2:45 pm acetone, CHCl3, MeOH, and MeOH:water extracts showed 83%, A Fast and Uniform Absorbency Reading Time is 96%, 93%, and 91% inhibition, respectively, at same concentration in relation to untreated cells after 96 h of treatment. Interestingly, the Essential in Accurate Measurement of Pyruvic Acid juice concentrate and extract did not show cytotoxicity on normal cells When DNPH is Reacted to Undiluted Onion Juice (NIH 3T3) at similar doses. These results suggest that lime juice may Kil Sun Yoo* have potential benefits in cancer prevention. However, further in vivo Texas A&M University-VFIC College Station TX; [email protected] studies are required for confirmation of mode of action. The present research report is based upon work supported by the FY07-Federal Eun Jin Lee Initiative Designing Foods for Health through the Vegetable & Fruit Texas A&M University-VFIC College Station TX; s [email protected] Improvement Center, Grant No. TAES 06-118409. Bhimanagouda S. Patil Specified Source(s) of Funding: The present research report is based Texas A&M Univeristy-VFIC College Station TX; s [email protected] upon work supported by the FY07-Federal Initiative Designing Foods Onion pungency is measured by reading color intensities of wine for Health through the Vegetable & Fruit Improvement Center, Grant pink color after adding NaOH to the heated mixture of dinitrophenyl No. TAES 06-118409.

HORTSCIENCE, VOL. 43(4), JULY 2008 1077 hydrazine (DNPH) and onion juice. Though expected to be similar, 3:00–3:15 pm significant variation was reported among several modifications of Enhancement of Bioavailability of Flavonoids and the original SW method. In our own test, we have observed about 20% to 30% differences in pyruvic acid concentrations between our Limonoids from ‘Rio Red’ Grapefruit Juice by Piperin— automated method and a method using manual reading of absorbency. Evidence from In Vitro Studies To elucidate the source of the difference, we collected juices from 40 Guddadarangavvanahalli K. Jayaprakasha* onion bulbs of four colors and measured pyruvic acid concentrations Vegetable and Fruit Improvement center College Station TX; gkjp@tamu. by four different methods; 1) an automated system; 2) high perfor- edu mance liquid chromatography (HPLC); 3) manual spectrophotometric (SP); and 4) the original SW methods. The automated, HPLC, and Kotamballi N. Chidambara Murthy SW methods showed highly significant correlations and had similar Vegetable and Fruit Improvement center College Station TX; pungency levels. However, the SP method has estimated about 10% [email protected] to 30% less pyruvic acid than the automated and HPLC methods. The Bhimanagouda S. Patil absorbency reading of the undiluted juice samples in SP method was Texas A&M Univeristy-VFIC College Station TX; [email protected] decreasing very rapidly, as compared to the pyruvic acid standard, and resulted in lower estimation in the pyruvic cid concentration in the The bioavailability of phytochemicals has been of primary concern samples by about 20% to 30%. The difference became greater as the to claim the health benefits any products or food supplements. In reading time was extended. After all, by reading absorbency at around the current study, we report the impact of piperin, an alkaloid from 30 second after adding NaOH, we could obtain very similar pyruvic fruits of Piper longum, was tested for the bioavailability of Grapefruit acid concentrations between the automated and the SP methods. flavonoids and limonoids. ‘Rio Red’ grapefruit are widely consumed in the U.S. and juice has highly potential bioactive compounds such Specified Source(s) of Funding: Federal competitive Federal Program as naringin, limonin glucoside, limonin, and lycopene. ‘Rio-Red’ Name, Award Number: USDA Special grant (CSREES 2007, Desining grapefruit juice was mixed with piperin at different molar concentra- Foods for Health) tion and subjected for bioavailability study using in vitro gastric and pancreatic simulated models. Results have shown remarkable impact on the bioavailability of naringin, limonin, and DNAG as measured 2:45–3:00 pm by HPLC. The bioavailability of naringin was increased by 40.9% and Citrus Limonoids and Turmeric Curcuminoids 80% with addition of 100 and 250 microMolar piperin, respectively, Synergistically Inhibit Proliferation of Colon Cancer in juice. Similarly, the limonin content was enhanced by 18.5% and 40.2%. The results of the study clearly indicate the beneficial role of Cells piperin as a bioavailability enhancer, which remains a vital process Kotamballi N. Chidambara Murthy* in enhancing the bioaffecacy of these compounds. However, further Vegetable and Fruit Improvement Center ,College Station ,TX; studies are required in vivo models to analyze the enhancement of [email protected] efficacy of phytochemicals for various health benefits. The present research report is based upon work supported by the FY07-Federal Guddadarangavvanahalli K. Jayaprakasha Initiative Designing Foods for Health through the Vegetable & Fruit Vegetable and Fruit Improvement Center College Station ,TX; Improvement Center, Grant No. TAES 06-118409. [email protected], Specified Source(s) of Funding: The present research report is based Bhimanagouda S. Patil upon work supported by the FY07-Federal Initiative Designing Foods Texas A&M Univeristy-VFIC College Station TX; [email protected] for Health through the Vegetable & Fruit Improvement Center, Grant We have recently demonstrated the anticancer activity of highly oxygen- No. TAES 06-118409. ated triterpenes from citrus species. Current work reports investigation of synergistic effect of curcuminoids and limonoids for the inhibition human colon cancer cells. Limonoids, such as limonin and limonin 3:15–3:30 pm glucoside (LG), and curcuminoids were tested for the potential inhibi- Changes in Pungency and Flavor Precursor Compounds tion of colon cancer using cultured human adenocarcinoma (SW-480) cells individually and in combination. Limonin and LG inhibited 22% in Four Onion Cultivars by Applying Extra Sulfur cancer cells at 25 ppm concentration and curcumin exhibited up to 70% Nutrition as compared to control. At 25 ppm, the combination of curcumin with Eun Jin Lee* limonin and LG (1:1) has shown the enhancement of inhibition by 174.9 Texas A&M University-VFIC College Station TX; [email protected] and 309.2% respectively after 72 H with respect to limonoids. These results suggest that synergism between limonoids and curcumin and Kil Sun Yoo increased in activity was proportional to concentration of curcumin. Texas A&M University-VFIC College Station TX; [email protected] Furthermore, these compounds have shown evidence of inducing John Jifon apoptosis as evident from fragmentation pattern of DNA and significant Texas A&M University, Texas Agricultural Experiment Station Weslaco elevation of associated enzymes in comparison with untreated control TX; [email protected] cells. Understanding the mechanism of action of synergistic effect of both compounds and/or individual compounds for effective prevention Bhimanagouda S. Patil of cancer would be very useful for further clinical trials. The present Texas A&M Univeristy-VFIC College Station TX; [email protected] research report is based upon work supported by the FY07-Federal Initiative Designing Foods for Health through the Vegetable & Fruit Pungency and flavor precursor compounds in four onion cultivars Improvement Center, Grant No. TAES 06-118409. were measured to determine the effect of extra sulfur applications to the fields with sufficient S levels. Four onion cultivars, Cougar, Leg- Specified Source(s) of Funding: Federal competitive Federal Program end, Texas Early White (TEW), and TG 1015Y were grown in three Name, Award Number: FY07-Federal Initiative Designing Foods for different fields of the Rio Grande Valley area of Texas with varying Health through the Vegetable & Fruit Improvement Center, Grant No. levels of soil S from 30 to 235 ppm. Pyruvic acid, bulb weight, soluble TAES 06-118409. solids content (SSC), trans-(+)-S-1-propenyl-L-cysteine sulfoxide (1-PeCSO), methyl-(+)-S-sulfoxide (MCSO), methionine (Met), and cysteine (Cys) were measured. The pungency levels of onions were not linearly influenced by soil S levels in all cultivars, regardless of

1078 HORTSCIENCE, VOL. 43(4), JULY 2008 the fields (r2 = 0.009, n.s.). For examples, there were no differences 2:15–2:30 pm in pungency levels of onions grown at 30 ppm S or at 160 ppm S in Differential Expression of Transcription Factors ORALS–MONDAY ‘Legend’ and TEW onions. Pyruvic acid levels of each cultivar were in the order of ‘Legend’, ‘Cougar’, ‘TG 1015Y’, and TEW onions and Associated With Anthocyanin Pigmentation in Capsicum the levels were, 4.7, 4.8, 5.2, 7.8 µmol·m-1, respectively. The SSC was Gordon Lightbourn* poorly correlated and bulb fresh weight was negatively correlated with Virginia Polytechnic Institute and State University Blacksburg VA; gor- S levels. We are also investigating 1-PeCSO, MCSO, free amino acids [email protected] of Met, and Cys used in the flavor compound biosynthetic pathway. Brenda Winkel Since no/poor correlations were found between pungency and soil S concentrations, we concluded that pungency of onions cannot be Virginia Polytechnic Institute and State University Blacksburg VA; significantly changed by applying extra S nutrition in a commercial [email protected] field containing sufficient levels of S (30 ppm in this study) or irrigated Robert Griesbach with water with high S content. Rather, choosing onion cultivars with USDA, ARS, Floral and Nursery Plants Research Unit, U.S. National low pungency is believed to be a key factor to produce sweet onions Arboretum Beltsville MD; [email protected] in the Texas field conditions. John Stommel* Specified Source(s) of Funding: USDA special grant (CSREES 2007, USDA, ARS, Genetic Improvement of Fruits and Vegetables Laboratory, Desining Foods for Health) Plant Sciences Institute Beltsville MD; [email protected] Anthocyanin structural gene transcription requires the expression of at least one member of each of three transcription factor families - MYCA, Oral Session 2: Biotechnology 1 MYBA and WD40. These transcription factors form a complex that binds to structural gene promoters, thereby modulating gene expres- Monday, 21 July 2:00–3:45 pm Salon 7 sion. Capsicum annuum displays a wide spectrum of tissue-specific Moderator: Carole Bassett, [email protected] anthocyanin pigmentation, making it a useful model for the study of anthocyanin accumulation. In order to determine the genetic basis for tissue-specific pigmentation, we evaluated the expression of anthocyanin 2:00–2:15 pm biosynthetic (Chs, Dfr, Ans) and regulatory (MycA, MybA, Wd40) genes Apple Root Expressed Sequence Tags (ESTs) Responding in flower, fruit and foliar tissue from pigmented and non-pigmented to Water Deficit genotypes. No differences were observed in expression of the Wd40 gene among these tissues. However, in all cases, biosynthetic gene Carole Bassett* transcript levels were considerably higher in anthocyanin pigmented USDA Kearneysville WV; [email protected] tissue than in non-pigmented tissues. MybA and MycA transcript lev- Michael Wisniewski els were also substantially higher in anthocyanin pigmented fruit and USDA Kearneysville WV; [email protected] floral tissues. Sequence analysis of the products of 5’ and/or 3’ RACE experiments indicates that the MybA and MycA transcripts in these Angela Baldo tissues are each derived from at least two different genes. In contrast USDA Geneva NY; [email protected] to the situation in flowers and fruit, differential expression of MybA and MycA was not observed in foliar tissue, suggesting that different Schuyler Korban mechanisms contribute to the regulation of anthocyanin biosynthesis University of Illinois at Urbana-Champaign Urbana IL; [email protected] in different parts of the Capsicum plant. Ksenija Gasic Specified Source(s) of Funding: Department, College, State and/or Clemson University Clemson SC; [email protected] HATCH Robert Farrell, Jr. Pennsylvania State University York PA; [email protected] 2:30–2:45 pm Water availability is frequently the most critical factor limiting plant growth and survival. For crops such as cereals and herbaceous annuals, Proteomic Analysis of Flower Senescence breeding and/or selecting lines with improved water use efficiency or Michelle Jones* drought resistance has been a viable option. However, for slow growing The Ohio State University Wooster OH; [email protected] perennials and woody plants, this approach is more problematic. One strategy that can aid breeding programs in selecting lines improved for Laura Chapin traits that are either difficult or cumbersome to measure is to develop The Ohio State University Wooster OH; [email protected] markers closely linked to the traits of interest. Candidate gene mark- Shuangyi Bai ers that are likely to be related to the desirable trait could be used to The Ohio State University Wooster OH; [email protected] identify genes associated with drought resistance. To develop a series of candidate ESTs for mapping water use efficiency and drought resis- Senescence represents the last stage of flower development, ultimately tance in apple (Malus domestica), we conducted preliminary studies culminating in the death of the corolla. The senescence program is to isolate ESTs responsive to drought in ‘Royal Gala’, a commercially regulated by coordinated changes in gene and protein expression, and important cultivar. In this study we used suppression subtractive hy- the later stages of senescence share many characteristics of programmed bridization (SSH) to identify genes up- and down-regulated in roots cell death. In petunia flowers, pollination induces ethylene production of plants exposed to two weeks of severe water restrictions (45% soil and accelerates corolla senescence. To identify components of the water saturation). We identified approximately 30 genes that were senescence program in petunia corollas, we have investigated protein up-regulated in response to water deficit and about half that number expression patterns at 0, 24, 48, and 72 h after flower opening and at that were down-regulated. We compared these results to a similar 24, 48, and 72 h after pollination. Corolla wilting is the first visual approach taken previously to develop EST libraries from root, bark symptom of senescence, and corollas from pollinated flowers were and leaf material exposed to water deficit conditions. Combining the wilted by 48 h. Total proteins from Petunia × hybrida‘Mitchell Diploid’ results of both approaches has allowed us to expand the number of corollas were separated by two-dimensional gel electrophoresis, and ESTs that respond to water deficit in apple. proteins that were up- or down-regulated by two fold in pollinated petals were identified using PDQuest image analysis software (BioRad). Electrospray ionization-tandem mass spectrometry (ESI-MS/MS) was

HORTSCIENCE, VOL. 43(4), JULY 2008 1079 then used to determine the identity of 133 differentially expressed pro- Donglin Zhang* teins. A putative identification has been assigned to greater than 90% University of Maine Orono ME; [email protected] of the proteins by searching the NCBI nonredundant protein database and a translated petunia database developed at OSU. The programmed Jiao Hu senescence of flower petals allows the plant to remobilize nutrients Central South University of Forestry and Technology Changsha China; from dying to developing tissues. In support of this recycling func- [email protected] tion most of the senescence up-regulated proteins were found to be Deyi Yuan involved in catabolic processes including the degradation of nucleic Central South University of Forestry and Technology Changsha China; acids, proteins, lipids and cell walls. Some of the genes encoding [email protected] senescence up-regulated proteins have been identified from Petunia EST database searches (TIGR and SGN) and others have been cloned Feng Zou using degenerate primers and RT-PCR. The functional analysis of Central South University of Forestry and Technology Changsha, China; selected senescence up-regulated proteins using virus-induced gene [email protected] silencing (VIGS) will be presented. Chinese sand pear is closely related to Japanese pear. Both of them Specified Source(s) of Funding: D.C. Kiplinger Endowment Indus- belong to [Pyrus pyrifolia (Burm.) Nak.] that exhibits gametophytic try/Association Program: Fred °C Gloeckner Foundation; USDA self-incompatibility. Knowledge of self-incompatibility genotypes Floriculture and Nursery Research Initiative (S-genotypes) of cultivars is essential for improving pear production and cross-breeding. Recently, new S-alleles in Chinese sand pear were discovered and the JP-PCR-RFLP (Japanese pear-PCR-restriction 2:45–3:00 pm fragment length polymorphism) system did not work for Chinese sand pear cultivars S-genotyping. We cloned eight cDNAs of S-RN- Glutaredoxin-mediated Oxidative Stress Protection to ases from Stylar RNA of Chinese sand pear cultivars by RT-PCR and Improve Stress Tolerance in Vegetable Crops RACE and two (S15 and S16) of them were new S-RNase alleles. Sabarinath Sundaram Based on sequence analysis, a novel CSP-PCR-RFLP (Chinese sand University of Florida, Gainesville; pksnath@ufl.edu pear-PCR-RFLP) system was established that consists of genomic PCR amplification with a pair of consensus primers followed by Shan Wu digestion of the PCR fragments with S-RNase allele specific restric- University of Florida, Gainesville; wus@ufl.edu tion endonucleases. Using this system, a total of 13 S-RNase alleles Piyasa Ghosh in Chinese sand pear were efficiently discriminated and 15 cultivars were rapidly and accurately S-genotyped. The CSP-PCR-RFLP will University of Florida, Gainesville; [email protected] be applied for further studies of Chinese sand pear. These results will Bala Rathinasabapathi* ensure the higher and stable yields in the orchards and a more efficient University of Florida, Gainesville; brath@ufl.edu breeding program. Glutaredoxins are glutathione-dependent oxidoreductases known to Specified Source(s) of Funding: Department, College, State and/or protect cellular proteins against damage by oxidative stress. Plants HATCH the Key Project of State Forestry Administration, P. R. China contain many glutaredoxins whose functions are not well understood. (2006-12). We analyzed expression profiles of glutaredoxins in the genome of Arabidopsis thaliana using publicly-available Microarray data. This study identified that 11 out of 33 glutaredoxins are modulated at the 3:15–3:30 pm transcriptional level by one or more abiotic stress factors, implying Probing the Vitis Genome—Opportunities and Pitfalls roles in stress tolerance. To test whether transgenic expression of a glutaredoxin could be a tool to improve stress tolerance, a fern cDNA Zhijian Li* for a glutaredoxin PvGrx5, previously implicated in arsenic resistance, Univeristy of Florida/IFAS Apopka FL; zjli@ufl.edu was overexpressed in Arabidopsis thaliana. Homozygous lines express- Sadanand Dhekney ing PvGrx5 were significantly more tolerant than vector control lines University of Florida/IFAS Apopka FL; sadanand@ufl.edu when container-grown plants were stressed at supraoptimal temperatures. Compared to vector control lines, PvGrx5-transgenic lines were Dennis Gray characterized by significantly greater growth and photosynthesis under University of Florida/IFAS Apopka FL; djg@ufl.edu stress conditions and significantly less tissue damage as measured by ion leakage and the amount of oxidized proteins. Our work indicates Over the past decade an enormous number of ESTs and genomic for the first time the potential of using genes for plant glutaredoxins for sequences of Vitis have been made available in various databases and improving vegetable crops for high temperature stress tolerance. the Pinot Noir genome was sequenced in 2007. This data provides vital information for analysis of genes and proteins associated with Specified Source(s) of Funding: Department, College, State and/or important biological functions and processes, further enhancing the HATCH Federal competitive Horticultural Sciences Department, IFAS, efficacy of genetic manipulation of grapevine. Using several sequence Univ of Florida and USDA-TSTAR grant 2005-34135-15898. analysis tools, we have identified genes and their products related to disease resistance and other agronomic traits. For example, up to 438 putative translated sequences harboring the NBS-LRR domain similar 3:00–3:15 pm to that found in the Run1 disease resistance gene of grape have been Clone S-RNase cDNAs and Establish CSP-PCR-RFLP identified. Phylogenetic analysis has established the evolutionary profile of such gene superfamilies in grape. In addition, new found System for Cultivars S-genotyping in Chinese Sand Pear genomics data has revealed that a unique gene, previously cloned [Pyrus pyrifolia (Burm.) Nak.] and suggested to play a vital role in powdery mildew resistance in a Lin Zhang wild Vitis species, actually exists in the Vitis vinifera genome as well. Central South University of Forestry and Technology Changsha China Based on SCAR markers, candidate genes closely associated with [email protected] the seedless trait have also been identified. Analysis of their complex genomic structure suggests highly regulated control of gene expres- Xiaofeng Tan* sion. The implication of sequence-based genomics analysis and the Central South University of Forestry and Technology Changsha , China; effectiveness of current strategies for the molecular improvement of [email protected] grapevine will be discussed.

1080 HORTSCIENCE, VOL. 43(4), JULY 2008 Specified Source(s) of Funding: Federal competitive -Department, Travella Free College, State and/or HATCH FDACS Viticulture Trust Fund North Carolina A&T Greensboro NC; [email protected] ORALS–MONDAY Community gardening has been used as the perfect vehicle for integrated Extension programming in North Carolina. Extension Specialists in 3:30–3:45 pm Horticulture, Family Consumer Science, 4-H Youth Development, Deep Sequencing of Fragaria—Transcriptome Content Program Evaluation, Community Development, and Environmental and Interspecific Comparisons and Natural Resources worked together to develop and present train- Maureen Clancy ings across the state for county agents, master gardener volunteers, and community leaders. Training included how to develop successful University of Florida, Gainesville; maclancy@ufl.edu community gardens as well as how to use to gardens to accomplish Mishra Viplav specific goals related to health and nutrition education, neighborhood University of Florida, Gainesville; [email protected] revitalization, environmental stewardship, youth development, and much more. In addition, participants were trained in specific skills Thomas Davis in program evaluation and were provided with survey tools to assess University of New Hampshire Durham NH; [email protected] changes in knowledge, skills, and behavior. Kevin Folta* Specified Source(s) of Funding: Department, College, State and/or University of Florida, Gainesville; [email protected]fl.edu HATCH A 454-based sequencing approach has been employed to assess the expressed gene content of strawberry (Fragaria spp.) A barcoding approach allowed deep sequencing of expressed sequences from 4:15–4:30 pm various tissues in response to a series of treatments. The same tissues Louisiana Yards and Neighborhoods were pooled from separate plants exposed to a discrete treatment. Treatments included darkness, heat, cold, far-red light, gibberellin Bobby Fletcher treatment, spider mites, mechanical damage, in addition to 20 other LSU AgCenter–Lafourche Parish Thibodaux LA; bhfl[email protected] treatments. Tissue was harvested at 1- and 24-h time points following Allen Owings* treatment (in addition to others) to identify primary and late response LSU AgCenter–Hammond Research Station Hammond LA; transcripts in these processes. Entire plants from Fragaria vesca and [email protected] Fragaria iinumae (putative subgenome donors) were included to assess the allelic variation between these species and the octoploid. The The LSU AgCenter has recently initiated a Louisiana Yards and results of this endeavor allow accounting of allele-specific expression Neighborhoods (LYN) program modeled after the successful Florida in various plant tissues and developmental contexts, while greatly Yards and Neighborhoods program developed by the University of increasing the EST resources in the genus. Florida. The focus of this program is to encourage LSU AgCenter home ground clientele to create and maintain landscapes in ways that Specified Source(s) of Funding: Federal competitive National Science minimize environmental impact. This will include areas such as water Foundation, Plant Genome Research Program quality, irrigation conservation, reduction of stormwater runoff, and decreasing nonpoint source pollution of surface water, along with enhancing desirable wildlife habitats and creating functional, attractive landscapes. The program, which is implemented through parish Oral Session 3: Consumer Horticulture/Master Gardeners LSU AgCenter extension agents, primarily in the horticulture field, Monday, 21 July 4:00–5:00 pm Salon 8 with support from Louisiana Master Gardener volunteers, provides education and outreach activities in the community to help residents Moderator: Lucy Bradley, [email protected] reduce pollution, conserve water and enhance their environment by improving home and landscape management. This integrated approach 4:00–4:15 pm to landscaping emphasizes seven interrelated principles: 1) right plant for the right place; 2) watering efficiently; 3) maximizing mulch and Community Gardening: Integrated Extension recycled yard waste; 4) fertilizing effectively; 5) managing yard pests; Programming at Its Best 6) protecting surface waters and wetlands; and 7) providing for benefi- Lucy Bradley* cial wildlife habitat. A LYN handbook and accompanying powerpoint North Carolina State University Raleigh NC; [email protected] presentations have been developed and Master Gardeners in Lafourche, Terrebonne, and St. Mary parishes have completed an initial “train the Koralalage Sunil Upali Jayaratne trainer” on program aspects. The goal is for this pilot program to be North Carolina State University Raleigh NC; [email protected] implemented statewide using Master Gardener volunteers to deliver Keith Baldwin educational programs with support from salaried faculty. North Carolina A&T State University Greensboro NC; [email protected] Specified Source(s) of Funding: Private (Association, Foundation, Susan Jakes Industry) North Carolina State University Raleigh NC; [email protected] Michelle Ely 4:30–4:45 pm North Carolina A&T Greensboro NC; [email protected] Statewide Master Gardener Intranet Karen Neill Lucy Bradley* North Carolina State University Greensboro NC; [email protected] NC State University Raleigh NC; [email protected] Liz Driscoll A statewide, county specific, password protected, Master Gardener North Carolina State University Raleigh NC; [email protected] Intranet was established to assist county horticultural agents with man- Stephanie Tatum aging Master Gardeners. The on-line searchable database with contact North CarolinaA&T University Greensboro NC; [email protected] information and volunteer profiles makes staying connected automatic. The web-based scheduling system allows users to request volunteer assistance, as well as to sign up for volunteer opportunities. On-line

HORTSCIENCE, VOL. 43(4), JULY 2008 1081 tracking of volunteer and continuing education credits can be done by information on horticultural technology and science and provides volunteers. Web-based calendar of events contains detailed information significant information on subjects such as the history of technology, about upcoming activities. In addition, each area of the program has crop evolution, lost traits, and crop dispersal. designated web space to share information, promote activities, and to provide volunteers with the tools they need for success. Specified Source(s) of Funding: Private (Association, Foundation, Industry) Lillium Goldman Foundation Specified Source(s) of Funding: Department, College, State and/or HATCH 4:15–4:30 pm Differential Antioxidant Capacity Among Twelve Potato 4:45–5:00 pm Cultivars Estimating U.S. Consumers’ Choice of Floral Retail Andre Piccolomini* Outlets McGill University Ste-Anne-de-Bellevue QC Canada; Chengyan Yue* [email protected] University of Minnesota St. Paul MN; [email protected] Stan Kubow Bridget Behe McGill University Ste-Anne-de-Bellevue QC Canada; Michigan State University, East Lansing; [email protected] [email protected] Competition among floral retailers has changed the retail landscape Danielle Donnelly* while giving consumers more choices in locations for purchase. Con- McGill University Ste-Anne-de-Bellevue QC Canada; sumer panel data collected by the American Floral Endowment from [email protected] 1992 to 2005 were used to evaluate consumers’ choice of different Arunachalam Annamalai floral retail outlets among box stores (BS), traditional free-standing floral outlets (TF), general retailer (GR), other stores (OS), and Karunya University Tamil Nadu, India; [email protected] direct-to-consumer (DC) channels. Since 1992, market share and Priscila Riciardi percentage of transactions decreased through TF, but increased for McGill University Ste Anne de Bellevue QC Canada; BS. Mean expenditure per transaction in TF was higher than in BS [email protected] and GR. Consumers who made floral gift purchases were more likely to patronize TF, but those who bought floral products for themselves Atef Nassar were more likely purchase from BS. Consumers patronizing TF or McGill University Ste Anne de Bellevue QC Canada; DC were more likely to buy arranged flowers rather than unarranged [email protected] flowers. Consumers who purchased foliage plants and outdoor bed- Kebba Sabally ding or garden plants were more likely to buy them from BS. Reasons McGill University Ste-Anne-de-Bellevue QC Canada; consumers who choose BS and GR cited for making the purchase were [email protected] higher for convenience and price while consumers who went to TR and DC cited delivery, reputation, and service. Consumers were more Potatoes represent over 40% of all vegetables consumed in Canada and likely to buy gifts from TF instead of BS. Wealthier consumers tend may be considered as functional foods due to their high antioxidant to patronize TF instead of BS. Not surprisingly, we found that U.S. capacity and phenolic content. The goal of this study was to identify consumers’ choices of retail venues differed across different regions. the antioxidant activity and phenolic content of twelve important po- Some retailers may have a competitive advantage in some regions of the tato cultivars grown in Canada or Europe. Twelve cultivars including country that they may be able to copy or duplicate in other geographic Atlantic, Gold Rush, Green Mountain, Kennebec, Norland, Onaway, areas. Our findings have important market implications. Red Pontiac, Russet Burbank, Sebago, Shepody, Superior, and Yukon Gold were tested for antioxidant activity and phenolics (mg/100g dry matter). In vitro antioxidant assays included FRAP (Ferric Reduc- ing Antioxidant Power) and DPPH (1,1-diphenyl-2-picrylhydrazyl) Oral Session 4: expressed as ascorbic acid equivalents/g dry matter). A HPLC assay tested for ascorbic acid and the phenolics including chlorogenic acid, Culture & Management: Vegetable Crops 1 ferulic acid, caffeic acid, and rutin. Data were analyzed using one-way Monday, 21 July 4:00–6:00 pm Salon 11 ANOVA and significance differences among means was determined Moderator: Carol Miles, [email protected] by Tukeys test at P < 0.05. Relative to other cultivars, Sebago had the highest FRAP activity (0.27 ± 0.005 mg/g) and Superior (0.39 ± 0.009 mg/g) had the highest DPPH activity (P < 0.05). Chlorogenic 4:00–4:15 pm acid (CA), which is responsible for undesirable appearance and sensory What did the Emperor Tiberius Grow in His qualities by causing the bluish-grey discoloration of cooked potatoes Greenhouse? following air exposure, varied considerably among cultivars (ranging from 15.4% to 91.9% of total phenolic content, mean = 50.1%). Gold Jules Janick* Rush had 2-6 fold greater content of CA (58.9 ± 9.4 mg/100g) than Purdue West Lafayette IN; [email protected] all other cultivars (P < 0.05), but had up to a 5-fold lower content of other phenolics (5.2 ± 9.4 mg/100g) (P < 0.05). Onaway and Norland According to Pliny the Elder, the Roman author of Historia Naturalis, had a 2-6 fold greater content of other phenolics relative to most other the Emperor Tiberius (42 BCE to 37 CE) had a remarkable partiality cultivars, (19.7 ± 1.6 and 13.8 ± 0.6 mg/100g, respectively) but had for cucumis and there was never a day on which he was not supplied the lowest CA content (8.4 ± 0.6 and 2.5 ± 0.4 mg/100g, respectively) with it, as his kitchen gardeners had cucumis beds mounted on wheels (P < 0.05). The results underline the importance of cultivar selection which they moved out into the sun and then on wintry days withdrew toward the greatest antioxidant activity and optimal phytochemical under the cover of frames glazed with transparent stone (mica). This profile for both improved human health and consumer acceptance. remarkable comment, almost 2000 years old, is the first mention of greenhouses (called a specularium). The translation of cucumis as Specified Source(s) of Funding: Department, College, State and/or cucumber is a mistranslation that can be proved by a combination HATCH Universidad de Colima Facultad de Ciencias Biologicas y of literary exegesis and an investigation of ancient images. Works Agropecuarias Fondo Ramon Alvarez-Buylla de Aldana of art from antiquity to the present constitute an alternate source of

1082 HORTSCIENCE, VOL. 43(4), JULY 2008 4:30–4:45 pm count parameters were chosen for neural network modeling. A back propagated feed forward artiﬁcial neural network (AFNN) was devel-

A Greenhouse Study of Grafting Vigor in Tomato ORALS–MONDAY oped by training with 216 samples. The validation of the network was (Lycopersicon esculentum Mill.) done with 24 samples. The multi-layered, perceptron-based network Xin Zhao* had 4 inputs nodes, 8 and 6 hidden nodes, and 2 output nodes. The University of Florida, Gainesville; zxin@ufl.edu network converged after 20,000 cycles as the correlation coefficient and mean squared error peaked 0.91 and 2.26 × 10-2 for crop yields. Eric Simonne Sensitivity analyses on each of the input parameters were conducted University of Florida, Gainesville; esimonne@ufl.edu and the results are discussed. Jeremy Edwards Specified Source(s) of Funding: Federal competitive The present re- University of Florida Wimauma FL; edwardsjd@ufl.edu search is supported by the FY07-Federal Initiative Designing Foods John Scott for Health through the Vegetable & Fruit Improvement Center, Grant University of Florida Wimauma FL; jwsc@ufl.edu No. TAES 06-118409. In addition to improvement of disease resistance, the grafting technique has shown the potential for yield increase in vegetables when 5:00–5:15 pm there is little disease pressure. A greenhouse pot study was carried Evaluating Dry Bean Varieties for Fresh Shell Bean out to investigate the effect of grafting on growth and yield of tomato (Lycopersicon esculentum Mill.) in the absence of root pathogens. Production ‘Florida-47’, a popular tomato variety grown in Florida while sus- Carol Miles* ceptible to root-knot nematode, Fusarium wilt race 3, and Fusarium Washington State University Mt Vernon WA; [email protected] crown rot, was grafted onto a commercially available disease resistant rootstock ‘Maxifort’. Grafting was conducted at the 5-6 leaf stage Dry bean (Phaseolus vulgaris) is a common large-scale commod- using the splice method. The graft union was completely healed ity crop in the U.S. and numerous varieties are also well suited for within 5-7 days with an average survival rate above 90%. Ten days fresh shell bean production, a niche market high-value crop common after grafting, grafted and self-rooted tomatoes were transplanted into throughout southern Europe, Africa, and South and Central America. pots and arranged in a randomized complete-block design with four We evaluated 34 dry bean varieties for suitability for fresh shell bean replications. All the suckers below the first fruit cluster were removed production in a RCBD study with four replications in 2006 and 2007. during the plant growth. Initially, the healing process tended to hinder Desirable characteristics include large bean size, large pod size, and the plant growth and development as indicated by the delay of the large number of beans per pod. Cannellini, Flageolet and Cranberry first flowering date in the grafted treatment. The self-rooted plants are preferred types, however, color-patterned and pink shell beans remained significantly taller than the grafted ones until about 6 weeks may also be desirable. In our study, entries differed significantly in all after transplanting, when the plant height of the two treatments became measured parameters both years. Varieties with the largest 100-bean similar. In contrast, grafted tomatoes had a larger stem diameter than weight were in the Cranberry market class both years, PS01-207-2-B3, the self-rooted treatment and the difference was more evident as the Tongue of Fire, and PS01-203-2-B3 in 2006, and USCR-15, Supremo, plants grew. Although the tomato yield from the early harvest was lower and UI-686 in 2007. Flagrano and Flaro had the smallest 100-bean in the grafted treatment, the prominent grafting vigor was revealed weight both years. Supremo had the greatest pod length in 2006 and in mid and late harvests. The Assessment of fruit quality parameters Cannellini in 2007. Belneb-RR-1 and White Marrow had the largest demonstrated that the overall fruit quality was not adversely affected number of beans per pod in 2006, while White Marrow and Flagrano by grafting with ‘Maxifort’ as the rootstock. and Flaro had the largest in 2007. Cannellini, Vermont Cranberry, White Marrow and Flaro produced the greatest yield (whole pods) Specified Source(s) of Funding: Department, College, State and/or in 2006, while USCR-15, UI-686, Thort and Vermont Cranberry pro- HATCH University of Florida IFAS Research Innovation Fund duced the greatest yield in 2007. Supremo, Jacob’s Cattle and Black Calypso produced the lowest yield in 2006, while Beryl and Red Hawk produced the lowest yield in 2007. Matterhorn, PS01-207-2-b3, Red 4:45–5:00 pm Hawk, Black Calypso, and Jacob’s Cattle were the earliest to mature in 2006, while Cannellini, ABL6, and French Flageolet Flagrano-Flaro Agroclimatology-based, Cultivar-specific Artificial Neural were the earliest to mature in 2007. These results indicate that many Network Model for Predicting Diced Carrot Yields varieties with desirable shell bean characteristics are productive in Arumugam Thiagarajan* the Pacific Northwest. Varieties should be selected based on desirable Nova Scotia Agricultural College Truro NS Canada [email protected] market characteristics in addition to high yield potential. Rajasekaran R. Lada Specified Source(s) of Funding: Federal competitive USAID Bean/ Nova Scotia Agricultural College Truro NS Canada [email protected] Cowpea Collaborative Research Support Program Federal Program Name, Award Number: USAID Bean/Cowpea Collaborative Research Azure D. Adams Support Program Nova Scotia Agricultural College Truro NS Canada [email protected]

Yield is a consequence of complex interactions between genotypes, 5:15–5:30 pm environment, input and management factors. In industrial horticulture, yield and quality prediction is critical for production, process and Optimum Plot Size and Number of Replications for market planning, and harvest decision-making. This research presents Watermelon Yield Trials an artiﬁcial neural network model for carrot root and leaf yields in George Boyhan* response to cultivar and weather parameters. A ﬁeld experiment was University of Georgia Statesboro GA; [email protected] conducted in 2006 with RCC and Euforo cultivars seeded at 6, 9, 12, 16, and 20 seeds/ft in three replicates. Fresh root yield and leaf growth Randy Hill were monitored at six different phonological development of the crop University of Georgia Lyons GA; [email protected] from emergence to full maturity. Along with cumulative degree days Denny Thigpen (CDD), all of the monitored weather parameters were subjected to correlation analysis using SAS back elimination procedure. All weather University of Georgia Statesboro GA; [email protected] 2 parameters showed strong correlation (r > 0.90) with CDD except Three different methods were used to determine optimum plot size cumulative rainfall (CR). Consequently CR, CDD, variety and stand for watermelon yield. With a basic unit size of 3.34 m2, plotting the

HORTSCIENCE, VOL. 43(4), JULY 2008 1083 coefficient of variation (y-axis) against the basic units (x-axis), the on commonly grown ‘Petite Perfection’ and ‘Vanessa’ cultivars at the maximum curvature of the hyperbola occurred at approximately 7-10 Cunningham Research Station, Kinston, NC. Transplants were sown 13 basic units. Computing Bartlett’s chi-square for homogenity of vari- Apr. 2006, and grown in the greenhouse in Raleigh, NC. Planting was ance for different plot sizes, no differences occurred between plot 16 May into black polyethylene mulch with drip irrigation. Row centers size with 7 basic units up to a plot size with 35 basic units suggesting were 3.1 m apart. Plots were arranged in a randomized complete-block that 7 basic units would be sufficient for analysis. Using Hathaway’s design with 3 replications. Hill spacing treatments were 15, 31, and 46 method for determining optimum plot size and number of replica- cm and contained either 1 or 2 plants. Plant populations ranged between tions with a threshold of a true difference of 20% of the mean or less 7,173 to 43,037 plants per ha. Cumulatively over 4 harvests, planting combinations of 14 basic units and 3 replications, 10 basic units and density influenced total fruit production which ranged from 33,100 to 4 replications, or 7 basic units and 5 replications would fit the criteria. 65,000 fruit per ha. However, between 19% and 47% of the total fruit True differences of 16%, 17%, and 20% of the mean were calculated were not marketable due to cultivar and planting density. Total market- for each, respectively. able fruit production per ha ranged from 20,700 to 36,300. ‘Vanessa’ averaged 31,100 marketable fruit per ha and ‘Petite Perfection’ 29,400 Specified Source(s) of Funding: Department, College, State and/or fruit across the planting density treatments. Total yields were increased HATCH with 2 vs. 1 plant per hill; however, total marketable yields were not increased. For ‘Petite Perfection’, marketable yields peaked when 1 5:30–5:45 pm plant per hill was planted at the 31 cm between hill spacing, while yield for ‘Vanessa’ increased as spacing between plants decreased (46 Impact of 1-MCP on Fruit Set and Yield of Seedless to 15 cm). The closest in-row spacing of ‘Petite Perfection’ resulted Watermelon in more fruit that were too small in size with either 1 or 2 plants per Shinsuke Agehara* hill (30% or 42%, respectively) than the wider spacings. Average fruit Texas AgriLife Reserach, Texas A&M System Uvalde TX; size of ‘Vanessa’ was more than ‘Petite Perfection’. Planting density [email protected] and arrangement should be adjusted to meet size demand depending on cultivar for the mini watermelon market. Daniel Leskovar* Texas AgriLife Research, Vegetable & Fruit Improvement Center, Texas Specified Source(s) of Funding: Department, College, State and/or A&M System Uvalde TX; [email protected] HATCH Watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] yield is often limited by its ability to sustain a limited number of fruits on the vine. Oral Session 5: Controlled Environment 1 The objective of this study was to determine the effects of pre-harvest spray application of 1-MCP (1-methylcyclopropane, SmartFresh ), an Monday, 21 July 4:00–6:00 pm Salon 7 inhibitor of ethylene binding sites, on fruit set, marketable yield, and Moderator: Cary Mitchell, [email protected] fruit quality of seedless watermelon. Seedlings (triploid cv. SS 7187 and the diploid pollinator cv. SF 800) were transplanted on an Uvalde silty clay loam on Apr. 8, 2005, and Apr. 27, 2006. Three 1-MCP rates 4:00–4:15 pm (0.5, 1, and 10 g·ha-1 a.i. in 2005 and 5, 10, or 25 g·ha-1 a.i. in 2006) Caribbean Pepper Production under Protecting were applied at three timings [(1, 7 and 1+7 days after flowering (DAF) Structures in the U.S. Virgin Islands in 2005 and 7, 14, or 7+14 DAF in 2006)]. The control 0 g·ha-1 a.i. was sprayed at either 1+7 or 7+14 DAF in 2005 and 2006, respectively. Ramon Arancibia* Sequential female flower and fruit counts were made in each season. Mississippi State University-MAFES Pontotoc MS; [email protected] Harvests began June 27, 2005, and July 6, 2006. The number of female Thomas Zimmerman* flowers slightly increased by 1-MCP 10 g/ha-1 a.i. at 15 DAF in 2005. University of the Virgin Islands Kingshill, St. Croix VI; [email protected] In 2006, spray of 1-MCP at 25 g·ha-1 a.i. increased fruit number per plant by 40% over the control when measured 25 DAF, being the highest Two studies to evaluate the effect of protected agriculture on virus increase when applied 7+14 DAF. Similarly, across all 1-MCP rates the incidence and production of Caribbean peppers were conducted in the average number of marketable fruits per plant increased by 27%, while U.S. Virgin Islands. In the first experiment, spun-bonded rowcover was a single application (7 or 14 DAF) of 10 or 25 g·ha-1 a.i. increased total used as insect barrier in the initial growing stage (2 months) of Puerto marketable yield by 17% to 36% as compared to the control. Overall, Rican sweet pepper. Peppers were not sprayed to allow for insect fruit soluble solid content was slightly improved by 1-MCP in both infestation. At rowcover removal, protected plants were taller than seasons. Under our environmental conditions, pre-harvest application uncovered plants and symptoms of virus infection were observed in of 1-MCP appeared effective to increase fruit number and marketable the uncovered plots, but not in the covered plots. Plants with symptoms yield in triploid watermelon. were positive to potyviruses as detected by ELISA (Agdia). Samples from the covered plots were negative. Virus incidence increased in Specified Source(s) of Funding: Department, College, State and/or time, and after 6 months, all tested plants from both treatments were HATCH Private (Association, Foundation, Industry) Industry/Associa- positive to potyviruses. Weekly harvest started 4.5 months after planting tion Program Name, Award Number: AgroFresh and continued for 9 weeks. Yield in the first four harvests was higher in the covered plots. Similarly, fruits were larger in the covered plots for the first two harvests only. Fruit size decreased gradually through 5:45–6:00 pm the harvest period reflecting the high incidence of virus infections. In Yield Response to Planting Density Varies among Mini the second experiment, potted habanero and Puerto Rican sweet pep- Watermelon Cultivars per were grown protected from insects in a screen-house (12? × 20?) Brad Thompson enclosed with a net mesh 81 (Green-Tek). Control plants were grown outside the screen-house. Tobacco etch virus and pepper mottle virus North Carolina State University Raleigh NC; [email protected] were detected after 4 months in some unprotected plants with symptoms, Jonathan Schultheis* but not in protected plants. Yield of protected habanero peppers was North Carolina State University Raleigh NC; [email protected] 1.9 times the unprotected yield. Puerto Rican sweet pepper, however did not set fruit either in the screen-house or outside suggesting that Market size range for mini watermelon is specific. Fruits are marketed the potting system may not be adequate for this variety in the U.S. when they weigh from 1.4 to 3.2 kg. Larger fruits usually fit into the Virgin Islands. “ice box” size category. To maximize yields of marketable size fruit for the mini watermelon market, a planting density study was conducted Specified Source(s) of Funding: Federal competitive

1084 HORTSCIENCE, VOL. 43(4), JULY 2008 4:15–4:30 pm at pressures generally between 1000-1500 psi. Low-pressure misting systems inject larger water droplets at pressures generally below 100 Horticultural and Postharvest Potential of Producing ORALS–MONDAY psi. Ventilation is required for the fog system or it will lose its capacity Florida Strawberry Cultivars under High Tunnels to evaporate, causing water droplets to land on plants and puddles to Teresa Salame* form on the ground. The type of evaporative cooling system and how University of Florida Wimauma FL; tsalame@ufl.edu it is designed will greatly affect both performance and water use. The greenhouse location, size, and crop to be grown will help determine Bielinski Santos* the design requirements. University of Florida Wimauma FL; bmsantos@ufl.edu Specified Source(s) of Funding: Federal competitive Bureau of Rec- Craig Chandler lamation University of Florida Wimauma FL; ckc@ufl.edu Steven Sargent University of Florida, Gainesville; sasa@ufl.edu 4:45–5:00 pm Leveraging Waste Sites for Year-Round, Affordable Protected strawberry production is widely used in Europe and other parts of the world; however, in California and Florida open-field pro- Specialty Crop Production in Temperate Climates duction remains as the main production system. Strawberry production Cary Mitchell* in high tunnels could potentially increase yield, improve fruit quality, Purdue University West Lafayette IN; [email protected] promote early ripening, reduce pest incidence as well as rain damage. Gioia Massa If adopted in Florida, this technology opens new doors for long-term changes on strawberry production practices and an eventual increase Purdue University West Lafayette IN; [email protected] in grower profits. The objectives of this study were: a) to compare A capital project is underway at Purdue University to bottom-heat the growth, fruit earliness and yield of strawberry cultivars; and b) to high tunnels with water recirculated between the campus power plant examine the difference in postharvest quality of strawberries grown and an adjacent crop-production site. Hot water from boilers typically under tunnels and open fields. The cultivars Strawberry Festival, Winter transfers heat to the atmosphere in cooling towers. Piping that hot water Dawn, Ruby Gem, and 00-51 were tested inside of 16-ft. high tunnels instead below ground can warm roots and air in closed tunnels during and in open fields during the 2006-07 and 2007-08 seasons. Resulting cold weather. Specialty crops will be tested for significant extension data showed that the yields of Strawberry Festival, Winter Dawn, Ruby of growing seasons well before and after what typically occurs in non- Gem and 00-51 increased by 36%, 70%, 66%, and 87% in the tunnels heated tunnels at northern latitudes. Engineering analyses indicate that in comparison with the open fields in the 2007-08 season, when early soil and air will be warmed within closed tunnels during cold weather freezes occurred. Postharvest quality followed the same trends. sufficient to avoid chilling temperatures. Various vegetable, small Specified Source(s) of Funding: Private (Association, Foundation, In- fruit, and ornamental species will be tested for multiple or continuous dustry) Industry/Association Program Name, Award Number: Florida in-ground cropping potential in a temperate climate where extended Strawberry Growers Association and North America Strawberry field production is not possible or where protected winter cultivation Growers Association has not been economically viable. Waste-energy-leveraged protected production will negate the need for long-distance transport of specialty- crop harvest during cold seasons and create local jobs and revenue. 4:30–4:45 pm Environmental instrumentation of the tunnels in this study will monitor soil and air temperatures, water use, and daily light integral through- Evaporative Cooling—Water Use for Greenhouse out the year. Carbon dioxide will be adjusted as needed from waste Environmental Control sources during periods of extended tunnel closure. Crop performance Gene Giacomelli* throughout the year will be correlated with seasonal profiles of envi- The University of Arizona, Tucson; [email protected] ronmental variables. A GIS study is underway to identify sites in 22 counties of northwest Indiana where thermal and/or organic wastes Nadia Sabeh are produced or accumulate and where nearby unused land might be GLHN Architects and Engineers Tucson AZ; [email protected] used for waste-energy-leveraged crop production. Anticipated R&D Chieri Kubota issues include determining needs for photoperiod modification, finding The University of Arizona, Tucson; [email protected] suitable off-season pollinators, and pest and disease control without freeze-thaw conditions. Anticipated advantages include significantly Evaporative cooling systems are used for cooling and humidifying higher annual productivity and yield rates related to protected condi- greenhouses. The system design, the operational procedures, and the tions minimizing environmental stress, as well as enhanced water-use system maintenance all contribute to the performance of the evaporative efficiency due to wind protection, humidification, and recycling of cooling system in terms of the amount of cooling and the water use. The condensate and rainwater. process requires that inside air is removed and replaced with fresh air from the outside the greenhouse. Two methods of ventilation, mechani- Specified Source(s) of Funding: Department, College, State and/or cal and natural, are commonly used. Mechanical ventilation requires HATCH 2007 New Manufacturing Economy Booster Grant the use of fans to actively exchange air and has the primary advantage of being able to control ventilation rates. Natural ventilation uses vent openings (in the roof or sidewalls) to passively exchange air and has 5:00–5:15 pm the primary advantage of requiring no electrical power and thus low Biogas Slurry Dilution: Good Nutrient Solution in operational costs. The process of cooling and humidifying the air by Decreasing Nitrate Concentrations of Lettuce in evaporating liquid water is called evaporative cooling. A large quantity of heat must be transferred from the surroundings to the water to cause Hydroponics the water to evaporate. In a greenhouse, heat is transferred from the air Wenke Liu to the liquid water, causing the temperature of the air to decrease and Chinese Academy of Agricultural Sciences Beijing, China; the vapor content of the air to increase when water is evaporated. Fan [email protected] and pad evaporative cooling has fans at one end of the greenhouse that Lianfeng Du* pull outside air into the greenhouse through a wetted pad, reducing the temperature and raising the humidity of the entering air. Fog evaporative Beijing Academy of Agro-forestry Sciences Beijing, China; cooling injects droplets of water into the greenhouse air through a series [email protected] of nozzles. High-pressure-fog systems inject very fine water droplets HORTSCIENCE, VOL. 43(4), JULY 2008 1085 Qichang Yang Eric Simonne Chinese Academy of Agriculture Sciences Beijing, China; University of Florida, Gainesville; esimonne@ufl.edu [email protected] James White Human health is being threatened by excess nitrate intake through University of Florida, Apopka; jmwhi39@ufl.edu dietary pathway (vegetables and drinking water) worldwide, and Danielle Treadwell vegetables are the primary source (about 80%) for large quantitative ingestion and their biological characteristics of nitrate accumulation, University of Florida, Gainesville; ddtreadw@ufl.edu r especially for leafy vegetables, e.g. lettuce. In this paper, mechanisms Amarat Simonne and research advances of biogas slurry dilutions in decreasing ni- University of Florida, Gainesville; asim@ufl.edu trate concentration of lettuce in hydroponics were summarized. It is concluded that biogas slurry dilutions were efficient in lowering the Elizabeth Lamb nitrate concentrations in lettuces. Therefore, it is assumed that biogas Cornell University Ithaca NY; [email protected] slurry dilutions can be developed commercially to be nutrient solutions Sustainable agriculture combines plant and animal production, for low-nitrate vegetables production in hydroponics in horticulture integrates natural biological cycles, and makes the most use of non- practice based on abundant resources of biogas slurry in China. renewable resources. Aquaponics links hydroponics with aquaculture and requires reconciling water quality for three groups of organisms— plants, fish (or other aquaculture products), and nitrifying bacteria. 5:15–5:30 pm Plants and fish are cash crops while bacteria oxidize fish by-product Vegetable Production in Nutrient Film Technique ammonia into nitrate. System water pH affects these organisms and System Affected by the Treatment of Water with Natural may be managed to optimize system sustainability. Batch trials based on startup characteristics for bringing new biological filters up to full Minerals capacity found that total ammonia nitrogen (TAN) concentration in Md. Abul Kalam Azad* system water decreased from 5 to 0 mg·L-1 in 28, 20, and 12 days after Kochi University Nankoku-shi 783-8502, Japan [email protected] introduction of nitrifying bacteria to perlite biofilters when recirculating water pH was 6.5, 7.5 and 8.5, respectively. TAN removal from Noriko Takeda mature biofilters operating under aquaponic conditions occurred at Kochi University Nankoku-shi, Japan; [email protected] the rate of 19, 31 and 80 g·m3 per day with recirculating water pH Katsumi Ishikawa at 6.0, 7.0, and 8.0, respectively. A linear decrease in early market- Kochi University Nankoku-shi, Japan; [email protected] able cucumber fruit yield occurred as water pH increased from 5.0 to 8.0, however, there was no difference in total yield. More research Sheheli Islam on other plant/fish/system combinations is needed. However, for Kochi University Nankoku-shi, Japan; [email protected] the cucumber/tilapia/recirculating tank culture system under study Naima Islam here, maintaining system water pH near 8.0 will increase ammonia Kochi University Nankoku-shi, Japan; [email protected] biofiltration by nitrification, thereby allowing higher fish stocking densities, producing more plant nutrients from fish waste. This will Treatment of water using natural minerals such as quartz porphyry conserve applied fertilizer and thereby improve aquaponic systems (QP), which contains many substances that easily ionize with water sustainability. was developed for the improvement of water quality. The cultivation of komatsuna vegetables (Brassica rapa L. nothovar) was carried out Specified Source(s) of Funding: Department, College, State and/or hydroponically in a nutrient film technique (NFT) system applying the HATCH water treatment method. Results showed that komatsuna plants grew vigorously in summer (July–Aug.), reasons cited as high and long duration of solar radiation, and air temperature. Alternatively, plants grew 5:45–6:00 pm less vigorously in winter (Dec.–Feb.), because of lower and shorter Benefits of High Tunnels for Southern Highbush duration of solar radiation, and air temperature. Although different Blueberry Production Include Frost Protection and growth parameters such as leaf length, leaf width, and fresh weight of plants increased a little, the coefficient of variation became smaller by Early, Large Yields using QP treated water/nutrient solution. However, an improvement in Andrew Ogden* plant growth occurred in receiving QP treated water/nutrient solution. University of Georgia Athens GA; [email protected] The effects of QP treatment appeared in the freshness of komatsuna Gerard Krewer plants after harvest. The reduction percentage of moisture in plants was alleviated by using the treatment system. Results also showed University of Georgia Tifton GA; [email protected] that the acceleration of ion exchange due to the treatment enabled to Elvin Andrews maintain the balance of ions in the nutrient solution, and thus plants University of Georgia Lakeland GA; [email protected] grew homogeneously. Furthermore, results suggested that the water treatment system with QP could be applicable for the vigorous produc- Marc van Iersel tion of high quality vegetables. University of Georgia Athens GA; [email protected] Specified Source(s) of Funding: Department, College, State and/or High tunnels are gaining popularity for fruit and vegetable produc- HATCH JSPS Postdoctoral program, Japan Award Number: P tion. Earliness of yield, higher yields, and an increase in the fraction 06442 of marketable fruit have been achieved with many horticultural crops in high tunnels. These findings spurred us to examine the production of organic southern highbush blueberries in high tunnels at two loca- 2 5:30–5:45 pm tions in Georgia. Six high tunnels, each 53.5 m , and two outdoor plots were constructed in Athens (Northeast Georgia). Blueberry cultivars Sustainability of Recirculating Aquaponic Systems Is ‘Emerald’ and ‘Jewel’ were planted in raised pine bark beds. Frost Influenced by System Water pH protection was provided with propane heaters. Data taken included Richard Tyson* soil and air temperature, inflorescence development rates, and yield. University of Florida Sanford FL; rvt@ufl.edu Similar data were collected in Homerville (South Georgia), where a 0.19-ha Haygrove three-bay high tunnel was erected over an existing

1086 HORTSCIENCE, VOL. 43(4), JULY 2008 planting of ‘Star’ and ‘Millenium.” The ideal date of tunnel closure for 2.8%) due to delayed attainment of orange color. Respiration rates for maximum and early yield was tested in Athens with three closure dates controls were 13.5, 14.3 and 34.8 mL CO2/kg/h at 5 °C, 10 °C, and (Dec. 15, Jan. 2, and Jan. 20). Higher soil and air temperatures inside 20 °C, respectively; treated fruit had similar respiration rates. The ORALS–MONDAY the tunnels catalyzed flowering, fruit-set, and initiation of vegetative treated fruit had better appearance as indicated by lower incidences growth at dates earlier than in outdoor beds. The latest closure date of fin browning, stem-end shriveling, and surface scald. However, at produced the higher yield (150 g/plant for ‘Emerald’) than the earlier orange stage fin margins remained green. closure dates (75 and 60 g/plant respectively). The Dec. 15 closure produced the earliest yield (peak harvest: Apr. 30) compared to both Specified Source(s) of Funding: Federal competitive Southern Region later closure dates (May 15). In Athens, the Easter freeze of 2007 (-4.5 SARE degrees °C) destroyed all outdoor fruit. Although the freeze was not as severe (-3.3 degrees °C) in Homerville, both cultivars yielded much more inside the high tunnels than outdoors (‘Millenium’ 468 g/plant 4:30–4:45 pm outdoors vs. 1,404 g/plant indoors). Freeze protection was provided Effects of Delayed Controlled Atmosphere Storage of by a single large shop heater. In Homerville, harvest was advanced Apples After Rapid 1-MCP Treatment by about one week. Freeze protection without water use, combined with high, early yields and rain protection at harvest are advantages Christopher B. Watkins* offered by high tunnels. Cornell University Ithaca NY; [email protected] Specified Source(s) of Funding: Federal competitive USDA integrated Jacqueline F. Nock organic grant Cornell University Ithaca NY; [email protected] Recommendations for maximum acceptable delays after harvest for treatment of apple fruit with 1-methylcyclopropene (1-MCP) vary by cultivar and growing region. However, not all storage operations Oral Session 6: can fill storage rooms within a short period of time. Therefore, we Postharvest Physiology - 1-MCP and Ethylene have investigated the effects of delayed controlled atmosphere (CA) storage after treatment of fruit with 1-MCP within 2 days of harvest. Monday, 21 July 4:15–6:00 pm Salon 10 ‘McIntosh’ and ‘Empire’ apples were harvested from different regions -1 Moderator: Jennifer DeEll, [email protected] in New York and treated with 1 L·L 1-MCP after cooling overnight to 2 °C. Fruit were stored in CA (‘McIntosh’, 2% O2/2% CO2 and 2% O2/5% CO2 after 5 weeks; and ‘Empire’, 2% O2/2% CO2) after 2, 7 4:15–4:30 pm or 14 days. Internal ethylene concentrations (IEC) remained low and Application of Aqueous 1-Methylcyclopropene to ‘Arkin’ firmness was maintained in 1-MCP treated fruit even if CA storage was Carambola Maintains Fruit Firmness delayed for 14 days. Variations in responses after 1-MCP treatment were related to maturity of fruit at harvest as indicated by IEC. In a Oren Warren* follow up experiment, Empire fruit were treated with 1 L·L-1 1-MCP University of Florida, Gainesville; owarren@ufl.edu after cooling overnight to 2 °C, 8 °C, or 12 °C. Fruit were kept at these Steven Sargent temperatures for 0, 7, or 14 days before being transferred to 2 °C and University of Florida, Gainesville; sasa@ufl.edu CA storage applied. After 10 months of CA storage plus 7 days at 20 °C, fruit treated with 1-MCP had no decay, but higher incidences of Donald Huber flesh browning and external carbon dioxide injury, irrespective of University of Florida, Gainesville; [email protected]fl.edu pre-storage temperature. However, the incidence of external carbon dioxide injury increased with increasing delay at warmer temperatures, Jeffrey K. Brecht and was higher at 12 °C than at 8 °C. Overall, the results show that University of Florida, Gainesville; jkbrecht@ufl.edu storage of fruit in CA can be delayed after treatment of fruit close to Adrian Berry harvest, but that slower cooling of fruit may increase risk of external University of Florida, Gainesville; [email protected]fl.edu carbon dioxide injury. Carambola (Averrhoa carambola L.) fruit are susceptible to mechani- Specified Source(s) of Funding: Department, College, State and/or cal damage after harvest because of their unique shape; therefore, HATCH HATCH GUA0206 carambola are typically harvested commercially at color break stage (<1/4 yellow) and ripened during storage and handling. 1-methylcyclopropene (1-MCP) maintains appearance and firmness of climacteric 4:45–5:00 pm and nonclimacteric fruit by inhibiting ethylene action. Carambola fruit Differential Sorption of 1-MCP to Fruit Tissues, (‘Arkin’) were harvested at three stages of maturity (color break, 1/2 yellow, and 3/4 yellow). The following day the fruit were immersed Structural Polysaccharides, and Lignin for 1 min in aqueous 1-MCP (200 ug/L), dried and stored at 5 °C, Sun Tay Choi 10 °C or 20 °C. After 14 d storage, half of the fruit were analyzed. University of Florida, Gainesville; [email protected] The remaining fruit were transferred to 20 °C and analyzed upon Donald Huber* reaching the orange stage, the limit of acceptability. Untreated color break, 1/2 yellow, and 3/4 yellow fruit reached orange stage in 12, University of Florida, Gainesville; djhuber@ufl.edu 7 and 7 d, respectively. 1-MCP delayed time to orange stage from 2 Published reports have noted differential binding of 1-MCP to different to 5 d at all storage temperatures for fruit harvested at color break plant materials, possibly due to oils and insoluble components, such and 1/2 yellow color stages regimes. 1-MCP treatment did not delay as cellulose. In the present study, we demonstrate differential sorp- time to orange stage for fruit harvested at 3/4 yellow color stage. tion rates and capacities among different fruits, tissues within fruits, Fruit treated with 1-MCP were firmer than the controls, irrespective and cellular components including oils, polysaccharides, and lignin. of harvest color stage or storage temperature. Upon reaching orange Plant materials (20 g) were sealed in 130-mL jars and provided with stage, 1-MCP-treated and untreated fruit stored at 5 °C had respective gaseous 10 µL·L-1 (3.1 µg) 1-MCP (SmartFresh Quality System). In bioyield points of: color break = 16.4 N and 9.7 N; 1/2 yellow = 9.6 N all fruits examined, sorption rates and capacities were significantly and 5.6 N; 3/4 yellow = 12.3 N and 5.9 N. 1-MCP had no significant higher for epidermal/exocarp tissues compared with mesocarp tis- effect on weight loss during 14 d of storage. Color break fruit treated sues. Sorption was particularly high in the exocarp of avocado and with 1-MCP lost more weight (2.7% to 4.2%) than controls (1.8% to

HORTSCIENCE, VOL. 43(4), JULY 2008 1087 plantain, which depleted system 1-MCP levels within 30 min. Dried to gaseous 1-MCP had delayed ripening (12 and 16 d, respectively) fruit tissues showed a 50% to 70% reduction in sorption capacity that with fairly uniform mesocarp softening. Shriveled appearance and was recovered upon rehydration. For many tissues, sorption capacity decay were the limiting quality factors. was significantly greater (mass basis) than that of pure avocado or safflower oil. Avocado mesocarp treated to remove oil showed reduced Specified Source(s) of Funding: Department, College, State and/or sorption whereas exocarp was minimally affected, indicating that HATCH different cellular components contribute to sorption in different plant materials. Sorption to polysaccharides ranged from 30% (xyloglucan), to 40% to 45% (cellulose, polygalacturonic acid), and 90% for highly 5:15–5:30 pm esterified pectin. By far the highest sorption rate and capacity was Preharvest Use of 1-MCP (Harvista™ Technology) in exhibited by commercial (sugarcane) and plantain-exocarp lignin. Orchards: Effect on Storage Quality of Packham’s Initial-rate sorption kinetics for plantain lignin and avocado oil were comparable but binding capacity significantly greater in lignin. The Triumph Pears data demonstrate that 1-MCP sorbs to several cellular targets and that Claudia Moggia* hydrophobic components are preferred sorption sinks. During 24-h Universidad De Talca Talca, Chile; [email protected] exposure to 10 µL·L-1 gaseous 1-MCP or ethylene (non-sorbing), Jose Antonio Yuri quantities diffusing through disks of avocado exocarp (4.3% 1-MCP, 34.3% ethylene), and tomato epidermis (6.9%, 8.5%) and pedicel-scar Universidad De Talca Talca, Chile; [email protected] (5.2%, 33.2%) tissues were consistent with tissue 1-MCP sorption, Marcia Pereira and support the conclusion that quantities of 1-MCP accumulating Universidad De Talca Talca, Chile; [email protected] in internal tissues of some commodities may be considerably lower than previously thought. Daniel Manriquez Agrofresh Chile Santiago, Chile; [email protected] Specified Source(s) of Funding: Department, College, State and/or HATCH Private (Association, Foundation, Industry) The effect of 1-MCP sprayable formulation, Harvista™ Technology, was evaluated in two commercial orchards of Packham’s Triumph pears, during the 2006-07 season. The orchards were located in the 5:00–5:15 pm central valley of Chile (Molina, 35 07 South Lat; 71 17 West Long.; and San Clemente 35 30 South Lat.; 71 28 West Long). Harvista™ Postharvest Applications of Aqueous and Gaseous Technology was applied at 0 and 100 mg·L-1 a.i., 7 days before com- 1-Methylcyclopropene Delay Ripening in ‘Monroe’ mercial harvest using a backpack sprayer. Fruit were harvested at a Avocado commercial date (day 0) and 7 days after the first pick. Additionally, at storage, half of the fruit of each preharvest treatment, was applied Marcio Pereira* with 1-MCP post-harvest formulation, SmartFresh™ at a rate of 200 University of Florida, Gainesville; mecp@ufl.edu ppb. This treatment was done on cold fruit. Pears were treated with Steven Sargent* 1-MCP for 24 hours in sealed chambers prior to transferring to cold University of Florida, Gainesville; sasa@ufl.edu storage. Fruit was stored at -1 °C, 90% to 95% RH for 60, 90, and 120 days. Skin color (with colorimeter), firmness, and ethylene production Jonathan Crane rate were measured at each removal plus 1, 7, and 14 days at room University of Florida, IFAS, TREC Homestead FL; jhcr@ufl.edu temperature (20 °C). Application of Harvista™ Technology did not Donald Huber affect maturity indexes at harvest; however, it had an effect during stor- University of Florida, Gainesville; djhuber@ufl.edu age. The main differences were seen in higher flesh firmness, greener color retention and lower ethylene production rate; moreover, values ‘Monroe’ avocados (Persea americana Mill.) were harvested at mature- were similar to those of fruits treated with SmartFresh™. The effect green stage and treated with an aqueous formulation of 1-MCP [(225, of Harvista™ Technology was more prominent with shorter periods 450 or 900 g L a.i. for 1 or 2 min at 20 °C or gaseous 1-MCP (900 of storage and in earlier harvested fruit (day 0). As it happens with nL/L for 12 h at 20 °C) (completely randomized design; n=4 fruit)]. SmartFresh™, the effects of Harvista™ Technology were extended After treatment, fruit ripening was monitored at 20 °C. Respiration during simulation of shelf-life (specially after 7 days at 20 °C). A delay and ethylene production rates were measured daily, whileweight loss, of 7 days in harvest allowed an important increase in fruit size, with epidermal color and whole fruit firmness were determined every other an average enlargement in weight of 15%. day. Fruit were considered commercially ripe upon reaching 10-20 N firmness at the equator (5-cm dia. flat-plate probe at 2.5 mm deforma- Specified Source(s) of Funding: Private (Association, Foundation, tion). Control fruit softened to 10-20 N in 14 d. All aqueous 1-MCP Industry) treatments delayed ripening 12-16 d beyond the controls, with 2-min immersion and gaseous 1-MCP treatments showing the greatest effect. External color change for treated fruit was similar to controls, but at a 5:30–5:45 pm slower rate. Peak respiration and ethylene production rates of control Preharvest Application Timing of Sprayable 1- fruit was 124 mg Kg-1·h-1 of CO and 299 L Kg-1·h-1 of C H , respectively, 2 2 4 Methylcyclopropene Influences Postharvest Behavior of whereas rates for the various 1-MCP treatments were reduced by 16% to 40% (respiration) and 26% to 44% (ethylene). Fruit immersed in Pears and Apples aqueous 1-MCP at 900 g/L for 1 min or in 450 or 900 g/L for 2 min Jennifer DeEll* maintained firmness values >30 N for 28 d but exhibited severe decay. Ontario Ministry of Agriculture, Food and Rural Affairs Simcoe, ON Fruit treated with aqueous 1-MCP softened non-uniformly (stem end Canada; [email protected] firmer than blossom end), and ripening asynchrony was enhanced Behrouz Ehsani-Moghaddam with increased immersion time and 1-MCP concentration. Avocados treated with gaseous 1-MCP ripened somewhat slower than the 900 Ontario Ministry of Agriculture, Food and Rural Affairs, Simcoe, ON µg·L-1 aqueous 1-MCP treatment, but fruit from the former treatment Canada; [email protected] softened more uniformly and were fully ripe in 30 d. Treated fruit Todd Edgington lost 15% to 18% weight and were significantly shriveled when soft AgroFresh Inc., Spring House PA; [email protected] due to extended ripening time, whereas control fruit lost 8% weight. Fruit immersed in 225 µg·L-1 aqueous 1-MCP for 1 min or exposed A sprayable formulation of 1-methylcyclopropene (1-MCP) was applied

1088 HORTSCIENCE, VOL. 43(4), JULY 2008 to mature ‘Bartlett’ pear and ‘McIntosh’ apple trees 7 and 3 days prior and storage. After storage, 1-MCP reduced the number of abscised to anticipated optimum harvest. Spray treatments included 60 or 120 leaves and increased subsequent rooting for ethephon-treated cuttings g of 1-MCP (Harvista™) per acre with 1% oil and 0.05% surfactant. of both species. However, root number with ethephon and 1-MCP Unsprayed control pears were treated postharvest with or without was less than the control (without ethephon or 1-MCP). Finally, the gaseous 1-MCP (SmartFresh™, 0.3 L·L-1 for 24 h at 3 °C), while all effectiveness of 1-MCP was evaluated during commercial shipping sprayed and non-sprayed apples were also treated postharvest with or of ethephon-treated liners, where 1-MCP significantly decreased without gaseous 1-MCP (1.0 L·L-1 for 24 h at 3 °C). Fruit were stored leaf abscission. Release rate of 1-MCP from sachets was measured at 0.5 °C for 4 months and then assessed for quality during 1-week over time. 1-MCP level increased from 0.25 mg·L-1 at 2 mins to 1.4 at 20 °C. There was little effect of 1-MCP spray on fruit maturity at mg·L-1 at 1 h, with a maximum 2.5 mg·L-1 at 24 h. Overall, 1-MCP optimum harvest. However, if sprayed fruit remained on the trees for sachets effectively reduced ethylene-related problems in Lantana and 11 days longer, pears exhibited delayed color change (green to yel- Euphorbia cuttings and liners during storage. low), softening, and starch degradation, while apples were firmer and had lower internal ethylene concentration, compared to non-sprayed Specified Source(s) of Funding: Department, College, State and/or controls. 1-MCP spray delayed ethylene production, firmness loss, and HATCH Private (Association, Foundation, Industry) University of yellowing in pears during cold storage, and these effects were more Florida IFAS undergraduate research Industry/Association Program notable in fruit sprayed 3 days (vs. 7 days) prior to harvest. ‘Bartlett’ Name, Award Number: Young Plant Research Center Hill Founda- pears treated postharvest with gaseous 1-MCP exhibited greater firmness tion ORALS–TUESDAY retention than those sprayed preharvest with 1-MCP. Pears developed senescent scald after 7 days at 20 °C and there was lower incidence in fruit sprayed 3 days compared to 7 days before harvest. Postharvest Oral Session 7: Propagation/Asexual Propagation gaseous 1-MCP treatment also reduced the incidence of senescent scald and eliminated internal browning in pears, whereas controls Tuesday, 22 July 8:00–9:30 am Salon 10 and those sprayed preharvest with 1-MCP had similar incidence of internal browning. ‘McIntosh’ apples sprayed preharvest with 1-MCP Moderator: Kim Bowman, [email protected] were firmer and had lower internal ethylene concentration after cold storage. However, these effects were less evident in apples sprayed 8:00–8:15 am 7 days (vs. 3 days) prior to harvest and the effects were lost after 7 days at 20 °C. Apples treated postharvest with gaseous 1-MCP, with or Photosynthetic Daily Light Integral during Propagation without preharvest 1-MCP spray, exhibited the lowest internal ethylene Influences Rooting and Growth of Cuttings and and greatest firmness and acidity retention after storage. Subsequent Development of New Guinea Impatiens and Specified Source(s) of Funding: Department, College, State and/or Petunia HATCH Oklahoma State University Division of Agricultural Sciences Roberto Lopez* and Natural Resources Team Initiative Program. Purdue University West Lafayette IN; [email protected] Erik Runkle Michigan State University, East Lansing; [email protected] 5:45–6:00 pm Effects of 1-MCP Sachets on Postharvest Quality of A majority of commercial propagation of herbaceous ornamental cuttings occurs during the winter when the photosynthetic daily light Lantana and Euphorbia Cuttings and Liners integral (DLI) is relatively low. We quantified how the mean DLI influ- Ana Maria Borda* enced rooting and subsequent growth and development of two popular University of Florida, Gainesville; amborda@ufl.edu vegetatively propagated species, New Guinea impatiens (Impatiens hawkeri Bull.) and petunia ( Petunia hybrida hort. Vilm.-Andr.). Three Paul R. Fisher cultivars of each species were propagated under a mean DLI ranging University of Florida, Gainesville; pfisher@ufl.edu from 1.2 to 10.7 mol·m-2·d-1. Cuttings were rooted in a controlled Haley K. Parks greenhouse environment maintained at 24 to 25 °C, with overhead University of Florida, Gainesville; yelah63@ufl.edu mist, a vapor-pressure deficit of 0.3 kPa, and a 12-h photoperiod. In a separate experiment, rooted cuttings under DLI treatments were then Terril Nell transplanted into 10-cm containers and grown in a common greenhouse University of Florida, Gainesville; [email protected]fl.edu at 20 2 °C under a 16-h photoperiod to identify any residual effects on Previous research has shown that 1-MCP (1-methylcyclopropene) can subsequent growth and development. In both species, rooting, biomass desensitize Lantana cuttings to ethylene, and reduce leaf abscission accumulation, and quality of cuttings increased and subsequent time and epinasty symptoms. The objective was to evaluate whether 1- to flower generally decreased as mean propagation DLI increased. MCP sachets(EthylBloc™ Sachets) are an effective delivery method For example, root number of petunia ‘Tiny Tunia Violet Ice’ after to treat Lantana camara ‘Samantha’ and Euphorbia ‘Diamond Frost’ 16 days of propagation increased from 17 to 40 as the propagation unrooted cuttings and rooted liners. Ethylene was applied as a gas at DLI increased from 1.2 to 7.5 mol·m-2·d-1. In addition, cutting shoot the same time as 1-MCP application, or via an Ethephon (Florel™) height decreased from 6.3 to 4.5 cm, and root and shoot dry biomass spray prior to 1-MCP. Unrooted cuttings were placed into low-density of cuttings harvested after 16 days of propagation increased by 737% polyethylene plastic bags that were either closed, open, or closed and 106%, respectively. Subsequent time to flower from the beginning of propagation decreased from 50 to 29 days as propagation DLI and perforated on both sides. The bags were placed into sealed glass -2 -1 tanks and ethylene gas was applied at 0.9 mg·L-1. Three replicate increased from 1.4 to 10.7 mol·m ·d regardless of the DLI provided tanks contained 1-MCP sachets and three tanks did not contain 1- after propagation. In New Guinea impatiens ‘Harmony White’, root MCP. Tanks were sealed for 48 hours and maintained at 21 °C in the and shoot dry weight of cuttings increased by 1038% and 82%, respectively, and subsequent time to flower decreased from 85 to 70 dark (the storage treatment used in all experiments). 1-MCP greatly -2 -1 reduced the number of abscised leaves in cuttings of both species days as the propagation DLI increased from 1.2 to 10.7 mol·m ·d . regardless of the type of bag used, indicating that both ethylene and These experiments quantify the role of the photosynthetic DLI during 1-MCP penetrated the bags. Root number was higher for cuttings propagation on the rooting and subsequent growth and development stored with ethylene and 1-MCP compared with cuttings stored with of vegetatively propagated herbaceous cuttings. ethylene and no 1-MCP. In a separate trial, stock plants were sprayed Specified Source(s) of Funding: Department, College, State and/or -1 with either water or 500 mg·L ethephon 1 day before cutting harvest HATCH Federal competitive USDA-ARS Specific Coop. Agree-

HORTSCIENCE, VOL. 43(4), JULY 2008 1089 ment 58-6402-4-026 with CRIS MIS-223010. Specific project: Field roughly doubles every 3 weeks and the propagation rate is 2× where Establishment of Medicinal Herbs and Potential for Commercial × is the number of cycles that the plants are cut back. We reduced the Production” plant density from 1440 plants per bed (3 m × 1.2 m) to 180, 120, 90, and 60 plants per bed. Shoots were tipped when they had 8, 12, 16, and 24 nodes and bended over the media for rooting and lateral 8:15–8:30 am buds to sprout. Time for the vines to cover the beds increased from three to five weeks as planting density decreased. Lateral shoots were Carbon Dioxide Fertilization of Ex-vitro Anthurium obtained in all treatments increasing the propagation rate accordingly. andraeanum Plantlets Supplemental light to maintain 24 h continuous photosynthesis of the Richard A. Criley* mother plants was also evaluated and the number of shoots per plant University of Hawaii Honolulu HI; [email protected] in a 3-week period doubled. These strategies accelerate growth and reduce transplant shock increasing slip outcome from a reduced number Teresita Amore of expensive certified G0 germplasm from tissue culture. In addition, University of Hawaii Honolulu HI; [email protected] transplanting labor is reduced since there are fewer plants per bed. Joanne S. Lichty Specified Source(s) of Funding: Department, College, State and/or University of Hawaii at Manoa Hilo HI; [email protected] HATCH Machiko Kashiwagi University of Hawaii at Hilo Hilo HI; [email protected] 8:45–9:00 am

The use of carbon dioxide (CO2) to increase plant growth rates is a Nutrient Supply during Cutting Propagation technology nearly a half century old, and it is in use in closed green- Kathryn Santos* house systems for many cut flower and some vegetable crops. Carbon dioxide has also been used during in vitro culture to replace sugar in University of Florida, Gainesville; kmsantos@ufl.edu media. Establishment of plantlets removed from aseptic media has Paul Fisher been a challenge for some species. These experiments were conducted University of Florida, Gainesville; pfisher@ufl.edu to determine whether the addition of CO2 to enclosed community pot culture of anthurium plantlets ex vitro would improve growth rate, William Argo Blackmore Co. Belleville MI; [email protected] quality, and survival success. The CO2 was administered during the morning hours with no attempt to maintain a constant concentration. In The objective was to quantify the effect of macronutrient supply dur- the first experiment (15-second pulse at 15-minute intervals), plantlets ing different phases of growth during propagation of petunia cuttings. of UH1651 given CO had longer and wider leaves, 40% greater dry 2 The constant fertigation with a “Complete” water-soluble fertilizer weight and 25% greater dry weight, but leaf counts were equal after 3 containing (in mg/L) 75 NO3-N, 25 NH -N, 12 P, 83 K, 20 Ca, 10 months of exposure. Plantlet survival was greater in the CO -supplied 4 2 Mg 2 Fe, 1 Mn, 1 Zn, 0.5 Cu, 0.5 B, and 0.2 Mo over four weeks was pots. In a second experiment (32-second pulse at 30-minute intervals) compared to substituting a fertilizer containing only micronutrients conducted at the Greenpoint Nursery (Kurtistown, Hawaii), UH2007 during each of the first three weeks (week 0-1, week 1-2, or week plantlets (a pink butterfly obake hybrid) given CO over a 3-month 2 2-3) of propagating Supertunia ‘Royal Velvet’. Under constant fer- period had stem diameters thicker by 60% than the controls, longer tigation with the Complete fertilizer, plant dry weight doubled from and wider leaves, and fresh weight 40% greater and dry weight 56% day 0 (sticking of unrooted cuttings) to day 7 (0.02 g to 0.05 g), root greater than the control plantlets. Leaf number was only slightly greater, emergence was observed by day 4, and by day 7 the average length reflecting the slow growth rates of anthuriums in general. The CO 2 of primary roots was 2.6 cm. During the first week of propagation us- plantlets, however were chlorotic, reflecting the unsatisfied nutrient ing the Complete fertilizer, tissue-N concentrations dropped from an requirements of faster-growing plantlets. Survival was 100% in all average of 6.6% on day 0 to a minimum of 3.9% on day 11, followed CO -treated pots and all but one control pot. The results suggest that 2 by an increase to 4.7% from day 14 to 28. Percent P and K levels the addition of CO to enclosed spaces can enhance plantlet quality 2 followed a similar trend to N, with decreasing nutrient levels over following transplant from aseptic conditions as long as the mineral the first 11 days. During any week that the Complete fertilizer was nutrient supply is also increased in the medium. substituted with a fertilizer containing only micronutrients, tissue N, Specified Source(s) of Funding: Federal competitive Federal Program P, and K concentrations decreased compared with plants receiving the Name, Award Number: Federal Floriculture Grant (2003-34199-1401) Complete fertilizer. For example, plants receiving only micronutrients between week 0-1 had 20% lower tissue-N compared to those receiving the Complete fertilizer. Continual fertilization with Complete reduced 8:30–8:45 am root growth and increased the shoot:root ratio by week 2 and 3. The greatest root growth occurred when Complete was applied week 1 Reduced Plant Density and Vine Tipping Increase and micronutrients only were applied week 2, week 3, or weeks 2 Propagation Rate of Sweetpotato Slips in the Greenhouse and 3. The greatest shoot growth occurred by day 21 with constant Ramon Arancibia* fertigation. Although both shoot DW and leaf count increased once Mississippi State University-MAFES Pontotoc MS; [email protected] macronutrient fertilization was resumed during weeks 2 and 3, final shoot DW and leaf count were less than plants receiving Complete Scott Brown fertilizer from weeks 0 to 3. Further research is necessary to evaluate Mississippi State University-MAFES Pontotoc MS; [email protected] if observed responses transfer to other cultivars and species, and where unrooted cuttings differ in initial nutrition levels. Jeff Main Mississippi State University-MAFES Pontotoc MS; [email protected] Specified Source(s) of Funding: Private (Association, Foundation, Industry) -Department, College, State and/or HATCH Mark Shankle Mississippi State University-MAFES Pontotoc MS; [email protected] Certified G0 sweetpotato germplasm is propagated in greenhouses 9:00–9:15 am overwinter to increase slip supply for field production of G1 sweetpo- Citrus Greening Disease in Seedlings from Positive Trees tato seed stock. Traditionally, slips are densely planted (5 cm × 5 cm) Kim Bowman* in beds filled with soilless media. After 3 weeks, the new growth is USDA, ARS Ft. Pierce FL; [email protected] cut back and planted in new media. Therefore, the number of cuttings

1090 HORTSCIENCE, VOL. 43(4), JULY 2008 Ute Albrecht Oral Session 8: USDA, ARS Ft. Pierce FL; [email protected] Ornamentals/Landscape and Turf Citrus greening, or Huanglongbing (HLB), is a devastating bacterial disease of citrus that has recently been discovered in Florida and is Tuesday, 22 July, 8:00–9:45 am Salon 12 so widespread that it is considered impossible to eradicate. Primary components of HLB management/control include ensuring that trees Moderator: Rebecca Schnelle, rsflwr1@ufl.edu are disease-free at the time of planting into the field. Extensive efforts have been made to establish screen-protected sources of budwood for 8:00–8:15 am nursery propagations and develop protected screenhouse nurseries. At Ecological Restoration and Change in Biodiversity With present, most of the seed source trees for rootstock propagation are unprotected outdoors, and there are recent reports of some seed trans- and Without Horticultural Intervention mission of HLB. For this study, we have collected more than 10,000 Margaret Norton* seeds from trees of several different rootstock source trees known to be Scottish Agricultural College Edinburgh No United Kingdom margaret. HLB positive. HLB infection of individual fruit was characterized by [email protected] PCR testing of fruit peduncles. Seedlings from infected and uninfected Colin Norton* fruit were grown under carefully controlled greenhouse conditions ORALS–TUESDAY and tested at 3 months of age for HLB by PCR. Frequency of HLB Scottish Agricultural College Edinburgh No United Kingdom colin. infection (by PCR) and symptoms in seedlings were compared for [email protected] Presenter the different rootstocks. Implications for production of clean citrus Twenty species of local provenance native plants were grown from nursery stock worldwide will be discussed. seed collected in the north of Scotland and raised under nursery con- Specified Source(s) of Funding: Private (Association, Foundation, In- ditions. Plugs and larger plants were planted in clusters in severely dustry) Florida Citrus Production Research Advisory Council Grant disturbed land. Plant establishment was monitored over a 10-year period and comparisons were made between these areas and adjacent areas where no horticultural intervention had occurred. After 10 years, the number of individual plants of each species present varied, with 9:15–9:30 am fast colonising species e.g. Silene dioica, Stellaria holostea being Effect of Auxins and TDZ on In Vitro Regeneration of present both in areas with and without horticultural intervention. Pear cv. Nashpati The other species had spread to only a limited extent outside the Khalid M. Ahmad* planted area. Competition between species in the planted areas was monitored—five species showed a significant reduction in numbers Bahauddin Zakariya University Multan Multan, Pakistan compared with the start number. An increase in biodiversity over and [email protected] above the species planted was recorded in the areas with horticultural Aamir Nawaz intervention. However, the species balance was different from that of Bahauddin Zakariya University Multan, Pakistan [email protected]. nearby areas which had not been subject to the severe disturbance. pk Those areas had higher numbers of slow colonising species such as Mercurialis perennis and Blechnum spicant, suggesting that either Naveed Murtaza higher numbers of these species should have been planted in the Bahauddin Zakariya University Multan, Pakistan [email protected] horticultural intervention areas or a longer time is necessary for this Hypothesis that plant growth regulators effect the in vitro regeneration balance to be achieved. The nursery production methods developed response of Nashpati was tested in this investigation. Different concen- were satisfactory for all species. trations and combinations of NAA, IBA and TDZ was evaluated for in Specified Source(s) of Funding: Department, College, State and/or vitro regeneration of pear (Pyrus communis L.) cv. Nashpati. Murashige HATCH and Skoog (MS) medium was used as basal medium combined with different concentrations and combinations of TDZ, NAA and IBA. MCL (Cheveau and Leblay Regeneration Medium), CL vitamins, and 8:15–8:30 am SPSP (Cheveau and Skirvin Standard Pear Shoot proliferation Medium) Effect of Organic Mulches on Soil Properties, Physiology, with change in gelling component was used in these experiments. MS medium (6899: 4.4g in 1000 ml of dd water) containing IBA(uM) and and Growth of Landscape Shrubs NAA(uM) were tried for root initiation. Shoot segments (1 cm) were Bert Cregg* excised and cultured onto nutrition medium. Cultures were incubated Michigan State University, East Lansing; [email protected] in a growth cabinet at 23 °C to 25 °C under 2500 lux inflorescent light intensity with a 16-h photoperiod. Murashige and Skoog salts Robert Schutzki containing 2.0(uM) TDZ gave maximum shoot initiation percentage Michigan State University, East Lansing; [email protected] followed by MS + 0.5 (uM) NAA + 2.0(uM TDZ. Shoots initiated Landscape mulches are widely promoted to improve soil moisture were transferred to SPSP medium (Chvreau and Skirvin Standard retention, suppress weeds, and improve the growth of landscape plants. Shoot Proliferation Medium) and shoot proliferation and elongation The objective of this project was to determine the effect of common were quantified. Shoot obtained were transferred onto root induction landscape mulches on soil moisture, weed control, physiology, and medium. MS + 0.1 (uM) NAA + 5.0(uM) IBA gave maximum root growth of landscape shrubs. The study was installed in Summer 2004 initiation percentage followed by MS + 0.1 (uM) NAA. Rooted shoots at the Michigan State University Teaching and Research Center near were transferred onto MS (6b99: 1.7g) without PGRs for root elonga- East Lansing, MI. We planted 10 shrubs from 8 taxa (Euonymus tion. After two weeks in root elongation medium, the rooted plants alatus ‘Compactus’, Spiraea bumalda ‘Goldflame’, Weigela florida were transferred to plastic pots containing peat moss without nutrients ‘Java red’, Taxus media ‘Runyan’, Thuja occidentalis ‘Golden globe’, and placed in mist benches under plastic for acclimatization. All of Hydrangea paniculata ‘Tardiva’, Viburnum dentatum ‘Chicago lustre’, the plants were acclimatized and survived in field. and Viburnum trilobum ‘Compactum’) in 4 m × 4 m (12’ × 12’) plots. Specified Source(s) of Funding: Department, College, State and/or After planting, we mulched the plots to a depth of 8 cm (3”) with one HATCH Graduate studies Federal Program Name, Award Number: of four organic mulches: ground red pine bark, ground recycled pal- Higher education Commission of Pakistan lets, hardwood bark fines, or ground cypress mulch. All treatments were replicated four times. Two additional plots in each replication were not mulched; one plot served as an unmulched control, the other

HORTSCIENCE, VOL. 43(4), JULY 2008 1091 was maintained weed-free by hand-weeding and directed sprays of and 2100-2200 HR on clear calm days in mid-June and late August. glyphosate. All mulches were effective in controlling weeds through These measurements included air temperature at 5.0 m, 2.0 m, 1.0 m, the end of the 2005 growing season. Weed suppressing effect of mulch 0.5 m, and 0.25 m, as well as relative humidity at 2.0 m and surface began to break down during the 2006 growing season. All mulches temperature. Air temperatures were measured with shielded copper improved soil moisture relative to the unmulched treatments. Peaks constantan thermocouples, except at 2.0 m, where air temperature in soil moisture on unmulched plots corresponded to major rain and relative humidity were measured by a shielded HMP45C-L probe. events. Growth of shrubs was generally greatest on plots with pine Surface temperatures were measured with an Apogee IRR-PN infrared bark mulch. Mulches did not affect soil pH. Cypress mulch reduced thermometer. Surface temperatures in the native and xeric treatments photosynthetic rates, suggesting potential allelopathic effects on the were consistently warmer than in the oasis and mesic treatments. During shrubs. Maintaining plots weed-free resulted in growth similar to the afternoon and evening hours, the microclimates in the four treat- mulching for most shrubs. ments between 0.25 m to 2.0 m were different, with the mesic treatment cooler. At 5.0 m above the landscape surface, air temperatures within Specified Source(s) of Funding: Department, College, State and/or all four treatments were similar. HATCH Universidad de Colima Facultad de Ciencias Biologicas y Agropecuarias Fondo Ram n Alvarez-Buylla de Aldana Specified Source(s) of Funding: Federal competitive Federal Program Name, Award Number: National Science Foundation under Grant No. DEB-0423704, Central Arizona - Phoenix Long-Term Ecological 8:30–8:45 am Research (CAP LTER). Floral Induction of Two Woodland Sedges Esther McGinnis* 9:00–9:15 am University of Minnesota St. Paul MN; [email protected] Summertime Diurnal Gas Exchange Patterns of Arizona Mary Meyer Landscape Trees, Shrubs, and Herbs in Response to University of Minnesota St. Paul MN; [email protected] Landscape Design and Irrigation Carex radiata (Wahlenb.) Small and Carex pensylvanica Lam. are Chris A. Martin* two forest sedges with great horticultural potential. Both species are Arizona State University Mesa AZ; [email protected] in demand, because they are shade-tolerant groundcovers and are suitable for native restoration projects. However, low seed availability Kendra D. Busse limits their use. This experiment sought to promote commercial seed Arizona State University Mesa AZ; [email protected] production by studying the environmental cues necessary to induce Diurnal patterns of gas exchange were measured on 30 different species flowering. In the first experiment, mature plants were subjected to a of landscape trees, shrubs and herbs during Summer 2007 at the North 2 × 4 factorial that tested the interaction between vernalization and Desert Village (NDV) long-term experiment site. The NDV experiment photoperiod. Despite the fact that both species normally flower in site is an on-going long-term ecological experiment evaluating effects early spring, they exhibited different photoperiodic requirements. of landscape design and irrigation delivery on residential ecosystem Carex pensylvanica flowered best when exposed to 8-hour (short) function and social interactions. It consists of four treatment areas days while C. radiata flowered best in 16-hour (long) days. Neither variously designed and irrigated to represent the breath of landscape species exhibited an obligate vernalization requirement. In the second design and irrigation practices observed across the greater Phoenix experiment, germinated seed of C. pensylvanica were immediately metropolitan area. The four treatments areas are: 1) mesic [turf grass, exposed to a sequential photoperiod regimen to determine the fewest sprinkler irrigated (77.4 l/m2/month) exotic trees and shrubs]; 2) oasis days to flower. Using time-to-event data analysis, it was determined [turfgrass and decomposing granite, drip irrigated (16.4 l/m2/month) that C. pensylvanica flowers best when exposed to 16-hour (long) exotic trees, shrubs and herbs]; 3) xeric [decomposing granite, drip days for 6 weeks followed by 8-hour (short) days. irrigated (1.8 l/m2/month) exotic, shrubs and herbs]; and 4) native Specified Source(s) of Funding: Department, College, State and/or (decomposing granite, non-irrigated native trees, shrubs, and herbs). HATCH During Summer 2007, gas exchange measurements were made with an LI-6200 portable photosynthesis system under clear sky conditions during morning (700-900 HH), midday (1130-1330 HR), and late 8:45–9:00 am afternoon (600-1800 HR) hours. For all trees, shrubs and herbs, sum- Under Canopy Layer Temperature Profiles in an Arizona mer gas exchanges fluxes were generally highest during the morning except for herbs in the xeric and native treatments which had highest Residential Neighborhood in Response to Landscape gas exchange fluxes at midday. Summer gas exchange fluxes were Design and Irrigation generally lowest for trees in the mesic treatment. These data broadly Kendra D. Busse* suggest that during Arizona summer, the mid- and late-day inhibition Arizona State University Mesa AZ; [email protected] of leaf conductance of many landscape trees, shrubs, and herbs is in response to both regulation of internal leaf carbon dioxide levels and Chris A. Martin control of transpirational water loss. Arizona State University Mesa AZ; [email protected] Specified Source(s) of Funding: Federal competitive National Science North Desert Village is an area of student housing located on the Foundation under Grant No. DEB-0423704, Central Arizona-Phoenix ASU Polytechnic campus. Four treatments, each of which consist of Long-Term Ecological Research (CAP LTER) six houses, their associated yards and a common area in the middle, were planted in four archetypes of landscape design styles found in the Phoenix metropolitan area. These four design styles were mesic 9:15–9:30 am (sprinkler irrigated turf), oasis (mixture of drip irrigated trees and shrubs Historic and Horticulturally Significant Trees of Georgia and sprinkler irrigated turf), xeric (drip-irrigated trees and shrubs), and native (non-irrigated trees and shrubs). In order to understand the Sarah Swanner relationship between landscape design and microclimate created by University of Georgia Athens GA; [email protected] these landscapes, measurements were taken at 5.0-m increments along Timothy Smalley* five transects in each of four study sites between 900-1000, 1600-1700, University of Georgia Athens GA; [email protected] Presenter

1092 HORTSCIENCE, VOL. 43(4), JULY 2008 David Berle Oral Session 9: University of Georgia Athens GA; [email protected] Ornamental Plant Breeding 1 This project documented and geographically referenced the historic and horticulturally significant trees of Georgia. Nominations of sig- Tuesday, 22 July, 8:00–9:45 am Salon 11 nificant trees were obtained from garden clubs, Master Gardeners, city arborists and foresters, extension agents, and the general public. Moderator: Cynthia McKenney, [email protected] Significant trees were measured, evaluated for overall condition, photographed, and geographically referenced using GIS and GPS 8:00–8:15 am technology. The locations of 220 significant trees were examined relative to geographic regions, population centers, historic communities, Increased Seed Set and Inheritance of Seed Wings in and transportation systems. Population density explained 24% of the Interspecific Crosses between Coreopsis tinctoria and significant trees distribution. Significant trees within five miles of the Coreopsis leavenworthii 1874 Georgia railroad system accounted for 72.3% of all significant Sarah Smith* trees. Trees were categorized according to their significance, and the University of Florida Wimauma FL; smith04@ufl.edu Historic category included 55.9% of the significant trees. All significant trees were given a condition rating, and 85.0% of the significant trees Zhanao Deng ORALS–TUESDAY were within the excellent condition rating range. University of Florida Wimauma FL; zdeng@ufl.edu Specified Source(s) of Funding: Department, College, State and/or Coreopsis tinctoria and Coreopsis leavenworthii, two closely related HATCH species and both highly desirable for use in highway beautification and land reclamation, can cross-pollinate each other, resulting in formation of interspecific hybrids. It was reported that artificial in- 9:30–9:45 am terspecific hybrids from controlled crosses between the two species formed monovalents and trivalents during meiosis and their pollen Supraoptimal Mean Diurnal Temperature Delays Floral grains had low stainability. Conceivably it has been expected that Initiation in Poinsettia interspecific hybrids of these two species would have low seed set. In Rebecca Schnelle* this study, forty C. tinctoria individuals originating from Texas and University of Florida, Gainesville; rsflwr1@ufl.edu forty C. leavenworthii individuals from central Florida were cross- pollinated reciprocally as well as “self-pollinated” (i.e. intraspecifi- James Barrett cally) in the greenhouse. On each plant, 5 to 10 flower heads were University of Florida, Gainesville; jbarrett@ufl.edu individually pollinated and bagged. Seeds per pollinated flower head High temperature delay in floral initiation (heat delay) can cause were counted and examined for the presence of wings, a characteristic poinsettia and other short-day crops such as chrysanthemum to reach unique to C. leavenworthii. Surprisingly, interspecific crosses, either maturity later than desired producing considerable economic im- C. tinctoria × C. leavenworthii, or C. leavenworthii × C. tinctoria, pact. Previous studies have indicated that heat delay is the result of produced more seeds than C. tinctoria or C. leavenworthii self crosses high night temperatures around the time of floral initiation (Roberts did. This seems to indicate the existence of some level of heterosis in and Struckmeyer, 1938; Langhans and Miller, 1960; Miller and the interspecific crosses between these two closely related species. It Kiplinger, 1962). However, recent reanalysis of some of these data also indicates a need for evaluation of more filial generations to fully has revealed that heat delay in chrysanthemum is more strongly understand the effects of cross-pollination between the two species correlated to mean diurnal temperature than night temperature (Pearson on their progeny s fitness. Results also showed that seeds produced et al., 1993). A series of six experiments was conducted to determine from “selfing” C. tinctoria were wingless while seeds produced from if heat delay in poinsettia occurs in response to supraoptimal mean “selfing” C. leavenworthii were winged. When the two species were diurnal temperature. In growth chambers, floral initiation in Red cross-pollinated, the presence of wings on the seed was determined Velvet plants occurred 19.4 and 19.5 days after the onset of 12-hour by the maternal parents. Therefore, seed wings will have very limited dark periods with day/night temperature regimes of 21/27 ± 2 °C values in identifying potential interspecific hybrids between C. tinc- or 27/21 ± 2 °C respectively compared with 23.0 days with a con- toria × C. leavenworthii. stant 27 °C. Red Velvet plants exposed to a constant temperature of Specified Source(s) of Funding: Private (Association, Foundation, 24 2 °C underwent floral initiation in 17.7 days compared to 25.4 or Industry) Florida Wildflower Foundation 25.5 days with 29/24 ± 2 °C or 24/29 ± 2 °C day/night temperature regimes, respectively. In both experiments there were no significant differences in days to floral initiation between ‘Red Velvet’ and 8:15–8:30 am ‘Prestige Red’ plants within each temperature regime. Greenhouse experiments were conducted utilizing temperature treatments with The Effects of Cultivar, Ploidy Level, Direction of identical daytime high and overnight low temperatures but divergent Pollination, and Temperature on Seed Set and Production diurnal mean temperatures. Floral initiation in ‘Red Velvet’ occurred of Triploids in Lantana camara in 17.0 or 18.5 days with diurnal mean temperatures of 21 ± 2 °C David Czarnecki II* or 24 ± 2 °C compared to 25.0 days with a 27 ± 2 °C mean diurnal temperature. The average nighttime temperature in both of the University of Florida Wimauma FL; aggator@ufl.edu latter two treatments was 24 ± 2 °C. These data indicate that high Zhanao Deng temperature delay in floral initiation of poinsettia is the result of University of Florida Wimauma FL; zdeng@ufl.edu exposure to supraoptimal mean diurnal temperatures. Lantana camara (Verbenaceae) is a popular ornamental plant with a Specified Source(s) of Funding: Department, College, State and/or wide range of landscape uses. Numerous breeding programs are seek- HATCH ing to develop new Lantana varieties with desirable growth habits and flower colors, and improved landscape performance. In recent years, generation of triploids with high levels of male and female sterility has become another important objective in Lantana breeding. A major impediment to Lantana breeding has been extremely low seed set after

HORTSCIENCE, VOL. 43(4), JULY 2008 1093 cross-pollination. The effects of cultivar selection, ploidy level, direc- 8:45–9:00 am tion of pollination, and temperature on seed set and triploid production Applications of Microsatellites in Two Big Bracted were assessed in this study, with the objective to improve breeding techniques for higher breeding efficiency. Initially, controlled crosses Dogwood Species, Flowering and Kousa Dogwood were made among a dozen Lantana cultivars in two seasons to assess Xinwang Wang* parental compatibility and the ploidy of progeny produced. Based on The University of Tennessee Knoxville TN; [email protected] the data collected, three L. camara cultivars and one breeding line at Phillip Wadl two ploidy levels were then selected and paired into 12 crosses. For these crosses, controlled pollinations were made in the greenhouse Institute of Agriculture Knoxville TN; [email protected] over a period of six months. Results indicated that seed set varied Brian Scheffler significantly among crosses and was affected by parental cultivar and USDA-ARS MSA Genomics Laboratory Stoneville MS; brian. combination, ploidy level, and direction of crossing. Based on seed scheffl[email protected] production, parental cultivars could be categorized as male or female fertile. Results also showed a correlation between increased seed set Timothy Rinehart and an increased temperature in the greenhouse. Tests conducted in USDA-ARS, Thad Cochran Southern Horticultural Laboratory Poplarville the growth chambers indicated that L. camara yielded the most seeds MS; [email protected] at 80 °F. These results may be also of value for improving breeding Ashley Gann efficiency in other verbens where pollinated flowers set few seeds. College of Agricultural Sciences and Natural Resources knoxville TN; Specified Source(s) of Funding: Department, College, State and/or [email protected] HATCH Private (Association, Foundation, Industry) The Environ- Sandra Reed mental Horticulture Department of the University of Florida, IFAS USDA/ARS Floral & Nursery Plants Research Unit McMinnville TN; Industry/Association Program Name, Award Number: The Southwest [email protected] Florida Water Management District The Florida Nursery Growers and Landscape Association Mark Windham Entomology and Palnt Pathology Knoxville TN; [email protected] Robert Trigiano* 8:30–8:45 am Entomology and Plant Pathology Knoxville TN; [email protected] Studies on Sexual Compatibility Between Eight Nolana Microsatellite or simple sequence repeats (SSRs) are tandem 1-6 bases (Solanaceae) Species repeated motifs, found in coding and noncoding regions of prokary- Rosanna Freyre* otic and eukaryotic genomes. Due to the high nucleotide substitution University of Florida, Gainesville; rfreyre@ufl.edu rate in noncoding regions, SSRs exhibit a high degree of molecular polymorphism. SSRs markers are a powerful genetic tool in plant ge- Amy C. Douglas netics and breeding. Our lab has developed nearly 1000 SSR markers University of New Hampshire Durham NH; adouglas@novaflora.com in flowering dogwood and kousa dogwood, and these markers have Nolana is a large genus endemic to coastal deserts of Peru and Chile been applied to identifying inter- and intraspecific hybrids with these with potential for breeding new herbaceous ornamental cultivars. Stud- two species; identification of cultivars of the two Cornus species, and ies of ploidy level, floral development, sexual compatibility, and seed genomic mapping of C. florida. Two flowering dogwood SSR loci were germination were conducted with eight Nolana species (N. adansonii, used to identify six hybrids from two crosses between flowering and N. aticoana, N. humifusa, N. ivaniana, N. laxa, and N. plicata from kousa dogwood. Five kousa dogwood SSR loci were used to verify Peru; N. elegans, and N. rupicola from Chile). Meiotic chromosome 181 kousa dogwood intra-specific hybrids and two flowering dogwood counts were performed on all species with the exception of N. ivaniana, SSR loci were used to verify four flowering dogwood intra-specific and were found to be diploid (2n=2x=24). Floral development keys hybrids. A dichotomous key was developed for flowering and kousa were constructed based on stigma receptivity and pollen viability at dogwoods using SSR markers. Four SSR loci separated 22 flowering different stages of flower development to correlate morphological ap- dogwood cultivars and lines. In kousa dogwood, five SSR loci were pearance of buds/flowers with artificial pollination success. Artificial used to identify 22 cultivars. The information provided in the two hybridizations (self- intra- and interspecific) were performed within dichotomous keys will be useful for parental and hybrid verification and between each species. Species were generally self-incompatible. and plant patent issues in flowering and kousa dogwood. Lastly, a total Intraspecific compatibility was high with most crosses resulting in of 224 SSR loci were applied to an F2 population of 94 individuals >80% fruit set. Success of interspecific hybridization (2,520 pollina- from a cross between two flowering dogwood cultivars, Appalachian tions) was analyzed based on fruit set, mericarp size and seeds per Spring Cherokee Brave , from which 289 clear genetic markers were mericarp. Thirty-two of 56 possible interspecific crosses set fruit. Within found. These 289 markers are being used to generate 11 linkage groups compatible crosses, reduction in interspecific fertility was generally for flowering dogwood. The data are currently being processed and the evidenced by lower fruit set than in intraspecific hybridizations. Seed first linkage map in flowering dogwood is expected to be completed counts per mericarp were estimated with X-ray analysis, revealing by the end of 2008. that mericarp size is not an effective indicator of seed set. Fewer full Specified Source(s) of Funding: Department, College, State and/or seeds were present in mericarps obtained from interspecific hybridiza- HATCH USDA Agreement # 58-6404-2-0057 tions compared to intraspecific hybridizations. Compatibility between species varied depending on the direction of the cross. Correlation was seen between species’ compatibility and geographic separation of their areas of origin. Germination of hybrid seed was not used as 9:00–9:15 am a reliable measure of compatibility in Nolana because of dormancy Inter-simple Sequence Repeats (ISSRs) Distinguish barriers. Hybrid seed was germinated with 13% success, and verified Genetic Differences in Lilium Species and L. longiflorum compatibility of 22 unidirectional species pairs. ‘Nellie White’ Clones Specified Source(s) of Funding: Department, College, State and/or Ye Sun* HATCH Private (Association, Foundation, Industry) NH00464 In- University of Minnesota Saint Paul MN; [email protected] dustry/Association Program Name, Award Number: American Floral Endowment 2005 Neil Anderson* University of Minnesota Saint Paul MN; [email protected]

1094 HORTSCIENCE, VOL. 43(4), JULY 2008 Adnan Younis low growing highly floriferous small flower series provides whimsical University of Agriculture Faisalabad, Pakistan; [email protected] texture to gardens. The last phenotype of interest is a large plant type with dark green leaves and splotched flowers. Vibrant white patches Lilium longiflorum, Easter lily, has a large genome size (77.1pg/2C on the petals interrupt orange, red, lavender, or pink flower colors. nucleus), ~550x that of Arabidopsis thaliana (0.14pg). The large These colors draw attention to the plants but the flower count is lower genome size of this monocot crop, coupled with repetitive DNA than desired. Challenges encountered during the development of these sequences, makes it difficult to use molecular techniques to identify phenotypes will be discussed. or “fingerprint” lily species, hybrids, and clones. Previous research demonstrated that amplified fragment length polymorphisms (AFLPs) Specified Source(s) of Funding: Department, College, State and/or could not be optimized for consistency and repeatability to obtain reli- HATCH Hatch Project Number ILLU-875-308 able genetic variation assessments of lily species and clones. ISSRs are similar to random amplified polymorphic DNA (RAPDs), differing only by higher annealing temperatures and derivation from microsatellite 9:30–9:45 am regions. An objective of this research was to analyze the effectiveness ‘Raider Gold’ Plains Zinnia, a New Perennial for and stringency of ISSRs to determine genetic differences between lily species and clones. DNA extracts used from previous AFLP analyses (D. Semiarid Landscapes

Zlesak) were incorporated into this ISSR study. Extracts were derived Cynthia McKenney* ORALS–TUESDAY from closely related clones of L. longiflorum ‘Nellie White’, collected Texas Tech University Lubbock TX; [email protected] from growers across years: 2002 [n=11 bulb lots; n=15 bulbs/lot] and 2003 [n=12 bulb lots; n=12 or 15 bulbs/lot]. Hybrid lily species were Rosemary Thomas obtained from commercial growers. Five primers (P808, P810, P811, Texas AgriLife Experiment Station Dallas TX; [email protected] P813, P814), previously shown to exhibit ISSR marker differences in Doug Rohde common tansy (Tanacetum vulgare) and a monocot (Poa), were used to Texas AgriLife Experiment Station Dallas TX; [email protected] identify genetic differences in DNA extracted from lily samples. ISSR primers produced scorable bands and demonstrated sufficient levels Zinnia grandiflora Nutt is commonly known as Plains Zinnia. This of genetic variation between lily accessions to distinguish between native plant is a low growing shrub with a woody taproot common to species and within clones. Unlike AFLPs, ISSRs were also consistent calcareous regions of the Trans-Pecos and Plains regions of Arizona, between replications using the same lily DNA and primers. Statistical Colorado, Kansas, New Mexico and Texas. Plains Zinnia has golden analyses of the ISSR primer results (correlation coefficients to create yellow flower heads composed of fertile ray flowers and three to six similarity matrices, dendrogram derivation from unweighted pair angularly compressed disk flowers that form chaffy achenes. Plains group method or UPGMA) will be presented. These molecular mark- zinnia may be utilized in the urban landscape as an edging plant due ers may aid in establishing relationships between ISSRs and specific to its low stature and mounding habit. ‘Raider Gold’ was selected phenotypes, e.g. non-vernalization-requirement in seed-propagated from an open pollination breeding program of six accessions of Zinnia L. xformolongi, or in marker-assisted selection of the vernalization grandiflora collected throughout Texas. Criteria for inclusion in the requirement in seedlings. program were a tight mounding growth habit, brightly-colored flowers and a prolonged blooming period. ‘Raider Gold’ has a significantly Specified Source(s) of Funding: Department, College, State and/or more compact growth habit with a greater number of branches per plant HATCH than the commercial unnamed cultivar from Plants of the Southwest. In addition, ‘Raider Gold’ has a similar number of flowers per plant resulting in a greater floral density. ‘Raider Gold’ flowers fade to a 9:15–9:30 am softer yellow color and are retained on the plant throughout the fall Novel Impatiens Phenotypes with Market Potential allowing for a prolonged color impact. Daniel F. Warnock* Specified Source(s) of Funding: Private (Association, Foundation, University of Illinois, Urbana; [email protected] Industry) Turner Seed Company Katie Yu University of Illinois, Urbana; [email protected] Impatiens are one of the top selling bedding plants in the United Oral Session 10: Floriculture 1 States. Trials to identify novel phenotypic traits and to improve com- Tuesday, 22 July 8:00–10:00 am Salon 8 mercialization of thrips-resistant impatiens began at the University of Illinois in 2003. With more than 4000 seedlings evaluated annually, the Moderator: Christine Yen, [email protected] objectives of the phenotypic trials are to identify novel plant characteristics and through recurrent selection isolate these into commercially 8:00–8:15 am acceptable cultivars. Breeding goals include flower colors/patterns, number of flowers, flower size, leaf type, growth habit, and branching Timing of Nutrient Termination and Reapplication habit in greenhouse and outdoor trials. Specifically plants with a high Affects Growth, Flower Differentiation, and Flowering of number of large or small flowers, dark green, silver, or variegated a Hybrid Nobile Dendrobium leaves, large upright, spreading, or dwarf habits, and highly branched Christine Yung-Ting Yen* plants are maintained in the breeding lines. Active basic research, Texas A&M University College Station TX; [email protected] hybridization, and selection at the university combined with industry collaboration and evaluations allow for the development of novel Terri W. Starman impatiens phenotypes. Four phenotypes that are of particular interest Texas A&M University College Station TX; [email protected] and currently in trial with commercial companies were developed through the University of Illinois breeding program. A dwarf dark Yin-Tung Wang* green leaf series with several flower colors appears suitable for pot- Texas A&M University Weslaco TX; [email protected] ted plant production. Described as having a ‘New Guinea’ impatiens A study was conducted to investigate the effects of nutrient termina- appearance when mature, this series is seed propagated instead of tion time (1 Aug., 1 Sept., or 1 Oct.) and reapplication stage (at the from vegetative cuttings. A low growing spreading series with pink, beginning, in the middle, immediately after, or 2 weeks after the lavender, and purple toned large flowers fills shady areas quickly. A completion of cooling, or no nutrient reapplication) on growth and

HORTSCIENCE, VOL. 43(4), JULY 2008 1095 flowering of Dendrobium Sea Mary ‘Snow King’, a Dendrobium nobile 8:30–8:45 am Lindl. hybrid. One-year-old liners were potted on 18 Feb. 2006 and Phosphate Budgets for Impatiens Grown in Soilless fertilized with 15N-2.3P-12.9K at 0.67 g·L-1 whenever nutrients were supplied. Plants were grown under 25.1 °C day/22.8 °C night, except Media Amended with Calcined Clays and Diatomaceous during the cooling period. Plants were cooled at 15 °C for 6 weeks Earth with a 12-h photoperiod in a growth chamber for flower induction Rose A. Ogutu* starting on 13 Nov. Interaction between nutrient termination time and Kansas State University Manhattan KS; [email protected] reapplication stage was non-significant, and reapplication stage had only minor effect on growth and flowering. Regardless of nutrient Kimberly A. Williams reapplication stages, nutrient termination on 1 Oct. resulted in taller Kansas State University Manhattan KS; [email protected] plants with more nodes, leaves remaining, flowering nodes, and total In two greenhouse experiments, phosphate budgets were created for flowers, as well as fewer aborted flowers than those being terminated Impatiens wallerana Hook.f. cv. Tempo Rose grown in peat-based earlier. Nutrient supply until 1 Oct. did not lead to differences in root media with various amounts of three absorbent components: time required for anthesis but extended the time required to reach diatomaceous earth (DE) and the calcined clays Terra green mont- full flowering by 1.5 d. Histological examinations of lateral buds, morillonite (TG) and Attasorb attapulgite (AS). In Expt. 1, the two taken 4 weeks into cooling, showed that nutrient termination on 1 clays were incorporated (by volume) into a mix of 5 peat : 2 perlite : 3 Aug. resulted in larger flower primordia than those terminated on 1 absorbents, with the 30% absorbent components consisting of 0%, 5%, Oct., indicating that buds were more mature and flowers differentiated 10% or 20% clay + DE. In Expt. 2, clays and DE were incorporated earlier or faster with an earlier nutrient termination. No aerial shoot at 0%, 5%, and 10% into peat and perlite mixes. Control plants were formation or reversion of reproductive to vegetative buds occurred. grown in 7 peat:3 perlite in both experiments. Physical properties The results suggest that nutrient termination on 1 Oct. produce the of all mixes were characterized. Phosphate was applied as soluble best two-year-old flowering pot plants and no nutrient reapplication -1 fertilizer at rates of 0, 5, 15, and 45 mg·L PO4-P. Phosphorous was is needed for flowering. recovered from leachate, whole shoots, and root media to create the Specified Source(s) of Funding: Department, College, State and/or budgets. The absorbent materials DE, TG and AS themselves had initial HATCH Private (Association, Foundation, Industry) Department of amounts of 259, 351, and 737 mg P/kg, respectively. The media with Horticultural Sciences, Texas A&M University. The American Orchid absorbent components retained 18% more PO4-P compared to the 7 Society. The Fred C. Gloeckner Foundation, Inc. peat: 3 perlite control in Expt. 1. The controls leached 19% (Expt. 1) and 23% (Expt. 2) of total PO4-P applied compared to 13 to 15% from treatments with absorbent components. Though DE has been shown to have no PO -P sorption capacity, this absorbent material 8:15–8:30 am 4 resulted in similar PO4-P retention during production as the calcined Nutrient Leaching from Propagation Media and clays, apparently through a physical as opposed to chemical sorption -1 Fertilizer Formulations mechanism. However, at PO4-P fertilizer rates < 45 mg·L , impatiens Angelica Cretu* growth was lower in DE treatments compared to clay-containing University of Florida, Gainesville; acretu@ufl.edu treatments and the 7 peat: 3 perlite control, suggesting that DE may sequester PO4-P and render it less available for plant uptake. Even Paul Fisher* at relatively low percentages of 10% and less in soilless root media,

University of Florida, Gainesville; pfisher@ufl.edu TG and AS calcined clays significantly reduced PO4-P leached during greenhouse production. Leaching of fertilizer from propagation media can impact plant and water resource quality. The objective was to quantify how nutrient Specified Source(s) of Funding: Private (Association, Foundation, leaching curves differed between (a) seven commercial media, and Industry) Gloeckner Foundation (b) a peat/perlite research medium blended with five fertilizer types (resin-coated 18-2.6-10, water soluble 20-2.7-11.7, granular 100%

NO3-N formula 6-0.8-3.3, granular 50% NH4-N/50% NO3-N 6-0.8-3.3, 8:45–9:00 am granular 50% urea/25% NH4-N/25% NO3-N 6-0.08-3.3) applied at 0.18 g·L-1 of N. Media were placed into 128-count propagation trays Gradation and Nitrogen Release of Zein-based Bioplastic and were drenched with 542 mL of deionized water twice daily for two Pots weeks. Leachate and media (plug squeeze) samples were collected to Matthew Helgeson* quantify the change in electrical conductivity (EC), pH and individual Iowa State University, Ames; [email protected] nutrients. Container capacity (CC) ranged from 16.0 to 17.8 mL per 24.9 mL cell for commercial media, and equaled 17.2 mL for the William Graves research medium. Leachate averaged 0.3 (commercial media) or 0.2 Iowa State University, Ames; [email protected] CC (research media) per drench for a total of 4.5 to 4.8 CC. Leach- -1 David Grewell ate-EC peaked at 2.0 to 5.7 mS·cm after 0.5 CC leached, followed Iowa State University, Ames; [email protected] by decreasing EC with increased leaching to a minimum of 0.3-0.5 mS·cm-1 after 1.5 CC leached. Leachate-EC for research media differed Srinivasan Gowrishankar between fertilizer formulations, from 1.5 to 2 mS·cm-1 for granular Iowa State University, Ames; [email protected] and water soluble fertilizers. In contrast, resin-coated fertilizer and no fertilizer treatments had leachate-EC levels of 0.6 and 0.4, respectively. Degradation and longevity of bioplastic pots made from the corn The maximum EC for research media also occurred after 0.5 CC was protein, zein, were determined. Pots filled with irrigated horticultural leached and decreased until 1.5 CC leached. In general, nutrients in media showed degradation and structural failure within three months. the media were nearly completely removed after 1.5 CC leached, with The extent of degradation, assessed via weight loss of empty pots, the exception of resin-coated fertilizer. Because high water volume is was 90% greater among pots that had been filled with a peat-based often applied in propagation, these results emphasize the importance medium than among pots filled with perlite. Pots that had been irri- of irrigation management to reduce runoff. gated every 4 days lost 34% more weight than pots irrigated every 2 days. During a second experiment designed to simulate the practice of Specified Source(s) of Funding: Department, College, State and/or direct-planting horticultural commodities into the landscape without HATCH Private (Association, Foundation, Industry) removing these biodegradable pots, planting into drained field soils resulted in 76% more loss of pot weight than planting into saturated field soils. This suggests that aerated conditions enhance the microbial

1096 HORTSCIENCE, VOL. 43(4), JULY 2008 activity that we postulate fosters degradation. Leachate from these high porosities. We are focused on the root zone, to calibrate sensor pots contained up to 250 mg/kg nitrogen. We conclude that nitrogen performance with daily plant water use. Using a modified tension is released from the zein protein as the pots degrade because leachate table, we calibrated various Ech20 sensors in five commercial soil- from conventional plastic pots treated identically contained nitrogen less substrates, with varying physical properties and air contents, by at no more than 20 mg/kg. Further research is needed to demonstrate applying pressures from 1 to 100 kPa, the range in which most PAW the horticultural benefits of nitrogen release from zein-based bioplastic is held in soilless substrates. By measuring the water expressed from pots and to enhance the longevity and strength of these pots for crops 10 replicate columns at each pressure and simultaneously measuring with production cycles of more than a few months. the output from a sensor embedded in each column, we developed a series of calibration curves for each substrate and sensor type. All Specified Source(s) of Funding: Private (Association, Foundation, regression curves of sensor output (mV) versus volumetric water Industry) -Department, College, State and/or HATCH Industry/As- (cm3/cm3) had r2 values greater than 0.84 (P < 0.001; n = 30). Con- sociation Program Name, Award Number: Horticulture Research fident that capacitance sensors can provide precise measurements of Institute PAW in these soilless substrates, we are now using these calibrations to more accurately schedule irrigations using wireless sensor networks 9:00–9:15 am in nursery and greenhouse operations. More precise applications of water have been shown to conserve water, and reduce nutrient leaching Comparison of Total Chlorophyll Content with and runoff from container-production operations. ORALS–TUESDAY Chlorophyll Meter Readings in Oxalis regnellii Specified Source(s) of Funding: Department, College, State and/or Chad Miller* HATCH Private (Association, Foundation, Industry) Chesapeake Bay Cornell University Ithaca NY; [email protected] Trust / Horticultural Research Institute/Maryland Experiment Station William Miller / Maryland Cooperative Extension Cornell University Ithaca NY; [email protected]

Jed Sparks 9:30–9:45 am Cornell University Ithaca NY; [email protected] Improving the Postharvest Life of Woody Cut Stems The Shamrock Plant (Oxalis regnellii), a specialty potted bulb crop, is Lane Greer grown for its clover-like leaves and white flowers for the St. Patrick’s Portland State University Portland OR; [email protected] Day holiday. However, interveinal chlorosis is a common problem in commercial production and is purported to be an iron (Fe) defi- John Dole* ciency. Iron is a major component in many photosynthetic pigments North Carolina State University Raleigh NC; [email protected] and Fe deficiency leads to a decreased amount of chlorophylls and subsequent chlorosis. The SPAD-502 is a non-destructive instrument We determined the optimum postharvest handling protocols to increase used to measure the relative chlorophyll concentration in leaves. The vase life for nine species of woody cut stems, including Buddleia objective of this study was to establish a relationship between total davidii ‘Royal Red’, Buxus sempervirens, Hydrangea quercifolia, Ilex chlorophyll content with SPAD-502 meter readings in oxalis leaves. crenata, Ilex ‘Nellie R. Stevens’, Ligustrum sinense, Myrica cerifera, Total chlorophyll concentrations were measured in oxalis leaves hav- Pyracantha coccinea, and Viburnum tinus ‘Spring Bouquet’. The anti- ing different levels of greenness using DMSO and were compared to ethylene agent 1-methylcyclopropene (1-MCP) and 50 °C distilled SPAD-502 meter readings of the same leaves. These data indicated (DI) water produced the longest vase life for Buddleia davidii. The a positive correlation between SPAD-502 meter readings and total 10% sucrose pulse and 1-MCP resulted in the longest vase life for V. chlorophyll concentrations. tinus of 15 to 13.5 days, respectively, while vase life of stems placed in 50 °C DI and tap water was significantly shorter at 8.8 and 9.0 d, Specified Source(s) of Funding: Department, College, State and/or respectively. Holding stems in 4% sucrose yielded a vase life of 13.8 HATCH Florida Fish and Wildlife Conservation Commission days. Ambient (20 °C) DI water was optimal for M. cerifera (9.9 weeks) while stems pulsed with 10% sucrose experienced the shortest vase life of 2.2 weeks. As with Viburnum tinus, foliage was discolored by 9:15–9:30 am the sucrose pulse treatment. No pre-treatment extended the vase life of Calibration of Capacitance Sensors to Precisely Measure Buxus sempervirens, H. quercifolia, I. crenata, I. ‘Nellie R. Stevens’, Plant-Available Water in Soilless Substrates L. sinense, or P. coccinea. There was no difference in vase life of stems from any of the nine species held in low solution pH (4.5) compared Felix R. Arguedas* with those held in higher solution pH (6.1). For Experiment 2, stems University of Maryland College Park MD; [email protected] were held in 0%, 2%, or 4% sucrose (+ antimicrobial agent) with or John D. Lea-Cox without foam. The only species not adversely affected by foam was University of Maryland College Park MD; [email protected] Buxus sempervirens. Species that performed best in 0% sucrose included Buxus sempervirens and M. cerifera; in 2% sucrose included Buxus Andrew G. Ristvey sempervirens, I. ‘Nellie R. Stevens’, L. sinense, and V. tinus; and in University of Maryland Queenstown MD; [email protected] 4% sucrose included I. ‘Nellie R. Stevens’ and V. tinus. Sucrose had no effect on Buxus davidii, H. quercifolia, I. crenata, or P. coccinea. David S. Ross University of Maryland College Park MD; [email protected] Specified Source(s) of Funding: Private (Association, Foundation, Industry) Department, College, State and/or HATCH Industry/As- The nursery and greenhouse industry requires a more precise method sociation Program Name, Award Number: Association of Specialty to schedule irrigations, since current techniques are subjective and Cut Flower Growers contribute to water and nutrient leaching and runoff from production areas. We need to improve water management practices, to increase interception efficiency and monitor leaching fractions from each irrigation application. We are using Ech20 capacitance sensors (Decagon 9:45–10:00 am Devices, Pullman, WA) to accurately sense plant-available water Response of Four Rose Rootstocks to Chloride Versus (PAW) in soilless substrates, as these may provide a reliable and af- Sulfate Salinity fordable method to develop sensor networks for large-scale growing Genhua Niu* operations. Other sensing methods (tensiometers, gypsum blocks) have been shown to be less precise in these substrates because of Texas AgriLife Research El Paso TX; [email protected]

HORTSCIENCE, VOL. 43(4), JULY 2008 1097 Denise S. Rodriguez rapidly when substrate moisture content was around 15% (substrate Texas A&M University System El Paso TX; [email protected] moisture potential of 2 MPa). Leaf gas exchanges, photosynthetic rate (Pn), transpiration rate (E), and stomatal conductance (gs), of all species Salt-tolerant garden roses are needed for arid and semi-arid regions decreased rapidly when substrate moisture contents decreased below where high quality water supply is limited and soil salinization often 20%. After re-irrigation, RWC recovered rapidly but gas exchanges occurs. This study evaluated growth and ion uptake of four rose recovered slowly, regardless of species. The differences in physi- rootstocks (Rosa × ‘Dr. Huey’, R. fortuniana, R. multiflora, and R. ological responses to drought treatments among species were smaller odorata) in a greenhouse irrigated with saline solutions with domi- compared to growth, regardless of species. Based on growth reduction, nant salts of either chloride or sulfate. After 16 weeks of treatment, R. fortuniana may be more tolerant to drought stress, followed by R. elevated salinities reduced growth of all species but the magnitude ‘Dr. Huey’, R. multiflora, and R. odorata in descending order. varied with species and dominant salt type. At both moderate (3.9 dS/m) and high salinities (7.9 to 8.2 dS/m), chloride-dominated salinity led to a greater growth reduction in R. fortuniana. At high salinity dominated by sulfate, R. odorata had a greater growth reduction than 10:15–10:30 am the other three species. For R. multiflora, growth was reduced more in Poinsettia (Euphorbia pulcherrima Willd.) In Vitro chloride dominated salinity at high salinities but no differences were Proliferation found in growth between the two salt types at moderate salinity. All Dinum Perera* species limited Na transport to shoots except for R. odorata, which was evidenced by higher Na concentrations in stems and leaves than Mississippi State University Mississippi State MS; [email protected] those of other species. However, root Na concentration was highest Brian Trader in R. multiflora, followed by R. odorata. Root Na concentrations in R. Mississippi State University Mississippi State MS; [email protected] fortuniana and R. ‘Dr. Huey’ were similar. Although all species had similar leaf Cl concentrations at high salinity dominated by chloride, Mengmeng Gu R. fortuniana had the most severe foliar salt damage, indicating that R. Mississippi State University Mississippi State MS; [email protected] fortuniana is simply less tolerant to high tissue Cl concentrations than Euphorbia pulcherrima, poinsettia, micropropagation and in vitro- other species. At moderate salinity, all species had acceptable visual proliferation is extensively practiced by poinsettia producers and quality. At highest salinities, the appearance of all species declined researchers. Slow plantlet growth rate, few micro shoots per explant with typical salt damage on lower, older leaves. In summary, the and slow root growth are restrictions of in vitro propagation of poin- performance of the four rootstocks responded differently to salinities settia. Greenhouse grown explants (apical buds and axillary buds) and dominant salt type. were placed on Murashige-Skoog (MS) basal medium supplemented Specified Source(s) of Funding: Federal competitive The present re- with various concentrations (4 µM-12 µM) of Indole-3-acetic acid search is supported by the FY07-Federal Initiative Designing Foods (IAA) and 6-benzylaminopurine (BA) in order to optimize shoot for Health through the Vegetable & Fruit Improvement Center, Grant proliferation and rooting of poinsettia in vitro. Explants placed on No. TAES 06-118409. media containing combination of 12 µM of IAA and BA produced the highest amount (mg/fresh weight) of red callus and greatest number of micro buds after one month. Subculturing of red callus in the same medium produced more callus and number of micro buds. Regenerated Oral Session 11: Floriculture 2 micro buds produced greater number of micro shoots on a medium with only BA. Increased concentration of BA from 4 µM to 12 µM Tuesday, 22 July 10:00 am–12:00 pm Salon 8 increased the number of micro shoots per explant. Four month old Moderator: Genhua Niu, [email protected] micro shoots rooted on MS basal medium without any plant growth regulator (PGR) after one month, however addition of IAA into the medium increased rooting efficiency. Incorporation of PGRs into mi- 10:00–10:15 am cropropagation media in proper concentrations at different stages of in Relative Drought Tolerance of Four Rose Rootstocks vitro plantlet growth enhanced rapid callus formation and accelerated shoot and root growth. Optimization of PGR concentrations during Genhua Niu* poinsettia micropropagation helped resolved previous restrictions of Texas AgriLife Research El Paso TX; [email protected] in vitro poinsettia proliferation. Denise S. Rodriguez Specified Source(s) of Funding: Department, College, State and/or Texas A&M University System El Paso TX; [email protected] HATCH Drought-tolerant garden roses are needed in arid and semi-arid regions where irrigation water is scarce. The growth and physiological responses to mild and severe drought stresses of four rose rootstocks (Rosa × ‘Dr. 10:30–10:45 am R. fortuniana, R. multiflora R. odorata Huey’, , and ) were quantified in High Temperature Inhibition of Phalaenopsis Flowering a greenhouse. Plants grown in 12-L containers were well-irrigated or mild-drought stressed cyclically for 10 weeks. Severe drought stress Linsey Newton* was imposed on all plants in the drought treatment at the end of the Michigan State University, East Lansing; [email protected] experiment. Final dry weights (DW) of all plant parts and leaf area Erik Runkle in R. ‘Dr. Huey’ and R. fortuniana were not affected by the drought Michigan State University, East Lansing; [email protected] treatments except for a small root DW reduction in R. ‘Dr. Huey’. However, DW of R. multiflora and R. odorata decreased by 20% and Phalaenopsis and related genera are among the most popular and 30%, respectively, compared to the control. Root to shoot ratios in R. widely grown potted flowering plants in the United States, Europe, ‘Dr. Huey’, R. fortuniana and R. multiflora were not affected by the and Asia. Day temperatures greater than 26 °C inhibit inflorescence drought treatments, while that of R. odorata increased by 180%. Leaf initiation, while lower temperatures can induce flowering of mature relative water content (RWC) of R. ‘Dr. Huey’, R. fortuniana, and plants. The effects of various durations of daytime exposure to 29 °C R. multiflora decreased rapidly when the substrate moisture content were studied to determine the duration required each day to inhibit decreased below 20%. RWC of R. odorata decreased slowly due to flowering of four Phalaenopsis hybrids. Five durations at 29 °C were smaller total leaf area and hence slower water loss compared to other used: 0, 4, 8, 12, or 24 h per day. The temperature during the remaining species. Predawn leaf water potentials in all species started to decrease period of each day was 20 °C. In each treatment, the period at 29 °C was centered at the middle of a 16-h photoperiod (0600 to 2200 HR)

1098 HORTSCIENCE, VOL. 43(4), JULY 2008 provided by shaded sunlight (maximum irradiance of 350 µmol·m- Specified Source(s) of Funding: Department, College, State and/or 2·s-1) and supplemental lighting from high-pressure sodium lamps. HATCH Plants were grown at these temperature treatments for 20 weeks and flowering characteristics were measured. As expected, all plants placed at constant 20 °C developed inflorescences while plants exposed to 11:00–11:15 am constant 29 °C did not. Four hours at 29 °C (from 1200 to 1600 HR) did not inhibit inflorescence formation for any of the hybrids. Eight Efficacy of Acquired Stress Tolerance for Improving or twelve hours at 29 °C prevented the formation of inflorescences Landscape Survivability of Petunia on Phalaenopsis ‘Mosella’ and ‘Explosion’. In contrast, Phalaenopsis Jennifer Mader* Baldan’s Kaleidoscope ‘Golden Treasure’ and Doritaenopsis New- Louisiana State University Baton Rouge LA; [email protected] berry Parfait developed inflorescences when exposed to 29 °C for 8 or 12 h, but inflorescence emergence was delayed. For Phalaenopsis Jeff Kuehny Baldan’s Kaleidoscope ‘Golden Treasure’, 8 or 12 h at 29 °C delayed Louisiana State University AgCenter Baton Rouge LA; [email protected] inflorescence emergence by 4 or 6 weeks, respectively; both high tem- Greenhouse grown bedding plants may be easily monitored and allevi- perature durations delayed inflorescence emergence on Doritaenopsis ated of heat or drought stress. However, plants entering postproduction Newberry Parfait by 5 weeks. These results indicate that the duration in the market and eventually the landscape often face an inconsistent ORALS–TUESDAY of high temperature exposure required to prevent flowering depends environment and can be subject to long periods of water stress and on the hybrid grown. enduring high temperatures. Plants that are preconditioned (acquired Specified Source(s) of Funding: Private (Association, Foundation, stress tolerance) may greatly improve postproduction marketability and Industry) survival in the landscape when exposed to a challenging environment. The objective of this study was to determine the efficacy of acquired temperature tolerance for improving landscape survivability using 10:45–11:00 am Petunia × hybrida as a model plant. Greenhouse grown ‘Midnight’ Dreams subjected to heat stress treatments of 30 °C, 35 °C, and 40 °C Environmental Influences on Flowering of Angelonia showed that dry weights of plants harvested from the three temperature angustifolia treatments increased over a 5-week period, but plants grown at 40 °C Jennifer Boldt* weighed significantly less than those grown in the other temperatures. University of Florida, Gainesville; jkboldt@ufl.edu Flower count increased at 30 °C and 35 °C after 4 weeks, while decreasing at 40 °C. Plants grown at 30 °C produced a higher flower James Barrett count than at 35 °C. Flower size was significantly higher in petunias University of Florida, Gainesville; jbarrett@ufl.edu grown at 30 °C than at 35 °C or 40 °C. However, once transplanted to the landscape, the quality of plants grown in 30 °C declined over Rosanna Freyre a 3-week period, while plants grown at 40 °C showed the greatest University of Florida, Gainesville; rfreyre@ufl.edu improvement after the third week. James Gibson Specified Source(s) of Funding: Department, College, State and/or Conrad Fafard, Inc. Anderson SC; [email protected] HATCH Kenneth Quesenberry University of Florida, Gainesville; clover@ufl.edu 11:15–11:30 am A preliminary cultivar screen at the University of Florida indicated more than three weeks difference in time to first flower among com- Development of a Rapid and Effective Screening Method mercial Angelonia angustifolia cultivars in production. In landscape for Basal Stress Tolerance of Petunia trials, cultivars varied in their ability to flower throughout the summer Miao Liu* months. The objective of this research was to screen eight cultivars Louisiana Sate University Baton Rouge LA; [email protected] of Angelonia from four commercial series to quantify differences in flowering during greenhouse production and in the landscape. Jeff Kuehny* Greenhouse experiments were initiated in January, March, and June Louisiana State University AgCenter Baton Rouge LA; [email protected] 2007 to determine the effect of season on time to flower. Plants were grown in 2.2-L pots with 12 reps per cultivar. Average 24-hour Two of the greatest impediments to bedding plant growth and develop- temperatures were 21.3 °C, 23.3 °C, and 28.0 °C, and average daily ment are high temperature stress and drought stress. The objective of light integrals were 20.3, 21.9, and 18.2 mol·m-2·d-1, respectively. this study was to develop a rapid and effective protocol for screening The number of days to first flower decreased in all cultivars in each petunia for basal heat and/or drought tolerance by measuring seedling successive season. The quickest flowering cultivar was ‘AngelMist growth sensitivity (SGS). Three types of substrate (white or black Dark Lavender’ at 41, 26, and 24 days. The slowest was ‘Angelface filter paper, or a transparent cellulose film) were tested for their abil- White’ at 59, 50, and 40 days. To determine the effect of plant date ity to sustain germination, support seedling growth and allow for on summer landscape performance cultivars were planted in outdoor quantifying growth. The clear cellulose film provided for the best ground beds three times, at four week intervals (PD1 = 4/4/07, PD2 measurement and uniform germination and growth of seedlings. Seeds = 5/2/07, and PD3 = 5/30/07) with 12 plants per cultivar per plant were germinated in Petri dishes and then subjected to polyethylene date. Plant growth and flowering data were collected 10 weeks after glycol at 0.0(control), -0.2, -0.4, -0.6, or -0.8 Mpa osmotic pressure to planting. Inflorescence number per plant decreased in all cultivars determine SGS protocol for drought stress. Hypocotyl and/or radicle with each successive planting. Three cultivars were significantly dif- length were measured by using digital imaging prior to and follow- ferent between PD1 and PD2, and five between PD1 and PD3. Flower ing treatments. The results indicated that four days after treatment, number per inflorescence decreased with each successive planting. the seedling growth was most significantly weakened by the osmotic Six cultivars were significantly different between PD1 and PD2, and pressure of -0.8 Mpa when compared to all other treatments. Thus, seven between PD1 and PD3. Flower size was not affected by plant the most effective protocol for screening petunias for drought stress date. Flower coverage was significantly lower in four cultivars between by SGS is at -0.8 Mpa four days after germination. PD1 and PD2, and in six between PD1 and PD3. PD1 was the best Specified Source(s) of Funding: Private (Association, Foundation, planting date and cultivars ‘AngelMist Purple Stripe’ and ‘Angelface Industry) White’ produced the best summer floral display.

HORTSCIENCE, VOL. 43(4), JULY 2008 1099 11:30–11:45 am = 75% of plant infected, 3 = 50% of plant infected, 2 = 25% of plant Water-Based Cold Protection of Foliage Plants in infected, 1 = healthy plant). Four cuttings per 4.5 pots were grown as recommended. During the third week of rating, plants treated with Shadehouses Sil-Matrix, Heritage alternated with Sil- Matrix, or water showed Robert Stamps* symptoms of powdery mildew at a rapid rate. This trend continued University of Florida, Apopka; rstamps@ufl.edu through week six. Miniature roses treated with Kaligreen, Heritage alternated with Foshpite, or Heritage alternated with Kaligreen were Lawrence Parsons not as susceptible to powdery mildew. Disease incidence increased, University of Florida, Lake Alfred; lparsons@ufl.edu however, for all plants in all treatments through week 5. Seenivasan Natarajan Specified Source(s) of Funding: Private (Association, Foundation, University of Florida, Apopka; vasan@ufl.edu Industry) Jianjun Chen University of Florida, Apopka; jjchen@ufl.edu Water-based cold protection systems for ornamental foliage plant Oral Session 12: Ornamental Plant Breeding 2 production in shadehouses were evaluated for efficiency and water usage at three commercial locations (L1, L2, and L3) in Florida. L1 Tuesday, 22 July 10:30 –11:45 am Salon 10 used a two-stage thermostat-controlled under-the-bench system with Moderator: Tim Rinehart, [email protected] mist nozzles on 25-cm aboveground risers combined with overhead retractable heat curtains. L2 and L3 had seasonally applied polyethylene 10:30–10:45 am film cladding and manually controlled irrigation systems. L2 used a low-pressure fog system on 25-cm aboveground risers spaced among Using the “Gene-deletor” Technology and Breeding the plants in one shadehouse and over-the-roadway mist nozzles in Techniques to Reduce Invasiveness of Exotic Ornamental a second shadehouse. L3 used a low-pressure among-the-plants fog Crops system. Temperature data loggers were placed outside and inside the northwest sections of the shadehouses. The systems were evaluated Yi Li* during freeze events in 2007 and 2008. Three of the four systems University of Connecticut Storrs CT; [email protected] successfully kept the shadehouse temperatures above critical chilling Invasive plants are one of the most devastating ecological problems temperatures for all of the foliage plants. The fourth system, used at in the 21st century, causing a $35 billion loss per year to the economy L3, protected all subtropical crops but one sensitive tropical crop, in the; alone. More than 50% of all invasive plant species and 85% jungle drum palm (Carludovica sp.), sustained chill injury. At L1, of invasive woody plants were introduced originally for ornamental with sprinklers on, the air temperatures recorded inside the shadehouse and landscape use. Because many invasive ornamental plants are were approximately 17 °C warmer than outside. At L2, while both commercially important and widely utilized for various purposes, the fog and mist systems maintained warmer temperatures inside the completely banning their use and prohibiting their imports is not shadehouse, the fog system maintained higher temperatures than the practical. However, currently used methods to control the spread of mist system while applying 87% less water. At L3, water usage and invasive plants are ineffective, expensive, or environmentally prob- inside temperatures were lower (5% and 3 °C, respectively) than lematic. Using both traditional (e.g., mutational breeding techniques) those at L2 using the same low-pressure fog nozzles. While provid- and modern (i.e.., the “gene-deletor” and “super-sterile” technologies) ing approximately the same level of cold protection, the amount of approaches, we are producing non-invasive cultivars of economically water used per unit area was much less with fog systems than with important but highly invasive ornamental plants. In this presentation, the mist systems. However, even the mist systems conserved water I will describe the “gene-deletor” and “super-sterile” technologies compared to conventional sprinkler irrigation systems. Results show we have recently developed, discuss their applications in addressing the potential of water-based approaches for maintaining shadehouses invasive problems of ornamental crops, and provide a progress report above chilling temperatures during freeze events. of our work toward the production of non-invasive forms of Euony- Specified Source(s) of Funding: Department, College, State and/or mus alata and Japanese barberry, two highly invasive but extremely HATCH Southwest Florida Water Management District, Florida popular ornamental crops. Agricultural Experiment Station Specified Source(s) of Funding: Department, College, State and/or HATCH Federal competitive Federal Program Name, Award Number: USDA and DOE 11:45–12:00 pm Efficacy of Biopesticides on Powdery Mildew of Miniature Roses 10:45–11:00 am Mary Beth Robichaux* Improving Caladium, Gerbera, and Lisianthus for Better Louisiana State University Baton Rouge LA; [email protected] Disease Resistance and Stress Tolerance Jeff Kuehny Zhanao Deng* Louisiana State University AgCenter Baton Rouge LA; [email protected] University of Florida Wimauma FL; zdeng@ufl.edu Supplemental silicon can increase plant growth and crop quality, Brent Harbaugh stimulate photosynthesis, and decrease disease pressures. Powdery University of Florida Wimauma FL; harbaugh@ufl.edu mildew, Sphaerotheca pannosa, is a common problem for miniature Natalia Peres roses among other ornamental plants. The objectives of this experi- University of Florida Wimauma FL; nperes@ufl.edu ment were to determine the efficacy of weekly spray applications of biopesticides Sil-Matrix (potassium silicate), Fosphite (phosphoric Improving disease resistance and stress tolerance has become a major acid), Kaligreen (potassium bicarbonate), and Manniplex Traffic breeding objective in many ornamental plant improvement programs (chelated Si) on powdery mildew of Rosa chinensis minima ‘Alto’ worldwide. Use of new cultivars with improved disease resistance and ‘Sonja’ compared to the efficacy of a commonly used standard and/or stress tolerance can help growers enhance product (tuber, plant, pesticide Heritage. Disease incidence was measured by a visual or flower) quality, reduce production costs and energy consumption, quality rating (5 = 100% of plant infected with powdery mildew, 4 lessen potential negative impacts of agrochemicals to the environment,

1100 HORTSCIENCE, VOL. 43(4), JULY 2008 and add to better sustainability. In the past several years, we have de- 11:15–11:30 am voted a major effort toward this objective in several floricultural crops Increasing Phenotypic Diversity in Hydrangea including caladium, gerbera, and lisianthus. Five and seven sources of host plant resistance have been identified for fusarium tuber rot and macrophylla Using Targeted and Random Mutation pythium root rot, respectively, two very destructive and economi- Stephen Greer* cally important diseases in caladium. Using the identified sources of USDA, Agricultural Research Service Poplarville MS; stephen.greer@ars. resistance, new elite breeding lines have been developed. This effort usda.gov is being continued to pyramid multiple disease resistance traits into Jeffrey Adkins future cultivars. Two sources of resistance to powdery mildew, the most destructive disease in pot and garden gerbera, have been found, Stephen F. Austin State University Nacogdoches TX; [email protected] and two resistant cultivars have been released. More colors and plant Sandra Reed types are being added to the powdery mildew resistant series of gerbera USDA/ARS Floral & Nursery Plants Research Unit McMinnville TN; cultivars. Cold tolerance has been confirmed in a number of commercial [email protected] caladium cultivars and has been incorporated in elite breeding lines, which are expected to help extend the growing season and increase the Timothy Rinehart USDA, Agricultural Research Service Poplarville MS; tim.rinehart@ars. geographical regions for caladium use. Thirteen new F1 heat-tolerant lisianthus cultivars have been released in two series, UF Savanna and usda.gov ORALS–TUESDAY UF Double Joy. Seedlings of these cultivars can be grown at 82 °F to We have developed an improved in vitro procedure for germinating 88 °F without rosetting, making them able to flower uniformly and viable Hydrangea macrophylla seed. Consequently, we have broad- year-round, even under warm climate conditions. ened our capability for selecting germlings that in the past may have Specified Source(s) of Funding: Department, College, State and/or initially died in nature or, were passed over (in breeding programs) in HATCH N/A Industry/Association Program Name, Award Number: favor of more hearty, faster growing seedlings. This has proven useful N/A Federal Program Name, Award Number: N/A Industry/Associa- to increase phenotypic diversity in chemical (e.g. EMS) and radiation Program Name, Award Number: The Florida caladium growers tion (e.g. X-ray) mutated seeds since eventual survival of germplasm association, the Fred C. Gloeckner Foundation, etc. generated by these methods has been optimized. Likewise, our added capability to make regenerative (leafy) callus has allowed us to pursue targeted mutation via RNAi and enhanced gene expression. As a result, 11:00–11:15 am we have targeted seeds, young germlings, and callus for transformation by Agrobacterium tumefaciens vector constructs with the aim of The Inhertiance of Race-specific Black Spot Resistances modifying hormone levels and enzymes known to produce desirable in Tetraploid Roses phenotypic traits. The success of our efforts in H. macrophylla will Vance M. Whitaker* serve as a valuable tool and model for increasing the diversity of University of Minnesota St. Paul MN; [email protected] desirable phenotypic traits in the germplasm of other economically important ornamental crops. Stan C. Hokanson* University of Minnesota St. Paul MN; [email protected] Specified Source(s) of Funding: Federal competitive Federal Program Name, Award Number: National Science Foundation under Grant No. Black spot disease, incited by the fungus Diplocarpon rosae Wolf, is DEB-0423704, Central Arizona - Phoenix Long-Term Ecological the most serious disease of garden grown roses in the world. Race- Research (CAP LTER). specific resistance is well documented in this pathosystem. Two major resistance genes (Rdr1 and Rdr2) effective against German races of this pathogen have been identified and introgressed from Rosa multiflora 11:30–11:45 pm into modern roses. The objective of this study was to determine the inheritance of resistance to three North American races of D. rosae Genetic Diversity Estimates for Dichroa Species in tetraploid rose cultivars. Cultivars resistant to North American Timothy Rinehart* races A, B, and C were hybridized to multiple susceptible parents. USDA, Agricultural Research Service Poplarville MS; tim.rinehart@ars. Progenies were tested by detached leaf inoculation, in which sus- usda.gov ceptibility was indicated by lesion development and the formation of Sandra Reed spore-bearing acervuli. Resistances to races A and C both segregated USDA/ARS Floral & Nursery Plants Research Unit McMinnville TN; approximately 1:1 in multiple F1 progenies, indicative of single dominant genes in simplex (Rrrr) configuration according to random [email protected] chromosome assortment. Molecular marker analyses indicate that The genus Dichroa consists of 12 species of flowering plants in the the gene conferring resistance to race C resides at a different locus family Hydrangeaceae, native to eastern and southeastern Asia. They than Rdr1 and Rdr2. In crosses with ‘Folksinger’ as a female parent, are deciduous shrubs growing 1 to 3 meters tall in full sun or light segregation ratios were skewed for resistance to race A, with fewer shade and may exhibit evergreen growth habit in warmer climes. plants in the resistant class vs. the susceptible class. In crosses between Flowers are hermaphroditic and similar to that of the related genus the parents ‘Folksinger’ and ‘Love and Peace’, progeny resistant to Hydrangea but lacking the sterile florets or large showy petals. Flow- both races A and C were recovered, demonstrating gene pyramiding ers cluster at terminal ends of branches but are also frequent along the as an effective method for conferring broader black spot resistance length of the branch from axillary buds. The fruit is a glossy metallic in rose. Segregation of resistance to race B exhibited a continuous purple-blue berry. Dichroa cultivars are not yet widely available but distribution indicative of multigenic control. Resistance appeared there is considerable interest in intergeneric hybrids between Dichroa partial, with low levels of lesion development and sporulation occur- febrifuga and Hydrangea macrophylla. Controlled crosses and open ring for even the most resistant seedlings. These results will afford pollination have produced viable fertile offspring suggesting that these valuable information to rose breeders and provide a basis for further genera could freely interbreed in nature if native ranges overlapped. genetic studies. To better understand the genetic diversity within Dichroa, we col- Specified Source(s) of Funding: Department, College, State and/or lected tissue samples from commercially available plants and those HATCH under development as ornamental cultivars. Many of these plants can be traced to a few wild-collected seeds suggesting most commercially available Dichroa cultivars are derived from a few seed sources. We also report significant variation in genome size, which

HORTSCIENCE, VOL. 43(4), JULY 2008 1101 may not adversely impact fertility of intergeneric hybrids, but could percentage of edible yield or mean nut weight and losses were inter- have profound effects on for future breeding. Some F1 intergeneric mediate in severity for other parameters when comparing early and hybrids lack robust expression of H. macrophylla traits, presumably late season WHF-infested walnuts with uninfested walnuts. due to genetic imbalance between parents. Specified Source(s) of Funding: Federal competitive Federal Program Name, Award Number: National Science Foundation under Grant No. 2:30–2:45 pm DEB-0423704, Central Arizona - Phoenix Long-Term Ecological Effect of ReTain on ‘Serr’ Walnut Yields in California Research (CAP LTER). Kathy Kelley Anderson* University of California Modesto CA; [email protected] Robert Beede Oral Session 13: University of California Hanford CA; [email protected] Nut Crops/Genetics/Physiology Joseph Grant University of California Stockton CA; [email protected] Tuesday, 22 July 2:00–3:35 pm Salon 9 Moderator: Michele Warmund, [email protected] Janine Hasey University of California Yuba City CA; [email protected] 2:00–2:15 pm Pistillate flower abortion is the main factor limiting yield in ‘Serr’ A Sensory Lexicon for Black Walnut (Juglans nigra L.) walnut. An excess of pollen grains on pistillate flowers causes auto- catalytic ethylene production, leading to embryo abortion and flower and Persian Walnut (J. regia L.) abscission. The active ingredient in ReTain, aminoethoxyvinylglycine Michele Warmund* HCL (AVG) is a transient inhibitor of ethylene biosynthesis. Field University of Missouri Columbia MO; [email protected] trials have demonstrated economic yield increases with a single ground application applied at 30% pistillate bloom at the rate of 50 g Janelle Elmore AVG/379 liters of water/0.4 ha in seven of ten orchards evaluated in Elmore Consulting Columbia MO; [email protected] 2006. Results from aerial applications were less promising in 2007 A study was conducted to develop a sensory lexicon for black and with no yield increases in two of three field trials conducted. English walnuts, including attributes for aroma, flavor, and texture. For Specified Source(s) of Funding: Private (Association, Foundation, this study, fruits were harvested in Windsor, MO, from wild seedling Industry) Industry/Association Program Name, Award Number: Valent trees and grafted trees of five black walnut cultivars (Sparks 127, Spar- BioSciences Corporation (2006 only) row, Emma K, Kwik Krop, and Football) in Sept. 2006. Fruits were immediately hulled and nuts were dried at 21 °C for 5 weeks before kernel extraction. Shelled ‘Chandler’ and ‘Tulare’ English walnuts 2:45–3:00 pm were obtained from a commercial source in Esparto, CA. Eight panel members trained in the Spectrum method of descriptive analysis with Evaluation of Resistance to Pecan Scab in a Seedling previous experience in nut evaluation generated 22 terms with defini- Progeny of Pecan Using Detached Leaflets tions at the North Carolina State University Sensory Center. Black Patrick Conner* walnut kernels were distinguished from those of English walnuts by University of Georgia, Tifton; [email protected] their fruity, musty, and sweet flavors. ‘Jackson’ kernels rated lower in fruity and musty flavors than those of ‘Sparrow’, although most values In order to facilitate the breeding of scab resistant pecan [Carya il- for sensory attributes of black walnut cultivars were similar. ‘Tulare’ linoinensis (Wangenh.) C. Koch] cultivars, more information is needed and ‘Chandler’ kernels generally had higher ratings for woody, bitter, about the genetic control of resistance to the causal organism, Clado- and astringent flavors than those of black walnut samples. sporium caryigenum (Ell. et Lang.) Gottwald (1982). Field inoculations are difficult to carry out because of the effect of environmental Specified Source(s) of Funding: Department, College, State and/or variation on disease expression and infection with native strains of C. HATCH Private (Association, Foundation, Industry) caryigenum often obscures the results of controlled inoculations. This talk outlines the development of a detached leaflet protocol for the evaluation of resistance to C. caryigenum isolate De-Tif-3 in a seedling 2:15–2:30 pm population segregating for resistance. Leaflets at and full expansion The Impacts of Walnut Husk Fly (Rhagoletis completa were detached from seedling trees, sprayed with a conidial suspen- Cresson) Infestation on English Walnut (Juglans regia L.) sion, placed in a polyethylene bag in a growth chamber, and evaluated Quality microscopically 7 and 14 days after inoculation. The percentage of germinated conidia producing subcuticular hyphae was found to the William Coates* best determinate of susceptibility, with those genotypes producing University of California, Hollister; [email protected] more than 15% subcuticular hyphae considered susceptible. Leaflets at expansion had higher percentages of subcuticular hyphae and gave Walnut husk fly (WHF) is a serious pest of English walnut cultivars a clearer separation between susceptible and resistant genotypes. An in California. Maggots of WHF infest the hull and result in increased evaluation period of 14 d was preferable to 7 d to allow slower reacting shell staining, kernel darkening, shrivel and mold as well as difficulty in genotypes be better evaluated. The detached leaflet was evaluated in hull removal. There have been few quantitative measurements of WHF varying environments and was found to be fairly robust to variations impacts on walnut quality. Eight paired 1000-gram WHF-infested and in shading and leaflet wetness. Detached leaflet tests gave similar re- uninfested samples of walnuts were collected from five cultivars over sults to field inoculations, but were superior in consistently detecting a 4-year period. Overall, a 31% loss in relative value was observed susceptible genotypes. This protocol will be useful in evaluating the in WHF-infested walnuts. Significant increases in the percentages of inheritance of pecan leaf scab resistance in breeding progenies. adhering hull, mold and shrivel were noted in WHF-infested nuts. Significant decreases were measured in mean nut weight, percentage of Specified Source(s) of Funding: Department, College, State and/or edible yield, percentage of large sound nuts, percentage of extra-light HATCH colored kernels, and reflected light index in WHF-infested walnuts. WHF damage occurring later in the season resulted in no loss of the

1102 HORTSCIENCE, VOL. 43(4), JULY 2008 3:00–3:15 pm United States, elevation patterns were along a longitudinal gradient. Morphological and Photosynthetic Characteristics of Sun However, SD and SI did not follow a pattern along the latitude or the longitude in the U.S. populations. An unclear pattern for 13C discrimi- and Shade Pecan Leaves nation in Mexican and U.S. populations translated into the absence of Leonardo Lombardini* differences between populations for water use efficiency (WUE). Texas A&M University, College Station TX; [email protected] Specified Source(s) of Funding: Federal competitive USDA Germplasm Hermann Restrepo Diaz Committee: Pecans Texas A&M University, College Station TX; [email protected] Astrid Volder Texas A&M University, College Station TX; [email protected] Oral Session 14: Nursery and Ornamental Crops 1 An experiment was conducted to investigate the morphologic charac- Tuesday, 22 July 2:00–3:39 pm Salon 10 teristics and photosynthetic response of sun and shade leaves of mature pecan trees. Treatments were established according to leaf type (sun Moderator: Richard C. Beeson, Jr., rcbeeson@ufl.edu or shade leaves) and cultivar (Pawnee and Stuart). Sun leaves were chosen from those growing on exterior portions of the tree canopy 2:00–2:15 pm ORALS–TUESDAY -2 -1 and exposed to full sunlight for most of the day (>1500 µmol·m ·s Wireless Sensor Networks for Real-time Management of photosynthetic photon flux density, PPFD). Shade leaves were those growing in interior parts of the tree canopy (<100 µmol·m-2·s-1 PPFD). Irrigation and Nutrient Applications in the Greenhouse Photosynthetic light response curves and chlorophyll fluorescence and Nursery Industry analysis were performed on leaves present on branches (about 2 cm John D. Lea-Cox* in diameter) which were cut from the mid-portion of the canopy and University of Maryland College Park MD; [email protected] immediately placed in water. Epidermis characteristics, leaf area, and chlorophyll (chl) content were measured from additional leaves pres- Andrew G. Ristvey ent on the same cut branches. Results indicated that stomatal density University of Maryland Queenstown MD; [email protected] -2 (stomata·mm ), leaf area, and leaflet area were greater in sun than Felix R. Arguedas in shade leaves in both cultivars investigated. Specific leaf area (m-2 University of Maryland College Park MD; [email protected] leaf area·kg-1 DM) was greater in shade than sun leaves. Chlorophyll fluorescence, total chlorophyll content, chl a, chl b, and chl a/b were not David S. Ross affected by either leaf type or cultivar. In both cultivars, photosynthetic University of Maryland College Park MD; [email protected] light response curves showed that area based maximum assimilation rate (A ) in shade leaves was about half of that measured in sun leaves George A. Kantor max Carnegie Mellon University Pittsburgh PA; [email protected] in June-August. In October, however, Amax of sun leaves dropped to values similar to those measured in shade leaves. Light compensation We have developed, deployed and tested a low-cost multi-hop wire- point of photosynthesis and dark respiration rate were always lesser less sensor network that enables the capture and synthesis of real-time in shade leaves than in sun leaves. Overall there were only minor substrate and environmental data on a wide-area basis. Concern over differences between the cultivars. Pecan trees require careful canopy the intensive use of groundwater, deterioration of surface waters, and management to avoid overshadowing and maintain productivity. These various state and federal nutrient and water management regulations results could help determine optimal levels of canopy light interception are making us re-examine the efficiency of water and nutrient manage- and intensity of pruning or hedging techniques. ment strategies in the nursery and greenhouse industry. Plant water Specified Source(s) of Funding: Department, College, State and/or requirements vary by day, season, and microclimate, depending on HATCH any number of environmental and plant developmental factors; thus precision irrigation scheduling is extremely difficult. By using the plant to integrate these environmental and growth differences over time, and by accurately monitoring the real-time water use of plants with 3:15–3:30 pm substrate moisture, temperature, and electrical conductivity sensors, Variation in Anatomy and Carbon Isotope Discrimination irrigation and nutrient applications can be more precisely scheduled. in Leaves of Pecan Populations from Mexico and the This can reduce water use, leaching of nutrients, and overall runoff United States from these intensive growing operations. Additionally, other sensors that simultaneously measure air temperature, canopy relative humidity, Madhulika Sagaram* leaf wetness, and photosynthetically active radiation will allow us to University of Florida Lake Alfred FL; madhulika@ufl.edu model and better predict plant growth and disease pressure. We can now Leonardo Lombardini provide this data at any time to anyone at any place with internet access, Texas A&M University College Station TX; [email protected] since all data is managed through a web-based graphic-user interface. Since the sensor nodes are portable, growers can rapidly deploy them L.J. Grauke in specific areas of the operation, to maximize the utility and cost of U.S. Department of Agriculture Somerville TX; [email protected] the sensors. Also, as these networks are scaleable, additional nodes can be added, allowing for an operation to grow and/or improve their An assessment of leaf anatomical traits of [Carya illinoinensis (Wan- sensor network at any time. We will compare and contrast the cost genh.) C. Koch] Mexican and U.S. pecan populations grown in a single and utility of this research sensor network with a commercial wireless location was conducted to provide an understanding of patterns of sensor network that has been installed on a tree farm in Maryland, to ecogeographic variation within the natural range. For the Mexican improve water and nutrient management efficiency. populations, pecan stomatal density (SD) and stomatal index (SI) were more closely related to precipitation patterns of the origin site along a Specified Source(s) of Funding: Department, College, State and/or longitudinal gradient than elevation patterns along the latitudinal gradi- HATCH Private (Association, Foundation, Industry) Maryland Ag- ent. SD and SI in pecan populations increased along the longitudinal ricultural Experiment Station / Maryland Cooperative Extension / gradient towards the east coast of Mexico. Geographical areas with Chesapeake Bay Trust / Horticultural Research Institute greater precipitation on the east coast of Mexico had greater SD and SI while the drier areas on the west coast had the least values. In the

HORTSCIENCE, VOL. 43(4), JULY 2008 1103 2:15–2:30 pm tree production are discussed. Evaluation of an ETo-based Operational Irrigation Specified Source(s) of Funding: Department, College, State and/or Algorithm Using Two Genera of Container-grown Woody HATCH Private (Association, Foundation, Industry) MSU PROJECT Ornamentals GREEEN Industry/Association Program Name, Award Number: Michigan Christmas Tree Association Richard Beeson* University of Florida, Apopka; rcbeeson@ufl.edu Actual evapotranspiration and canopy dimensions were collected 2:45–3:00 pm from Ligustrum japonica and Viburnum odoratissimum plants dur- Tolerance of Three Flood-tolerant Nyssa Species to Water ing production of rooted cuttings to market size plants in 11-L black polyethylene containers. From these data, along with corresponding Deficit reference evapotranspiration (ETo), algorithms based on canopy Nickolee Boyer* closure and canopy size were derived for each species and the com- Iowa State University, Ames; [email protected] bined data. These algorithms were compared to a manually adjusted William Graves irrigation targeting 1.78 m of overhead irrigation annually. The basic algorithm required only tri-weekly manual inputs of average canopy Iowa State University, Ames; [email protected] width and container spacing. Applications rates and frequency of ir- Trees indigenous to soils that flood periodically have proven resilient rigation were controlled by a data logger and based on the previous in landscapes characterized by large fluctuations in soil moisture. day’s ETo and rainfall. For Ligustrum, the basic algorithm and one of Several members of the genus Nyssa L. occur in periodically flooded its simplifications produced >85% of the measured plants to market wetlands and can tolerate extended periods of flooding, but little is size with less irrigation than the control, and under the 1.78 m annual known about their capacity to tolerate water deficit. We investigated irrigation target. The algorithm developed from combined data from responses to water deficit of three Nyssa species found in nature in both genera was as successful for Viburnum as the algorithm derived different hydrologic conditions. Nyssa sylvatica Marsh. (black gum) solely from the Viburnum data. This attest to the strength of the algo- occurs at diverse sites that range from drained uplands to periodi- rithm and suggest the possibility of grouping species for automated cally flooded bottomlands. Nyssa aquatica L. (water tupelo) grows irrigation control. Explanation of the algorithm and species response in periodically flooded soils but also in continuously flooded swamps will be discussed. and lakes. In contrast, Nyssa ogeche Bartram ex Marsh. (Ogeechee Specified Source(s) of Funding: Department, College, State and/or tupelo) grows only in consistently wet soils, occurring primarily HATCH along rivers and permanently flooded swamps. These distributions suggest that N. aquatica and N. sylvatica possess tolerance to water deficit. We imposed water stress on potted seedlings by withholding water and irrigating when soil moisture decreased to below prescribed 2:30–2:45 pm percentages during an eight-week period. Root zones of control plants Plant Stress as Indicator for Irrigation Scheduling in were kept partially flooded. Both N. ogeche and N. aquatica reduced Fraser Fir Production leaf area and total above ground biomass during water deficit, but only N. aquatica increased root:shoot ratio. Root:shoot ratio was Pascal Nzokou* 0.66 for N. aquatica subjected to water deficit, a value similar to that Michigan State University, East Lansing; [email protected] for N. sylvatica under either soil moisture regime. Additionally, N. Nicholas Gooch aquatica plants closed stomata when subjected to water deficit but Michigan State University, East Lansing; [email protected] failed to reopen stomata fully when irrigated. These data suggest that N. aquatica possesses desiccation avoidance mechanisms not Bert Cregg found in N. ogeche that allow N. aquatica to tolerate long-term water Michigan State University, East Lansing; [email protected] deficit. Based on these findings, potential roles of N. aquatica in the Fraser fir (Abies fraseri) is currently the most valuable Christmas tree landscape will be discussed. species in Michigan and is now one of the major planted tree species Specified Source(s) of Funding: Department, College, State and/or in the State. However, the native range of Fraser fir in the Mountains HATCH Private (Association, Foundation, Industry) Iowa Nursery of Western North Carolina, Eastern Tennessee, and West Virginia re- and Landscape Association ceives more total precipitation and has lower average temperatures than Michigan. Consequently growing Fraser fir in Michigan presents some management challenges, including the need to provide supplemental 3:00–3:15 pm irrigation to meet the physiological needs of the tree. Several Michigan growers now routinely provide supplemental irrigation to maintain the Short-term Drought Tolerance of Container-grown quality of their trees. Recent water use regulation requires irrigators to Ornamental Plants in Response to Abscisic Acid (ABA) develop and document a clear rationale for irrigation scheduling. This Craig A. Campbell study investigates the use of plant water stress indicators for irrigation Valent BioSciences Corp Ocoee FL; [email protected] scheduling and timing for A. fraseri production. Canopy temperatures were continuously recorded by infrared thermometry (IRT). The IRT Joseph Conner readings were stored in a CR1000 datalogger (Campbell Scientific Cie, NC State University, Fletcher; [email protected] Logan, Utah). Weather parameters including air temperature, relative Anthony LeBude* humidity sensor, wind speed and direction, solar radiation, and rainfall were also continuously recorded and datalogged. Pertinent variables NC State University, Fletcher; [email protected] recorded between 13:00 and 14:00 each day were fed into models Reduced irrigation frequency often limits the duration of marketability derived from the Penman-Monteith equations to determined the crop for container plants in large retail outlets. During drought, plants pro- water stress index (CWSI), evaluated as tool for irrigation schedul- duce abscisic acid (ABA) to regulate water loss. Therefore, we tested ing in Fraser fir. Soil water potential was also continuously measured various concentrations of ABA on short-term drought tolerance of three with tensiometer and datalogged. The results showed that increases container-grown ornamentals. Hydrangea ‘Endless Summer’, gardenia in CWSI were correlated with increases in soil water potential data ‘August Beauty’, and Nandina ‘Gulfstream’ were watered thoroughly measured with tensiometer, indicating the need for irrigation. The 2-4 hr before treatment and grown under 35% shade cloth covered usefulness, practicality and limitations of such model in Christmas with white polyethylene. Plants were treated as a drench with 40 ml of

1104 HORTSCIENCE, VOL. 43(4), JULY 2008 solution per liter of container volume of either 0 (control), 125, 250, the total leaf areas for 2007. In conclusion, growth and physiological 500, or 1000 ppm ABA and not irrigated until they reached critical responses were species dependent. wilting point (CWP). CWP was assessed visually at 1000 HR daily by the presence of wilted foliage. Plants were designated unmarketable if Specified Source(s) of Funding: Department, College, State and/or CWP was reached. Applications of ABA in increasing concentrations HATCH Private (Association, Foundation, Industry) Project GREEEN increased the number of days to CWP for all species (~3-4 d more than Industry/Association Program Name, Award Number: MNLA MFPA the control), and therefore extended the days of marketability. Interior MDA foliage of gardenia became yellow one week after treatment, however this foliage dropped before plants reached CWP. After the experiment ended, all plants were re-watered and marketability was recorded the Oral Session 15: Culture & Management: Organic Crops following day at 1000 HR. For hydrangea, all plants treated with ABA returned to marketability, whereas the controls did not. For gardenia, Tuesday, 22 July 2:00–4:00 pm Salon 11 plants treated with 250 ppm or greater were marketable. For Nandina, Moderator: Manuel Palada, [email protected] plants did not regain marketability after watering. Although short-term drought tolerance was increased in this species, Nandina has the ability to tolerate drought stress well without exogenous ABA applications 2:00–2:15 pm (control was marketable for 23 days). The delayed signs of wilting on Organic No-till Tomato Production ORALS–TUESDAY the plant and its inability to recover after watering, however, may have masked the actual time Nandina can withstand drought in containers. Kathleen Delate* Possibilities for the use of ABA applications include irrigating container Iowa State University, Ames; [email protected] plants with this compound prior to shipping to large retail outlets. Andrea McKern Plants may maintain marketability longer as a result. Alternatively, Iowa State University, Ames; [email protected] plants could be allowed to dry before shipping, thus decreasing the weight associated with well-watered plants. Robert Burcham Iowa State University, Greenfield; [email protected] Specified Source(s) of Funding: Department, College, State and/or HATCH Private (Association, Foundation, Industry) Industry/Associa- The Rodale Institute initiated an Organic No-till Plus system in 2004, tion Program Name, Award Number: Valent Biosciences Corp. where commercial crops (corn, soybean, and pumpkin) were no-till drilled or planted into cover crops that were rolled with a roller/crimper. The roller, provided to Iowa State University, consists of a large steel 3:15–3:30 pm cylinder (10.5 ft wide × 16 in. diameter) filled with water to provide 2,000 lb. of weight. Cover crops were planted on Oct. 31, 2006, in Effect of Nutrition on Growth and Physiology of three treatments: 1) a control (no cover crop/tillage used after plant- Landscape Shade Trees in Pot-in-Pot Production ing); 2) a cover crop combination of winter wheat and Austrian winter Wendy Klooster* pea; and 3) a cover crop combination of rye and hairy vetch. Tomato Michigan State University, East Lansing; [email protected] seeds were planted in greenhouse trays on Apr. 23 and the cover crops were crushed with the roller/crimper on May 23, 2007. Eight-inch Bert Cregg ‘Roma’ tomato seedlings were transplanted in four replications of Michigan State University, East Lansing; [email protected] each treatment on June 4. Tomato plant height, weed populations, leaf R. Tom Fernandez and fruit number data were collected throughout the season. Tomatoes were harvested from Aug. 20 to Sept. 2, weighed and graded. Initial Michigan State University, East Lansing; [email protected] tomato plant height was greater in the rolled mulch compared to the Pascal Nzokou tilled treatment, but was equivalent among treatments on the last two Michigan State University, East Lansing; [email protected] sampling periods. There were no differences in leaf and flower number on three sampling periods. No disease developed in any treatment. Throughout much of the U.S., sales of container-produced deciduous Both cover crop treatments provided weed suppression, with the main shade trees are increasing relative to sales of balled and burlapped difference in weed suppression between the tilled and rolled cover crop (B&B). Pot-in-pot (PIP) production is a large factor in the overall treatments occurring early in the season, when weed management was container trend, especially in the upper Midwest where winter root most critical. There was a trend towards lower broadleaf weeds in the protection is essential. Although growth of plants in the PIP system has cover crop treatments compared to the control, particularly in the hairy been well-studied in the southern U.S., proper guidelines are lacking for vetch/rye treatment, but because of high weed variability, broadleaf northern climates. In this study, we examined growth and physiological weed differences among treatments were not significant on 4 out of response of deciduous shade trees grown in a PIP system in Michigan. 5 sampling periods. Grass weeds were lowest in the hairy vetch/rye In May 2006, we potted 1- 1 bare root liners of Acer × freemanii ‘ treatment at the end of the season. There was no significant difference Jeffersred’, A. rubrum ‘Franksred’, Liriodendron tulipifera, Platanus × in yield between cover crop and tilled treatments, averaging 56,840 acerifolia ‘Bloodgood’, Quercus rubra, Ulmus japonica × wilsoniana lb/acre. Tomato quality was high in all treatments, with the highest ‘Morton’, and U.’Morton Glossy’ (20 of each species) in 25-gal (100-L) rated tomatoes in the hairy vetch/rye treatment, and equal ratings in containers using 85% composted pine bark, 15% Canadian peat moss. the pea/wheat and tilled treatments. Treatments consisted of controlled-release fertilizer (Osmocote Plus 15-9-12) top-dressed at rates of 100, 200, 300, or 400 g per container Specified Source(s) of Funding: Department, College, State and/or for the 2006 growing season and 125, 250, 375 or 500 g per con- HATCH -Department, College, State and/or HATCH Federal competi- tainer for the 2007 growing season. We collected data regularly from tive Federal competitive USDA-NRCS May to October of both years. Growth continually increased through 400 g per container in 2006; increasing the rates by 25% in 2007 resulted in maximum growth at the medium level (375 g) and a decline 2:15–2:30 pm in growth rate at 500 g. Although growth did not increase beyond 375 Tomato Growth and Substrate Responses to Organic and g per container, both foliar nitrogen content and SPAD index continued to increase, suggesting luxury consumption occurred at the high Inorganic Fertilizer Sources rate. Photosynthetic response to treatment varied by species; most William B. Evans* species had lowest rates with 375 g or more of fertilizer. Species and Mississippi State University, Crystal Springs; [email protected] treatment had a significant impact on total leaf area for both seasons, however, pruning performed after the 2006 growing season reduced

HORTSCIENCE, VOL. 43(4), JULY 2008 1105 Guihong Bi of 60-90 kg N/ha varied among varieties, but were not significant. Mississippi State University, Crystal Springs; [email protected] Adoption of Organic Integrated Pest Management (OIpm) consisting of sex pheromones, sticky paper traps, bio-pesticides, such as Bacillus Several fertilizers made from organic materials and by-products are thuringiensis (Bt) and neem, significantly reduced leaf damage and being sold to horticultural markets in the United States. Growers can increased pod yields by 40% compared to untreated control plots. choose from compost-based products, which offer nutrient stabil- Damage by Lima bean pod borer was significantly lower in OIpm ity but relatively low nutrient concentrations, and non-composted plots than in untreated control plots, resulting in significantly higher fertilizers, which can have higher nutrient concentrations but also total and graded pod yield. Differences in the effectiveness of four less stability. As part of a series of greenhouse studies, we tested the bio-antagonist agents in controlling downy mildew, soybean rust, and response of young tomato plants to four rates of three fertilizers in anthracnose were not significant, but treatment with Trichoderma sp. 15-cm diameter pots. In addition to an unfertilized control, treatments significantly reduced root rot incidence and resulted in higher yields included: 14N-4.2P-11.6K controlled-release fertilizer (CRF) at 28, than other bio-agents and the control. Plastic mulch and frequent hand 56, 112, and 168 g/cu.ft.; a 4N-0.9P-1.7K enriched non-composted weeding were superior in controlling weeds. Vinegar spray (6% acetic broiler litter-based fertilizer (EBLF) at 1%, 2%, 4%, and 6% v:v; and acid) directed onto the weed leaves to avoid crop canopy damage and a balanced non-composted 3-1.3P-2.5K broiler litter-based fertilizer applied twice in the dry season with low subsequent weed emergence (BLF) at 1.34%, 2.67%, 5.34%, and 8.0% v:v. At 5 days after treat- significantly reduced ground cover of broadleaf weeds, but was less ment (DAT), substrate pH was significantly elevated in the EBLF and effective in controlling grasses and Cyperus species. Variety and farm- BLF treatments, compared to the control treatment. Treatment with ing system had significant effects on six nutritional qualities including EBLF or BLF had also increased substrate electrical conductivity isoflavones, sugar, dry matter, protein, oil, and pod color. over the control or the CRF treatments. At harvest, 38 DAT, growth index and shoot height were greater in all fertilized treatments than in Specified Source(s) of Funding: Private (Association, Foundation, the unfertilized control. Shoot dry weight increased with each incre- Industry) ment of CRF. For EBLF and BLF, the greatest dry weights were seen at intermediate rates. The higher rates of EBLF and BLF produced symptoms, including very dark green leaves, brittleness, and curved, 2:45–3:00 pm floppy, rank stems and petioles, which may have been associated with Summer Cover Crop and In-season Management System excessive nutrient concentrations. Affect Nitrogen Availability and Weed Density in Lettuce Specified Source(s) of Funding: Private (Association, Foundation, and Cantaloupe Industry) Department, College, State and/or HATCH USDA CRIS Projects MIS-212030 and MIS-149090 Industry/Association Pro- Guangyao Wang* gram Name, Award Number: In-kind support from Organic Growing University of Arizona, Maricopa; [email protected] Systems, Atlanta, GA. Milton McGiffen* University of California, Riverside; [email protected]

2:30–2:45 pm Mathieu Ngouajio Michigan State University, East Lansing; [email protected] Integration of Production Technologies for Organic Vegetable Soybean in Taiwan Chad Hutchinson University of Florida/IFAS, Hastings; cmhutch@ufl.edu Chin-hua Ma AVRDC–The World Vegetable Center Shanhua, Tainan, Taiwan; The effect of summer cover crop and management system on nitrogen [email protected] availability, weed growth, and yield in fall romaine lettuce (Lactuca sativa L.) and spring cantaloupe (Cucumis melo L.) were evaluated at Peter Juroszek Coachella Valley, California from 1999 to 2003. Cover crop treatments AVRDC–The World Vegetable Center Shanhua, Tainan, Taiwan; included cowpea [Vigna unguiculata (L.) Walp.] incorporated into the [email protected] soil in the fall (CPI), cowpea used as mulch in the fall (Cpm), sudan- Manuel Palada* grass [Sorghum bicolor (L.) Moench] incorporated into the soil in the AVRDC–The World Vegetable Center Shanhua, Tainan, Taiwan; fall (SGI), and a bare ground control (BG). The management system [email protected] treatments included conventional (CON), integrated crop management (ICM), and organic (ORG). The Cpm and SGI increased soil organic Ramasamy Srinivasan matter content and changed the soil nitrogen profile during both let- AVRDC–The World Vegetable Center Shanhua, Tainan, Taiwan; tuce and cantaloupe growth periods. Soil organic matter was higher [email protected] in the ORG system compared to the ICM and CON systems, but less Tien-chen Wang soil N was present during the lettuce growth period. Nitrate leaching was reduced under ORG management during lettuce and cantaloupe AVRDC–The World Vegetable Center Shanhua, Tainan, Taiwan; growth periods. The Cpm treatment had lower weed growth during the [email protected] lettuce growth period, but higher weed biomass during the cantaloupe Ray-yu Yang growth period in the first growing season compared to other cover crop AVRDC–The World Vegetable Center, Taiwan; [email protected] treatments. Weed growth was not affected by management system during lettuce growth. During the cantaloupe season, weed growth Increasing concern about environmental quality, human health, and safer in the ORG treatment was lower or equivalent in the first three years agricultural products has led to the development of organic vegetable but higher in the fourth year compared to the CON and ICM systems. soybean production technologies in Taiwan and other Southeast Asian Plants in the CPI treatment had the highest lettuce yield in the first countries. This study was initiated to: 1) integrate production technolo- two growing seasons, while the SGI treatment had the lowest yield in gies for organic vegetable soybean; 2) provide production guidelines the first growing season. However, SGI and CPI treatments increased for organic vegetable soybean farmers; and 3) extend improved pro- cantaloupe yield compared to the Cpm and BG treatments. The ORG duction technologies to other tropical countries. Improved cultivars, treatment had lower or equivalent lettuce yield in the first growing organic fertilization, integrated pest, disease and weed management, seasons and higher or equivalent yield in the last two growing seasons and nutritional qualities were evaluated. Cultivars TN-AV2 and KS9 compared to CON and ICM systems. Cantaloupe yields were reduced yielded higher than aromatic flavor variety Kaohime and KS6. Effects in the ORG management system by 15% and 18% compared to the of fertilizers and application methods on pod yield at an input level CON and ICM system, respectively.

1106 HORTSCIENCE, VOL. 43(4), JULY 2008 Specified Source(s) of Funding: Federal competitive Western Region Merritt Taylor Sustainable Agriculture Research and Education program Oklahoma State University, Lane; [email protected] Organic vegetable production relies on a variety of tactics for preventing losses to crop yield and quality, and reducing the associated production 3:00–3:15 pm cost increases, that result from weed interference. These tactics include Soil Nitrogen Responses to Increasing Crop Diversity and field selection, long-term field management, cultivation practices, Rotation in Organic Vegetable Production Systems mulching, and manual weeding, to name a few. The concept of using Danielle Treadwell* organic-approved herbicides for vegetable production is attractive in that it offers additional options where current practices are inadequate. University of Florida, Gainesville; ddtreadw@ufl.edu Preemergence and postemergence organic weed control products have Michael Alligood been researched. Corn gluten meal provides preemergence control of University of Florida, Gainesville; allybad@ufl.edu germinating seed. However, a better understanding of how to integrate it into production systems is needed. There is also a great need for Carlene Chase an effective burn-down postemergence herbicide for use in situations University of Florida, Gainesville; cachase@ufl.edu such as stale seedbed plantings. Ammonium salt of pelargonic acid has

Manish Bhan shown potential usefulness as a postemergence burndown herbicide ORALS–TUESDAY University of Florida, Gainesville; mbhan@ufl.edu for annual weeds. The planting of cereal rye cover crops is a practice that can have an impact on weed incidence in organic vegetable pro- Crop rotation, organic soil amendments, and cover crops are utilized in duction systems. However, there is a need for more information on organic farming systems to manage crop nutrients. A two-year experi- how to manage cover crops in order to maximize the weed control ment was initiated in 2006 at the University of Florida’s (UF-IFAS) benefits from this practice and thereby enable growers to receive the Plant Science Research and Education Unit in Citra, FL, on certified greatest possible return from expenses incurred by the planting of organic land (Arredondo fine sand) to determine the effect of sum- non-cash crops. Shallow incorporation of rye residues is found to be mer cover crops (CC) and crop rotation on soil nitrogen. Treatments a means of managing cover crops that provides measurable control of were: 1) high crop diversity (HIGH) [legume and grass CC bicultures annual weeds. This paper reviews research conducted in Oklahoma + vegetable crops (VC) with living mulches]; 2) intermediate crop on cover crop management for weed control, corn gluten meal as a diversity with legume CC (INT-L) + monoculture VC; 3) intermediate preemergence herbicide, and the use of pelargonic acid formulations crop diversity with grass CC (INT-G); and 4) a control of low crop as contact herbicides. diversity (LOW) (no CC + monoculture VC). All VC received UF- IFAS recommended fertilizer rates. Rotational effect was examined by Specified Source(s) of Funding: Department, College, State and/or using two different CC-VC rotations each calendar year: crops from HATCH rotation cycle 1 in 2006 received crops from rotation cycle 2 in 2007, and vice versa. Treatments were arranged in a RCB and replicated 4 times. Dry weights for INT-G sorghum sudangrass (Sorghum bicolor × 3:30–3:45 pm S. sudanense) and pearl millet (Pennisetum glaucum) ranged between Weed Community Changes during Transition to Organic 4067 to 5403 kg/ha and were similar to HIGH bicultures of sorghum Production sudangrass with velvet bean (Mucuna pruriens) and pearl millet with sunn hemp (Crotalaria juncea). Both years, INT-L velvet bean biomass John Masiunas* was low (715 and 118 kg/ha for 2006 and 2007, respectively) due to University of Illinois, Urbana; [email protected] poor stand establishment. CC total nitrogen (N) in sunn hemp in INT-L Isabel Rosa was higher compared to remaining CC treatments both years (95 and University of Illinois, Urbana; [email protected] 93 kg/ha in 2006 and 2007, respectively) but those differences were not - consistently observed in soil nitrate (NO3 ) content. Immediately prior Increases in weed populations during transition can discourage new to CC incorporation, soil nitrate to a 20-cm depth ranged from 3.9-4.0 organic farmers, reduce income, and increase seed banks. Our research mg/kg in 2006 and 4.3-5.5 mg/kg in 2007 with no differences among studied the emerged and seed bank weed populations during a four- treatments. Soil nitrate following fall VC harvest was similar among year transition to organic production. We evaluated three management all treatments in 2006, but variable in Fall 2007 likely due to rotation intensity systems combined with three soil improvement treatments, effects. Overall, CC have the potential to offset VC N requirements, as transition strategies. The high management intensity system had a but actual CC N contribution was limited by subtropical conditions vegetable crop rotation (tomatoes, cabbage and broccoli, and winter and inherent soil properties. squash). The medium management intensity system had an agronomic rotation (soybeans, wheat, and corn). In the low management intensity Specified Source(s) of Funding: Federal competitive USDA CSREES system we established a perennial ley (clovers, timothy, orchard grass, Integrated Organic Program (Award Number 00062309) and vetch) and managed it similar to CRP land. The soil improvement treatments were cover crops alone, cover crops and compost, and cover crops and manure. In 2003, the ley system had the most weeds in sub- 3:15–3:30 pm sequent years it had fewer weeds than other management intensities. Potential Components for Weed Management in Organic In the vegetable system, during the first year we used plastic mulch Vegetable Production Systems and straw to control weeds. The straw had seed, so volunteer wheat was a problem. In 2004 and 2005, the grain system had more weeds James Shrefler* than the vegetable system. The higher returns for vegetable produc- Oklahoma State University, Lane; jim.shrefl[email protected] tion allowed hand-weeding which likely reduced weed populations Charles Webber III compared to the agronomic system. The effect of soil amendment USDA-ARS-SCARL, Lane OK; [email protected] varied depending on year. In 2004, there were more weeds in the manure amendment and in 2005 there were more weeds in the cover Warren Roberts crop only amendment. Weed species composition changed depending Oklahoma State University, Lane; [email protected] on management intensity and year. Common lambsquarters became Lynn Brandenberger less frequent, mainly due to later plantings. Common purslane, a problem weed of vegetables, first was found in Brassica vegetables Oklahoma State University, Stillwater; [email protected] in 2005. Weed species diversity in the seed bank increased between 2003 and 2005. Species composition of the seed bank was similar to

HORTSCIENCE, VOL. 43(4), JULY 2008 1107 the composition of the emerged weed community with the exception potato yield by 26% to 40% in the Altiplano (Peru and Bolivia) covering that seeds from Amaranthus species were the most common. 63,000 ha of potatoes. Because of the threat of frost, 60% of this area is planted with bitter potatoes that are hardy to frost, but cannot be Specified Source(s) of Funding: Federal competitive USDA Integrated consumed fresh. Early work showed that several wild potato species Organic Program are hardy under normal growing conditions (non-acclimated freezing tolerance: NAFT). For example, S. acaule can survive temperatures as low as -5 °C. In addition, wild species, such as S. commersonii, are able 3:45–4:00 pm to increase its frost hardiness after a brief exposure to cold temperatures Managing Canada Thistle in Organic Cropping Systems (acclimation capacity: ACC). This species can acclimate in 7 days from Using Sudangrass -4 to -12 °C. We demonstrated that NAFT and ACC are independent components under separate genetic control. These results suggested Abram Bicksler that potato frost hardiness can only be improved through precise se- University of Illinois, Urbana; [email protected] lection for both of these components under controlled environments. John Masiunas* During the last 15 years, using somatic hybrids of S. tuberosum and S. University of Illinois, Urbana; [email protected] commersonii as well as sexual hybrids with S. acaule, we have made significant progress in moving frost hardiness to the cultivated type. Canada thistle (Cirsium arvense) is a vigorous, creeping perennial weed These studies utilized precise screening under controlled environment. that forms dense patches. There are few options to manage Canada Advanced breeding lines with improved frost hardiness (NAFT and thistle in organic cropping systems. Warm season annual cover crops ACC) as well as tuber yield comparable to cultivated parents have grow when Canada thistle root reserves and ability to regenerate are been identified. We are now in the process of utilizing these materials low and when seedlings first emerge. Competitive summer annual in breeding as well as testing these lines in the field. cover crops may prevent thistle growth, flowering and seedling establishment. The cover crop treatments were no cover crop (weedy Specified Source(s) of Funding: Private (Association, Foundation, fallow), buckwheat, Sudangrass, and Sudangrass + cowpea. The cover Industry) Supported by a University of Delaware Foundation grant crop treatments were mowed either none, one or two times. Cowpea and the Trentman Endowment could not compete with Sudangrass and most cover crop plants in the mix were Sudangrass. Even without treatment, the number of Canada thistle shoots decline over the growing season. This decline in number 4:15–4:30 pm of shoots in a patch of Canada thistle is natural and is likely due to Estimation of Optimal Sample Size for Detecting Tuber failed establishment, competition between thistle plants, and pest at- Internal Defects in Potato using a Bootstrap Method tack. Cover crops and mowing acted independently to reduce thistle patches. At 3 months after planting cover crops, thistle was 21% and Felix Navarro* 3% of initial numbers in the buckwheat and Sudangrass (alone or with University of Wisconsin–Madison Rhinelander WI; [email protected] cowpea), respectively. In the second year, the field was intensely tilled Jiwan Palta and we planted organic food-grade soybeans. In soybeans, the areas University of Wisconsin–Madison, Madison WI; [email protected] formerly with Sudangrass or Sudangrass + cowpea had Canada thistle populations approximately 2% of those the previous spring. Canada In most agricultural research projects, sample size to estimate a popu- thistle shoots emerging in these areas were stunted and not competitive lation parameter is determined either by empirical means drawn by with the soybeans. Mowing and buckwheat only suppressed thistle for previous experiences, by adapting methods used by other researchers a single growing season. Sudangrass rapidly grows, tilling extensively, or by a compromise given by the time or economic resources needed forms a tall dense canopy, tolerates mowing, quickly regrows, and to process a given sample number. Besides the practical considerations when mown, forms thick mulch. when choosing a sample size, this decision has important statistical consequences that determine the efficacy achieved using a sample Specified Source(s) of Funding: Department, College, State and/or size. It is understood that a direct relationship between sample size and HATCH sample to sample variability. In addition, sample to sample variability is directly related to detect statistical differences from a population when they truly exist. A bootstrap procedure using sample sizes from 15 to 180 tubers representing possible sample sizes used in potato breeding Oral Session 16: programs to estimate tuber internal defects. The smallest, optimum, Breeding, Genetics and Germplasm: Vegetable Crops 1 sample size that minimizes the sample variation was established for three hypothetical varieties with 3%, 6%, and 9% hollow heart was Tuesday, 22 July 2:00–3:45 pm Salon 8 established. Several sample sizes used in breeding program results on Moderator: Jiwan Palta, [email protected] high type I and type II error rate. The bootstrap procedure represents a powerful method to identify optimal sample size for the study of statistics such as the percentage of hollow heart in potatoes. 4:00–4:15 pm Specified Source(s) of Funding: Department, College, State and/or Improving Freezing Tolerance of Cultivated Potatoes: HATCH Private (Association, Foundation, Industry) Federal com- Moving Frost Hardy Genes from Wild Potatoes and petitive Making Real Progress using Precise Screening Tools Jiwan Palta* University of Wisconsin–Madison; [email protected] 4:30–4:45 pm John Bamberg Selection for Resistance to Common Scab in Wisconsin University of Wisconsin–Madison; [email protected] Potato Breeding Lines Sandra Vega Felix Navarro* University of Wisconsin–Madison; [email protected] University of Wisconsin–Madison, Rhinelander WI; [email protected] Bryan Bowen The common cultivated species Solanum tuberosum is frost sensitive and is killed at temperatures below -2.5 °C. It has been estimated that University of Wisconsin–Madison, Rhinelander WI; [email protected] by increasing frost hardiness by 1-2 °C one can expect an increase in

1108 HORTSCIENCE, VOL. 43(4), JULY 2008 Eugenia Banks 130 polymorphic markers between susceptible lines and PIs 114490, Ministry of Agriculture, Foods and Rural Affairs Guelph ON; eugenia. 128216, and 126932, respectively. Eight markers indicate areas of [email protected] potential introgression into Fla. 8233, twenty-five markers indicate areas of potential introgression into Fla. 8517, and six markers show Charlie Higgins possible introgressions into Fla. 8326. BSA was used to determine Heartland Farms, Hancock WI; [email protected] which of these introgressed regions are linked to resistance. Jiwan Palta Specified Source(s) of Funding: Department, College, State and/or University of Wisconsin–Madison; [email protected] HATCH Common Scab is an endemic disease of many potato fields in Wis- consin. Developing scab resistance is an important objective for the Univ. of Wisconsin potato breeding program. Varieties such as Atlantic 5:00–5:15 pm and Snowden share susceptibility to common scab which represents Evaluation of Oxalate Concentration in the U.S. Spinach potential losses in quality at harvest. Soil heterogeneity makes it Germplasm Collection difficult to select varieties with consistent resistance level. In 2006, a project was initiated to select breeding lines using three locations Beiquan Mou* with high common scab potential. In 2007, one hundred and sixty USDA-ARS, Salinas CA; [email protected] ORALS–TUESDAY breeding lines were evaluated in three locations: Alliston (Canada), In addition to its high nutrient content, spinach (Spinacia oleracea Hearland Farms, and Rhinelander in Wisconsin. All three locations L.) is also known to have greater amount of oxalic acid than most were effective in separating resistant from susceptible cultivars. A crops. Oxalic acid may form crystals with minerals to reduce the bio- mixed model was used to characterize resistance to common scab. availability and absorption of calcium and iron in diets, and calcium Seventy five lines were considered either susceptible or resistance due oxalate may deposit in the kidney of certain people as a common to their performance in at least two of the three locations. Seventeen form of kidney stone. Genetic improvement to reduce the amount of chipping lines had a performance similar to the observed between the oxalic acid must start from germplasm evaluation to identify sources resistant varieties ‘Superior’ and ‘Pike’. Similarly, eight russet lines of low oxalate content. The entire USDA spinach germplasm collec- performed with resistance level as ‘Goldrush’. The newly released tion (338 accessions) and 11 commercial cultivars were screened in russet varieties ‘Millennium Russet’, Freedom Russet’, and the elite a preliminary experiment with two replications. Putative accessions lines W1879-1rus and W2683-2rus were confirmed as scab resistant. with low oxalate levels that were identified, plus controls and com- Among the reds, ‘Red Pearl’ was the best performing variety and mercial cultivars, were included in another test with five replications W2609-1R and W7299-2R exhibited superior scab performance to confirm the results. There were significant differences in oxalate compared to ‘Dark Red Norland’. Using several locations in early concentration among the genotypes evaluated, ranging from 5.3 to evaluation provided the ability to select for scab resistance in Wisconsin 11.6% on a dry weight basis. The low-oxalate genotypes identified in breeding lines before they are promoted and transferred to growers our experiments are all Spinacia oleracea. None of the two Spinacia for on-farm evaluations. tetrandra and four Spinacia turkestanica accessions screened contained Specified Source(s) of Funding: Department, College, State and/or low levels of oxalate. Two accessions from Syria, PI 445782 (cultivar HATCH Private (Association, Foundation, Industry) Federal com- name Shami) and PI 445784 (cultivar name Baladi), consistently had petitive low oxalate concentration. When expressed on a fresh weight basis, oxalate concentration may be affected by the moisture content of the plant. Oxalate concentration had little correlation with types of 4:45–5:00 pm leaf surface and leaf weight per plant. With the genetic variation and sources of low oxalate concentration found, breeding of spinach for Inheritance of Resistance and Identification of Molecular a low level of oxalate seems feasible. Markers Linked to Bacterial Spot Race T4 in Tomato Specified Source(s) of Funding: Department, College, State and/or Sam Hutton* HATCH University of Florida, Wimauma; sfhutton@ufl.edu John W. Scott University of Florida, IFAS, Wimauma; jwsc@ufl.edu 5:30–5:45 pm Resistance to bacterial spot of tomato (Solanum lycopersicum), race Regional Specificity of Genetically Diverse Garlic T4 (Xanthomonas perforans) was characterized in three advanced Varieties breeding lines, Fla. 8326, Fla. 8233, and Fla. 8517, by generation Gayle Volk* means analysis (GMA). The GMA of Fla. 8326 (resistance derived USDA-ARS National Center for Genetic Resources Preservation, Ft. Col- from PI 126932) for two of three seasons (Fall 2006 and Summer lins CO; [email protected] 2007) indicated resistance is mostly dominant with significant additive and epistatic effects. The GMA of Fla. 8233 (resistance derived Carl Rosen from PI 114490) in Spring 2007 indicated resistance is controlled Department of Soil, Water and Climate, University of Minnesota, St. Paul; by additive, dominant and epistatic effects, with dominance being [email protected] the main contributor. Likewise, the GMA of Fla. 8517 (resistance Deborah Allan derived from PI 114490 and/or PI 128216) in Summer 2007 showed University of Minnesota, St. Paul ; [email protected] dominance to be the main effect in addition to additive and epistatic effects. Resistant and susceptible F2 plants were selected from each Angela O’Callaghan of the three populations to identify markers linked to resistance by a University of Nevada, Reno,Las Vegas; [email protected]

modified bulk segregant analysis (BSA). The F3 and F4 progeny of these selections were evaluated to confirm the resistance or susceptibility John Zandstra prior to including them in the BSA. The PCR-based markers, located University of Guelph, Ridgetown; [email protected] primarily near areas of the genome where resistance genes to various David Stern bacterial diseases have previously been identified, were screened for Garlic Seed Foundation, Rose NY; jcawley@fingerlakesorganic.com polymorphisms between the three PIs and susceptible breeding lines. Approximately 550 markers were screened to identify 90, 165, and Garlic is a profitable crop for small to medium-sized vegetable farmers. Despite the increasing market for specialty garlic, it is remarkable

HORTSCIENCE, VOL. 43(4), JULY 2008 1109 how little is known about the diverse types of garlic available. Farmers ‘Fuji’ and two irrigation systems for ‘Gala’ on four rootstocks on tree need to know which garlic types perform well under their growing growth, water use, fruit quality and mineral nutrients were studied. conditions, and they need reliable descriptors to publicize these types to All forms of drip systems used less water than full micro-sprinkler their customers. Bulbs from 10 diverse garlic types were sent to garlic (SP). Partial root drying sprinkler (PS) used 50% less water than SP. growers in 11 locations throughout the; and Canada. Bulbs harvested Trees with partial root drying drip and deficit drip received 65% of in 2006 were analyzed for physical and chemical characteristics and full drip. The amount of water used in July was higher than all other cloves were replanted in the growers’ fields for the 2007 season. The months. When trees were completely mature, each tree with SP system same traits were assayed after the second year. We found that some used about 6673 L while that with Full Drip (FD) used 4118 L per garlic types excelled in certain regions and that nutrient content and season, which was equivalent to 1010 mm and 624 mm, respectively. appearance was highly correlated with farming conditions. As a result Thus, FD resulted in as low as 38.3% and as high as 58.3% saving of this project, growers were introduced to new garlic varieties that in water over sprinkler system. ‘Fuji’ yield and quality, particularly performed well under their growth conditions, thus expanding their starch degradation pattern (SDP) and size were affected by irrigation potential markets. We also identified traits to aid in the classification treatments. ‘Fuji’ trees with water deficiency had lower leaf and fruit of garlic varieties. K. ‘Pacific Gala’ on B. 9 rootstock had more bourse shoots with fruit than those on other rootstocks. ‘Pacific Gala’ trees on B.9 ceased Specified Source(s) of Funding: Federal competitive This project its terminal growth and formed its terminal buds before the trees on was funded by the Northeast-Sustainable Agriculture Research and other rootstocks. ‘Pacific Gala’ fruits from trees on G.30 and B.9 had Education Program Grant number LNE05-231 and by the Garlic Seed higher SDP than those on RN-29 and Supporter 4, whereas trees on Foundation. RN-29 had higher fruit weight than those on B.9 and Supporter 4. ‘Pacific Gala’ on G.30 had more fruit cracks than those on any of the other rootstocks. ‘Pacific Gala’ on B.9 had higher leaf N, than those on Supporter 4 and G.30. Trees on B.9 had lower leaf K than those Oral Session 17: Fruit Crops 1—Culture and Management on other rootstocks. In contrast, trees on B.9 and RN-29 had higher Tuesday, 22 July 2:00–3:30 pm Salon 7 leaf Mg and trees on B.9 had higher leaf Ca than those on the other rootstocks. RN-29 and B.9 were found to be suitable for ‘Pacific Gala’ Moderator: Esmaeil “Essie” Fallahi, [email protected] in this experiment. Specified Source(s) of Funding: Department, College, State and/or 2:00–2:15 pm HATCH Pomology Program The Relationship Between Fruit Weight and Crop Load as Influenced by Three Apple Rootstocks at Multiple Locations 2:30–2:45 pm Richard Marini* Sunburn on Apples: Fifteen Years of Research in Chile Penn State University, University Park PA; [email protected] Supports Heat as the Main Cause of Damage As part of the NC-140 Apple Physiology Trial, ‘Golden Delicious’ trees Jose A. Yuri* on three rootstocks (M.9 T337, G.16, and M.26) were planted at 12 Centro de Pomaceas-Universidad de Talca Talca, Chile; [email protected] locations in 2003. In 2006, crop loads were adjusted by hand-thinning 2 Valeria Lepe to crop densities (CD) ranging from 2 to 12 fruit/cm of trunk cross- Centro de Pomaceas-Universidad de Talca Talca, Chile; [email protected] sectional area. At harvest, average fruit weight (FW) was estimated for the eight locations with an adequate crop. Analysis of covariance Alvaro Sepulveda indicated that there was a strong interaction between CD, rootstock, Centro de Pomaceas-Universidad de Talca Talca, Chile; and location. Therefore, the 24 slopes resulting from linear regression [email protected] of FW on CD were compared at the 5% level after adjusting for the Richard Bastias unequal variances due to location. Slopes varied from -12.0 to 2.3. CD had little effect on FW for G.16 at Ontario; the most negative slopes Facultad de Agronomia-Universidad de Concepcion Chillan. Chile; (>10.0) were estimated for M.26 at KY, M.9 in Mexico, and G.16 at [email protected] British Columbia. FW means, estimated for 3 levels of CD will be Claudia Moggia presented for each combination of location and rootstock. Implica- Universidad De Talca Talca, Chile; [email protected] tions for crop load management and management of future rootstock trials will be discussed. Jaime R. Gonzalez Centro de Pomaceas-Universidad de Talca Talca, Chile; [email protected] Specified Source(s) of Funding: Department, College, State and/or HATCH Private (Association, Foundation, Industry) IFTA Gustavo A. Lobos Centro de Pomaceas-Universidad de Talca Talca, Chile; [email protected] David Michael Glenn 2:15–2:30 pm USDA-ARS Kearneysville WV; [email protected] Water Use, Growth, Nutrients, Yield, and Fruit Quality Sunburn is the major problem affecting apple quality at Chilean com- of ‘Fuji’ and ‘Gala’ Apples mercial orchards. Several evaluations have shown that the damage Esmaeil Fallahi* can affect more that 40% of the fruit, depending on cultivar, plant age, University of Idaho, Parma; [email protected] season and geographic location. Since 1992, the Centro de Pomaceas from the Universidad de Talca (Chile) has conducted research in several Bahar Fallahi orchards, located between 34 8 and 35 7 S lat. The aim has been to University of Idaho, Parma; [email protected] determine the main factor inducing sunburn (temperature or UV radia- Bahman Shafii tion), as well as the physiological responses associated to the damage, University of Idaho, Moscow; bshafi[email protected] and the efficiency of different controls methods. Both laboratory and field studies indicate that temperature exerts a greater influence on the An increasing trend in water shortage and needs for high density orchards development of sunburn damage than UV radiation. Under labora- mandate the use of more efficient methods of irrigation and rootstocks. tory conditions, 42 °C for 5 hours were required to generate sunburn In this long-term experiment, effects of seven irrigation systems for symptoms, whereas in the orchard the same damage appears at about

1110 HORTSCIENCE, VOL. 43(4), JULY 2008 37 °C. From a physiological point of view, the epidermis of the exposed Deficit irrigation has been shown to increase water use efficiency side of the fruit to sun radiation had a higher amount of metabolites (WUE) of many agricultural crops. We evaluated partial rootzone such as phenols, anthocyanins, proteins and enzymes. Some of the drying (PRD) and regulated deficit irrigation (RDI) effects on growth, tested strategies of control were: sprays with solar chemical protectors leaf gas exchange, and root/shoot abscisic acid (ABA) signalling. (Surround™, Raynox™, Vitamin E, Sunshield™, and Vaporgard™), Seedlings of the citrus rootstock Swingle citrumelo were grown in evaporative cooling (over sprinkler irrigation), and shading nets. The Candler sand in a greenhouse. In the PRD study, root systems were chemical products proved to be less consistent on the control of sunburn split in half and allowed to establish in adjacent pots. There were than the shading nets, which were significantly effective in reducing the three treatments: Control (100% ET = 50% ET per half); PRD (50% disorder. Evaporative cooling was the most effective control method. ET applied to one half and no irrigation on the other); and 50% (25% Our results from damage induction experiments support the hypothesis ET applied to the both halves). PRD did not affect any growth or gas that heat would be the primary factor inducing sunburn, compared to exchange parameters, although ABA was higher in these plants than in UV radiation. In addition, trials using a pulse-amplitude-modulated those with both halves watered. Net CO2 assimilation rate and WUE fluorometer to measure cholorophyll performance indicated an in- were lower in the 50% treatment than in Control or PRD. Thus, PRD teraction of visible spectra radiation with temperature, increasing the and control plants behaved similarly, but a considerable amount of sensitivity of the tissue to sunburn damage. water was saved. Similar plants with intact root systems were used for the RDI experiments where three water regimes were applied: Specified Source(s) of Funding: Department, College, State and/or Control (100% ET), 75% ET and 50% ET. Although leaf gas exchange ORALS–TUESDAY HATCH was not affected, deficit irrigation decreased shoot growth more than root growth. 50% ET plants had higher ABA concentrations than the 2:45–3:00 pm Control and 75% ET. Thus, PRD treatments saved water without reducing growth whereas RDI limited growth. Requirements for Macro-and Micro-nutrients by High Density ‘Gala’ Apple Trees Specified Source(s) of Funding: Private (Association, Foundation, Indus- try) Industry/Association Program Name, Award Number: Amvac Lailiang Cheng* Cornell University Ithaca NY; [email protected] Richard Raba 3:15–3:30 pm Cornell University Ithaca NY; [email protected] Organic and Integrated Apple Production Systems for Six-year-old Gala/M.26 trees grown in sand culture (1.05 × 3.3 m) the Northeastern U.S.: Four Years of Research from the received a total of 30 g nitrogen per tree as 15 N-ammonium nitrate Ground Up in Hoagland’s solution via fertigation in a pre-determined optimal 2 Gregory Peck* regime. Cropload was adjusted to 8.2 fruit/cm trunk cross-sectional Cornell University Ithaca NY; [email protected] area at 10 mm king fruit by hand-thinning. At each of the seven key developmental stages throughout the annual growth cycle, four trees Ian Merwin were destructively harvested. Each tree was partitioned to spurs, shoots, Cornell University Ithaca NY; [email protected] spur leaves, shoot leaves, fruit, branches, central leader, shank, and roots for complete nutrient analysis. The average fruit yield was 18.8 We have completed a four-year (2004-07) comprehensive study of kg per tree with an average fruit size of 181 g. Both leaf and fruit the feasibility, profitability, agroecological and nutritional aspects nutrient status fell within the recommended optimal range. Therefore, of organic (OFP) and integrated fruit production (IFP) systems in the accumulation of nutrients represents the nutrient requirements by an established high-density orchard of disease resistant ‘Liberty’ these trees. The nutrient requirements for N, P, K, Ca, Mg, S, B, Zn, apple on M.9 rootstock, grown in upstate New York. Cumulative yields were similar in the two systems, ranging from 39.4 Mg·ha-1 to Cu, and Mn from budbreak to fruit harvest are 19.8 g, 3.3 g, 36.0 g, -1 -1 -1 14.2 g, 4.4 g, 1.6 g, 93.6 mg, 61.0 mg, 46.4 mg, and 185.0 mg per 62.5 Mg·ha in IFP system, and from 46.5 Mg·ha to 59.5 Mg·ha tree. The nutrient requirements by the new growth (fruit plus shoots in the OFP system. Fruit size was smaller in OFP than IFP during and leaves) account for all the requirements for N, P, K, Mg, S, and 2005, and OFP packouts were skewed toward smaller box-count cat- B by the whole tree and most of the requirements for other nutrients egories in 2005 and 2006. There were no differences in tree size or tree (Ca, Zn, Cu, and Mn) by the whole tree. Fruit has differential nutrient growth between the two systems. Leaf nutrient concentrations were requirements than shoots and leaves. In general, active shoot growth similar and adequate for most essential elements, although foliar Al and leaf area development from bloom to the end of shoot growth concentrations were ten-fold greater in OFP trees due to the repeated use of kaolin clay [Al Si O (OH) ] as a crop protectant. Fruit qual- have high requirements for all the nutrients, whereas the bulk nutri- 4 4 10 8 ent requirements by fruit occur from the end of shoot growth to fruit ity, as measured using both analytical and sensory evaluations, was harvest. At fruit harvest, fruit has more P, K, and B whereas shoots variable with no consistent treatment differences. Fruit antioxidant and leaves have more N, Ca, Mg, S, Zn, and Mn. activity and total polyphenolic content was similar between treatments. Organic fruit sustained more insect damage and cosmetic blemishes during most years. Variable costs of producing IFP fruit ranged 3:00–3:15 pm from $2062/ha to $2381/ha compared with $2512/ha to $3682/ha for OFP (18% to 69% greater in OFP). Using USDA size and color Effects of Partial Rootzone Drying and Regulated Deficit catagories and wholesale prices for ‘Empire’ apples, returns ranged Irrigation on Seedlings of the Citrus Rootstock Swingle from $10,480/ha to $26,409/ha for the IFP system in 2004-06, and Citrumelo $5,429/ha to $24,302/ha for the OFP system (averaging 8% to 48% Juan Carlos Melgar* higher in IFP); in 2007, the OFP system had greater returns due to Citrus Research and Education Center, University of Florida–IFAS Lake larger fruit size and a 35% price premium. Four years of evaluation Alfred FL; [email protected]fl.edu suggest that IFP is feasible in the Northeastern U.S., and that OFP is feasible for disease-resistant apples sold at a price premium to offset Jill Dunlop the added production costs. Citrus Research and Education Center, University of Florida–IFAS Lake Alfred FL; jdunlop@ufl.edu Specified Source(s) of Funding: Department, College, State and/or HATCH Private (Association, Foundation, Industry) Toward Sustain- James P. Syvertsen ability Foundation Citrus Research and Education Center, University of Florida–IFAS Lake Alfred FL; jmsn@ufl.edu

HORTSCIENCE, VOL. 43(4), JULY 2008 1111 3:30–3:45 pm C/h. Samples were removed at 3 °C increments, placed in a humid Performance and Economics of High Density Apple chamber at 18 °C for 4-5 d, and inspected for injury to cambium tissue and bud primordia. At the 8 Nov. sampling, ‘Heritage’ buds were the Planting Systems for the Processing Market least hardy in the tunnel and field, and ‘Nova’ buds were among the Terence Robinson* hardiest. Average bud hardiness across all varieties appeared greater NYSAES, Cornell University, Geneva NY; [email protected] in field than tunnel plants. When sampled on 18 Jan. (67 days after plastic was removed), buds of ‘Heritage’ and ‘Nova’ were the most Stephen Hoying hardy, and tunnel buds appeared as hardy as those from the field. On NYSAES, Cornell University, Highland NY; [email protected] average, cambium tissue in canes tolerated lower temperatures than Alison DeMarree buds. Additional tissues will be tested in later winter. These results Cornell Cooperative Extension, Newark NY; [email protected] indicate the buds of raspberry varieties acclimate to cold at different rates, and that acclimation may be delayed when canes are maintained A 5-acre field comparison of 4 orchard systems (Central Leader/M.7 in a moderated high tunnel environment during the fall. - 385 trees/ha, Vertical Axis/M.7 - 840 trees/ha, Vertical Axis/M.26 - 1196 trees/ha, and Vertical Axis/M.9 - 1656 trees/ha) with 7 culti- Specified Source(s) of Funding: Department, College, State and/or vars (NY674, Liberty, Fortune, Jonagold, Mutsu, Northern Spy, and HATCH Private (Association, Foundation, Industry) Fuji) was conducted on a commercial farm at Marion, New York, from 1994-2003. Cumulative yield in the first five years and over 10 years was positively related to tree planting density. Yields between 4:15–4:30 pm cultivars varied widely with NY674 yielding the most and ‘Northern Effects of Irrigation Method and Level of Water Spy’ yielding the least. Biennial bearing was high with ‘Northern Spy’, ‘Jonagold’, ‘Mutsu’, and ‘Fuji’ and lower with NY674, and Application on Fruit Size and Yield in Red Raspberry ‘Liberty’. Pruning requirements were highest for the Vertical Axis/M.7 during the First Year of Full Production followed by the Vertical Axis/M.9 while the Central Leader/M.7 and David R. Bryla* the Vertical Axis/M.26 were lowest. The first year establishment costs USDA ARS, Corvallis OR; [email protected] were linearly related to tree planting density. After planting, the low density Central Leader system continued to have a negative cash flow Diane Kaufman for 8 years whereas the high density Vertical Axis/M.9 system had Oregon State University, Aurora OR; [email protected] a negative cash flow for only 4 years. Thus, the total establishment Bernadine C. Strik costs over 6 years were similar across all planting densities. None of Oregon State University, Corvallis OR; [email protected] the systems had a positive net present value after 20 years but by 30 years the 2 highest density systems were positive. Profitability was A study was done to determine the effects of irrigation method and linearly related to tree density and depended strongly on fruit price, amount of water application on production and fruit quality in red yield, and initial tree price. The optimum planting density appears to raspberry (Rubus idaeus L.). Two cultivars, ‘Meeker’ and ‘Coho’, were be about 1600 trees/ha. This analysis revealed that new processing irrigated by overhead sprinkler or subsurface drip at 50%, 100%, and orchards in New York must have high early yield and mature yields 150% of the estimated crop evapotranspiration (ETc) requirement. of 60t/ha and a fruit price of $0.22/kg to be profitable. For established To adjust for differences in evaporation and application efficiency, processing orchards, the minimum profitable yield was 35 t/ha when approximately 75% more water was applied by sprinklers than by price was $0.22/kg. subsurface drip. All measurements were made in 2007 during the first year of full production (year 3). Total yields ranged from 11.0- 13.2 t/ha, depending on treatment, in ‘Meeker’, and 11.7-14.2 t/ha in ‘Coho’. Fruit quality was excellent with most of the crop suitable for Oral Session 18: IQF. Overall, yield was 13% higher in plants irrigated by subsurface drip than in those irrigated by sprinklers. Yield was also affected by Viticulture and Small Fruits/Culture and Management the level of water application, although only in plants irrigated by Tuesday, 22 July 4:00–6:00 pm Salon 11 subsurface drip. With subsurface drip, yield increased by 17% from 50% to 100% ETc and decreased by 6% from 100% to 150% ETc. Moderator: John M. Smagula, [email protected] Yield with sprinklers, in contrast, differed by only 4% among each level of irrigation. In general, plants irrigated by subsurface drip 4:00–4:15 pm produced larger fruit (‘Coho’ only) and more fruit per cane (‘Meeker’ and ‘Coho’) than those irrigated by sprinklers. Average fruit size in Cold Hardiness of Red Raspberry Cultivars Grown in ‘Coho’ was 4.3 g per berry with subsurface drip and 4.0 g per berry High Tunnels and the Field with sprinklers, while average size in ‘Meeker’ was 3.6-3.7 g per Michael Vonweihe* berry regardless of irrigation method. Fruit size was also influenced Michigan State University, East Lansing; [email protected] by irrigation level, with plants producing larger fruit when irrigated at 100 and 150% ETc than at 50% ETc. Lower yield and fruit size with Eric Hanson* sprinklers than subsurface drip was related to lower soil and plant soil Michigan State University, East Lansing; [email protected] water status due to a limited ability to use the sprinklers during harvest High tunnels are used for red raspberry production in many parts of (26 June to 24 July). Soil water content measured weekly during this the world in order to increase yields or berry quality, or alter harvest time averaged 21% to 28% when irrigated at 50% to 150% ETc by times. In areas that receive more snow than the structures can hold, subsurface drip but only 15% to 18% when irrigated at 50% to 150% plastic is removed during the winter. As a result, raspberry canes ETc by sprinklers. Consequently, by peak harvest, plant water potentials can potentially be injured by winter cold, particularly soon after the were -0.3 to -0.5 MPa lower in plants irrigated by sprinklers than in moderating affect of the tunnel plastic is removed. We compared the those irrigated by subsurface drip. hardiness of the raspberry (Rubus idaeus L.) cultivars Canby, Encore, Specified Source(s) of Funding: Federal competitive Northwest Center Heritage, and Nova grown inside a high tunnel and in the field. Canes for Small Fruits Research were sampled on 8 Nov. 2007 (just before plastic was removed) and 18 Jan. 2008 and subjected to controlled freezing. Canes were cut into two-node segments, wrapped in gauze and foil, and cooled at 3

1112 HORTSCIENCE, VOL. 43(4), JULY 2008 4:30–4:45 pm 5:00–5:15 pm Developing Blueberry Plants with Shock Virus Tolerance Enhancing Winter Forced Strawberry Productivity for the Pacific Northwest and Fruit Quality Through Light Manipulation in High Wei Qiang Yang* Tunnels Oregon State University Aurora OR; [email protected] Brian Ward* Robert Martin Clemson University, Charleston SC; [email protected] USDA-ARS Corvallis OR; [email protected] Robert Dufault Yongjian Chang Clemson University, Coastal Research and Education Center, Charleston North America Plants LLC Lafayette OR; offi[email protected] SC; [email protected] In the Pacific Northwest, Blueberry shock virus (BlShV) causes short ChromatiNets are colored greenhouse netting with special optical term blighting of flowers and young leaves in young and established properties which specifically modify the spectrum of incident solar blueberry fields, resulting in yield loss for one or two years. After radiation for crop enhancement. A field experiment was designed to test the initial shock phase plants recover and do not exhibit symptoms the effects of these nettings on high tunnel winter forced strawberries. again. The virus is pollen-borne and transmission is facilitated by In Summer 2007, a high tunnel (29 m × 4 m × 2.5 m) was solarized to ORALS–TUESDAY bees. Three highbush blueberry cultivars (‘Duke’, ‘Bluecrop’, and kill weed seed and pathogens. Canadian certified disease- and pest-free ‘Elliott’) that tested positive for BlShV by ELISA and RT-PCR were strawberry ‘Sweet Charlie’ daughter tips were greenhouse propagated selected for tissue culture propagation. Tissue-cultured shoots from on July 27 under intermittent misting for four weeks using common all three cultivars tested positive for BlShV by ELISA and RT-PCR, plug production technology. On Aug. 24, the strawberry plants were indicating that the BlShV was passed on during tissue culture. These moved from the greenhouse and artificially conditioned until Sept. experiments provided evidence that BlShV was maintained through 12 in a walk-in growth chamber to shift plants from vegetative to tissue culture. These plants will be rooted and planted in the field to reproductive state. The conditioning treatment exposed the plugs determine if the severe reaction observed after infection can be avoided to a 12-hr day/night cycle with a 24 °C day/12 °C night. Plots were by starting with plants preconditioned for BlShV tolerance. fertilized with 672 kg 10-10-10/ha and rototilled. Drip tubing was placed between each of the six rows and the beds were covered with Specified Source(s) of Funding: Private (Association, Foundation, reflective mulch. Three photoselective ChromatiNets , Red, Yellow, Industry) Oregon Agricultural Research Fundation Pearl, and a non-netted control were used to cover the high tunnel in 7.3-m wide swaths with a 1.5 m uncovered buffer between colors. Transplants were planted Sept. 12, 45 cm between and 30 cm within 4:45–5:00 pm rows with cultural management based on commercial spring production methods. Yields between Thanksgiving and Christmas showed The Evolution of Ohio Strawberry Plasticulture significantly more fruit and higher sugar content in the yellow and Production (2001-2007) white netted plots when compared to the control. A second flush was Brad Bergefurd* observed in January with much higher yields and lower sugar content The Ohio State University Piketon OH; [email protected] across all treatments with fruit yield and sugar content significantly higher in the red netting plots when compared to the control. Shawn Wright The Ohio State University Piketon OH; [email protected] Specified Source(s) of Funding: Department, College, State and/or HATCH USDA-CSREES (Hatch) Thomas Harker The Ohio State University Piketon OH; [email protected] Strawberry plasticulture has been researched under southern Ohio 5:15–5:30 pm conditions since 2001. Our goal was to determine if strawberry plas- Fruiting ‘Campbell Early’ Grapevine is More Tolerant ticulture would be a viable strawberry season extension technique to Water Stress than Non-fruiting Grapevine under the for Ohio growers. There were several potential benefits identified to growing strawberries in plastic covered raised beds over the traditional Waterlogged Condition matted row culture system such as an earlier harvest, cleaner fruit, Seok-Beom Kang* ease of picking, and higher yields. A two year on farm non-replicated National Horticultural Research Institute, Rural Development Administra- trial was set up by authors with two southern Ohio growers. Results of tion Suwon, South Korea; [email protected] these observation trials were mixed, with more questions being raised Han-Ik Jang than answered: What are the correct planting dates for our area? What types of row covers are needed for winter protection? What varieties National Horticultural Research Institute, Rural Development Administra- perform well under southern Ohio conditions? In Fall 2001, replicated tion Suwon, South Korea; [email protected] trials were established at the Ohio State University Piketon Research In-Bog Lee and Extension Center to study winter protection covering materials, National Horticultural Research Institute, Rural Development Administra- cultivar evaluations and dates of planting. This paper will share the tion Suwon, South Korea; [email protected] results of our seven years of replicated strawberry plasticulture research and the lessons we have learned. Our last seven-year average Sang-Ggyu Lee replicated trial results have shown an optimal planting window for National Horticultural Research Institute, Rural Development Administra- southern Ohio being Sept. 10-20, with Chandler variety being the most tion Suwon, South Korea; [email protected] consistent yield performer with yields as high as 23,799 kilograms per Doo-Khil Moon hectare. Trial results have also indicated that row covers are required Cheju National University Jeju, South Korea; [email protected] for winter protection of strawberry plants in Ohio with the heavier 1.5 ounce floating row covers showing the least winter plant damage Bong-Nam Chung and higher yields. National Horticultural Research Institute, Rural Development Administra- tion Suwon, South Korea; [email protected] Specified Source(s) of Funding: Department, College, State and/or HATCH OSU South Centers The fruiting response of two-year old ‘Campbell Early’ grapevine cultivar under waterlogged condition was determined in a greenhouse for 6 weeks. Treatments of the experiment consisted of non-waterlog-

HORTSCIENCE, VOL. 43(4), JULY 2008 1113 ging without fruiting, non-waterlogging with fruiting, waterlogging (DAP) (224, 336, or 448 kg/ha) were applied alone or in combina- without fruiting, and waterlogging with fruiting. During the experiment, tion to 1.5 × 15 m treatment plots on 24 May 2007 in a commercial irrigation in the non-waterlogging treatment was controlled at -40 kPa blueberry field. One treatment plot received no fertilizer and served of soil water tension, while water level in the waterlogging treatment as a control. A randomized complete-block design was used with was kept at above 10 cm from the soil surface. At 20 days after wa- six blocks. Analysis of ten 7.6-cm deep soil cores/plot taken in July terlogging, soil redox potential of waterlogged soil was decreased at 0 indicated that gypsum decreased soil pH and increased soil Ca and 30 mV but control maintained at 520 50 mV. It was observed that the S, compared to the control and DAP only plots. Soil P was raised by net CO2 assimilation and growth of fruiting two-year-old ‘Campbell DAP at the 336 and 448 kg/ha rates, compared to the control or the Early’ grapevines under non-waterlogged condition decreased more plots receiving only gypsum. Composite leaf samples from 50 stems/ than that of the grapevine without fruit, while those of the fruiting plot taken in July at the tip dieback stage of development indicated grapevine in the waterlogged condition increased more than that of that leaf N and P concentrations increased with increasing levels of the grapevine without fruit. At drained after 4 weeks of waterlogging, DAP. Gypsum alone raised leaf N and P concentrations, compared the grapevines with fruit recovered more quickly and showed much to the controls, and were equivalent to concentrations of N and P for more vigorous root activity than the grapevines without fruit. This the 336 lb DAP/ha rate. Combining gypsum with DAP resulted in experiment indicates that fruiting ‘Campbell Early’ grapevines are higher leaf concentrations of N and P than DAP alone. Leaf K was more tolerant to water stress under the waterlogged condition. also raised by gypsum. Specified Source(s) of Funding: Department, College, State and/or Specified Source(s) of Funding: Department, College, State and/or HATCH HATCH Private (Association, Foundation, Industry)

5:30–5:45 pm Oral Session 19: Quantity of Abscisic Acid Applied Affects Harvest Date, Herbs, Spices, Medicinal Plants & Health Properties But Not Pack-Out of Red Table Grapes Wednesday 23 July 8:00–9:00 am Salon 8 Matthew Fidelibus* University of California, Davis, Parlier CA; [email protected] Moderator: Hazel Wetzstein, [email protected] Kimberley Cathline 8:00–8:15 am University of California, Davis CA; [email protected] Rapid Method to Quantify Flavonoids in Grapefruit Table grapes are often grown in warm climate regions where high Using High Performance Liquid Chromatography temperatures inhibit anthocyanin accumulation in the berry skins, thus suppressing color development. Recently, we showed that cluster Kranthi Chebrolu* directed sprays of abscisic acid (ABA) enhanced the color of ‘Flame Vegetable and Fruit Improvement Center College Station TX; Seedless’, ‘Crimson Seedless’, and ‘Redglobe’ grapes, and now we [email protected] are working to establish the most reliable and economical commercial G.K. Jayaprakasha protocols for the use of ABA to improve the color of table grapes. To Vegetable & Fruit Improvement Center College Station TX; [email protected] that end, we treated ‘Crimson Seedless’ and ‘Redglobe’ grapevines with an airblast sprayer calibrated to deliver the equivalent of 0, 25, 50, John Jifon 100, or 200 gal per acre of solution containing 200 ppm ABA. Clusters Texas A&M University, Texas Agricultural Experiment Station, Weslaco from each plot were harvested after most of the fruits in a given plot TX; [email protected] had met minimum market requirements. Coloring of ‘Crimson Seed- less’ grapes was improved by application of >100 gal per acre ABA, Bhimanagouda Patil* but the percentage of packable yield was rather low (40% to 65%) and Texas A&M University, College Station TX; [email protected] did not differ according to treatment. The low pack out was related to More than 50 flavonoids are known to present in citrus. The biologi- a high incidence of berry shrivel throughout the vineyard. ‘Redglobe’ cal activity of flavonones has recently been demonstrated including grapes, which were not affected by berry shrivel, were more responsive anti-inflammatory, anticarcinogenic, and anti-allergic properties. to the treatments than ‘Crimson Seedless’. ‘Redglobe’ grapes treated Quantification of these compounds in a single run has been always with >100 gal per acre ABA were harvested about 24 days before the challenging. The current study was aimed at developing a rapid method non-treated plots, and vines treated with 50 gal per acre ABA were for identification and quantification of major citrus flavonoids using harvested 7 to 12 days earlier than the vines treated with <25 gal per reverse phase-HPLC technique. Erocitrin, rutin, narirutin, naringin, acre. Between 80% and 95% of the potentially marketable ‘Redglobe’ hesperidin neohesperidin, hesperitin, didymin, poncirin, quercetin, clusters were harvested, regardless of treatment, so the primary effect naringenin, and tangeritin were separated using solvent gradient system of ABA, in 2007, was to advance harvest date. of acetonitrile and 0.03% phosphoric acid on C₁₈ spheri- Specified Source(s) of Funding: Department, College, State and/or sorb column and detected at 280 nm. The new method developed is HATCH Private (Association, Foundation, Industry) California Table rapid, reproducible, and capable of separating 12 flavonoids within 20 Grape Commission, and California Competitive Grant Program for minutes. The method was reconfirmed by measuring narirutin, narigin, Research in Viticulture and Enology Industry/Association Program hesperidin, neo hesperidin, and poncirin using ‘Rio Red’ grapefruit. Name, Award Number: Valent BioSciences Corporation Specified Source(s) of Funding: Federal competitive USDA-CSREES # 2006-34402-17121 “Designing Foods for Health” through the Veg- etable & Fruit Improvement Center. 5:45–6:00 pm Gypsum Enhances Nutrient Uptake of Lowbush 8:15–8:30 am Blueberry Evaluation of Antioxidant Capacity and John Smagula* Antiinflammatory Effects of Some Culinary and University of Maine Orono ME; [email protected] Medicinal Herbs Gypsum (CaSO ) is an organic soil amendment that contributes soil S 4 Weiguang Yi* and lowers soil pH. Gypsum (4000 kg/ha) and diammonium phosphate University of Georgia Athens GA; [email protected]

1114 HORTSCIENCE, VOL. 43(4), JULY 2008 Hazel Wetzstein* of glucoside at 17th position reduced the antagonistic potential in all University of Georgia, Athens; [email protected] three bioassays. These results suggest that furan ring and 7th and 17th positions in limonin structure may be important for the antagonistic Herbs have been long valued for their culinary attributes as flavorings, activity against AI-2 mediated cell-cell signaling and biofilm forma- seasonings and scents. A number of species with medicinal properties tion in Escherichia coli O157:H7. has been long used in folk medicines for the treatment of a number of conditions. Growing numbers of studies have supported the potential Specified Source(s) of Funding: Federal competitive The present re- health benefits of herbs with plant extracts displaying antioxidant, search is supported by the FY07-Federal Initiative Designing Foods antiinflammatory, antibacterial, analgesic, and antitumor activities. for Health through the Vegetable & Fruit Improvement Center, Grant Yet, general systematic comparisons of biochemical and biological No. TAES 06-118409. activity are limited, as is information on the effects of crop culture conditions. In this study, total phenolic content, antioxidant capacity and antiinflammatory activity were evaluated in five culinary and 8:45–9:00 am medicinal herbs: thyme (Thymus vulgaris), sage (Salvia officinalis), Moringa oleifera Lam. (Horseradish Tree) Growth rosemary (Rosmarinus officinalis), peppermint (Mentha piperita), and Performance Under Three Temperature Regimes spearmint (Mentha spicata). Antioxidant capacity was determined with the Trolox-equivalent antioxidant capacity (TEAC) assay. Antiinflam- Elsa S. du Toit* matory activities were evaluated using cycloxygenase (Cox-1 and University of Pretoria Pretoria, South Africa [email protected] Cox-2) bioassays after freeze drying the methanolic extracts. Total Quintin Muhl phenolic and TEAC activity exhibited marked differences. Based University of Pretoria Pretoria, South Africa; [email protected] on dry weight, more than two times difference was observed among species in TEAC activities; while more than four times difference Petrus Johannes Robbertse was observed when the measurement was based on fresh weight. and University of Pretoria Pretoria, South Africa [email protected] will be discussed. Also studied were the effects of greenhouse- vs. As we approach an era of dwindling oil reserves and soaring oil prices, field-grown culture on bioactive ingredient content. mankind has to search for alternative fuel sources. One such alterna- Specified Source(s) of Funding: Department, College, State and/or tive fuel source is biodiesel, which is primarily synthesized from HATCH natural plant oils. Although numerous oil-yielding crops are currently being cultivated worldwide for biodiesel production, it is the search for a biodiesel crop able to tolerate the harsh African climate that is

8:30–8:45 am the challenge. A tree with great potential in this respect is Moringa ORALS–WEDNESDAY oleifera Lam., as this is an alleged fast growing, drought tolerant, high Modified Citrus Limonoids: Differential Inhibition of oil-yielding tree with numerous other advantages. However, prior to Bacterial Cell-Cell Signaling the establishment of commercial biodiesel plantations, all cultural Amit Vikram* aspects of this promising tree have to be researched, this is the basis of Vegetable and Fruit Improvement Center, College Station TX; the research conducted by the biodiesel focus group at the University [email protected] of Pretoria. All M. oleifera trees are cultivated under three different temperature regimes, namely 10-20 °C 2 °C, 15-25 °C 2 °C and 20- G.K. Jayaprakasha 30 °C 2 °C, simulating possible day/night temperature fluctuations. Texas A&M University, College Station TX; [email protected] Currently the performances of 294 seedlings as well as 264 mature Palmy R. Jesudhasan M. oleifera are being examined, with remarkable results to date. No previous research on the environmental factors responsible for flower Texas A&M University, College Station TX; [email protected] initiation and development in M. oleifera has been done, however this is Suresh D. Pillai fundamental to enable commercial seed production. By gaining insight Texas A&M University, College Station College Station TX; into the factors affecting growth, flowering, and seed development, [email protected] possible geographical locations suitable for M. oleifera cultivation can be identified. Although high temperature favors tree growth, it seems Bhimanagouda S. Patil to inhibit flower development, while lower temperatures greatly reduce Texas A&M Univeristy-VFIC, College Station TX; [email protected] tree growth, but promote flower development. Temperature is found Citrus limonoids are furan-containing compounds with potential hu- to be a highly significant role-player in the cultivation of M. oleifera, man health promoting –properties. Previously, citrus limonoids have as the slight difference of 5 °C between the 30/20 °C and 25/15 °C exhibited anti-carcinogenic, cholesterol lowering, anti-HIV and GST- treatments revealed an average reduction of 50% in growth as well inducing properties. In our current studies, limonoids were found to as considerable differences in leaf morphology. inhibit cell-to-cell signaling and biofilm formation in bacteria. This Specified Source(s) of Funding: Department, College, State and/or observation prompted us to investigate the structure-activity relation- HATCH Private (Association, Foundation, Industry) ship of limonoids against autoinducer-1 (AI-1), autoinducer-2 (AI-2) mediated cell-to-cell signaling and biofilm formation in Escherichia coli O157:H7. Limonin was modified to obtain limonin-7-methox- ime, limonin-7-oxime and D-furan limonin. Limonin glucoside is Oral Session 20: Computer Applications: a natural glucoside of limonin with glucose moiety attached at 17th Horticulture, Teaching and Extension position. AI-1 and AI-2 mediated cell-to-cell signaling was studied using Vibrio harveyi-based bioluminescence reporter assay while Wednesday 23 July 8:00–9:00 am Salon 7 biofilm formation was investigated in Escherichia coli O157:H7. The Moderator: Lelia Kelly, [email protected] results showed a reduction in potency of all the four limonin-derived compounds against cell-to-cell signaling. Furthermore, removal of furan ring in D-furan limonin did not show any reduction in AI-2 8:00–8:15 am mediated bioluminescence activity, suggesting that furan ring might Development, Implementation and Evaluation of a Five- be important for AI-2 mediated cell-cell signaling. However, removal of furan ring did not affected biofilm formation. Moreover, methox- week Interactive Video Short Course on Roses ylation of limonoids at 7th position enhanced the potency to reduce Lelia Kelly* the production of Escherichia coli O157:H7 biofilm, while attachment Mississippi State University Verona MS; [email protected]

HORTSCIENCE, VOL. 43(4), JULY 2008 1115 Many consumers have viewed growing roses successfully in South- introduced to MSU plant scientists and given opportunity to stay con- ern gardens as a challenge due to disease control problems and other nected via the on-line Wonder Wall. Using this technology, students high maintenance tasks associated with rose culture. A member of the can ask questions, draw pictures or upload images of their plants. American Rose Society (ARS) contacted the Mississippi Extension Scientists serve as Wonder Wall moderators who answer student’s Service with the idea of collaborating to develop a short course that questions and encourage their ongoing discovery. This presentation would provide basic rose information and could be used as a prototype will report on who asks questions, how many questions are asked, by the ARS to encourage other states to develop their own state-specific what types of questions students ask and how long they stay connected rose short courses. The main objective was to encourage Mississip- to scientists. Initial data suggesting longer term impacts on interest pians to grow more roses by providing quality information on rose in science will also be discussed. Finally, find out how you can start selections, culture, maintenance, and other topics. Technical subjects a similar program including incorporating Wonder Wall technology including soil fertility, pruning techniques, rose disease and insect into your outreach programs. management, and propagation were offered along with less technical topics, such as rose crafts, roses in foods, and floral design, to appeal Specified Source(s) of Funding: Private (Association, Foundation, to a wide audience. The classes were offered in 2-hour sessions one Industry) Hebert H. and Grace A. Dow Foundation night a week for 5 weeks. All classes were taught by interactive video. Master Gardeners were targeted as participants as well as volunteers to assist in promoting the short course and to act as site facilitators for 8:45–9:00 am the interactive classrooms. Forty-two interactive video classroom sites Using INTERCOM Simulation Model to Compare throughout the state participated in this short course. Approximately Competitive Ability of Cowpea Genotypes with Different 500 people participated. Evaluations indicated the short course was beneficial, informative, and resulted in participants indicating they Growth Habits felt more confident and would purchase more roses to grow in their Guangyao Wang* home gardens. Complete evaluation summaries will be provided in University of Arizona, Maricopa; [email protected] the poster presentation. Milton McGiffen* Specified Source(s) of Funding: Private (Association, Foundation, In- University of California, Riverside; [email protected] dustry) Industry/Association Program Name, Award Number: American Rose Society Gulf District American Plant Food Dunlap and Kyle Ecophysiological simulation models provide a quantitative method to predict the effects of plant characteristics on crop and weed growth and competition. The INTERCOM interplant competition model was constructed to compare the competitive ability of cowpea (Vigna 8:15–8:30 am unguiculata) genotypes that differed in growth habit with common Illustration and Digital Snapshot Assignments Enhance sunflower (Helianthus annuus) and common purslane (Portulaca Learning from Online Lectures oleracea). The simulation results were compared with observations from field competition experiments in 2003 and 2004. INTERCOM Thomas Michaels* more accurately simulated field measurements for the competition of University of Minnesota, St. Paul; [email protected] cowpea genotypes and sunflower than field data for the competition An undergraduate plant propagation course was designed with lecture of cowpea and purslane. The validated simulation model of cowpea content presented on-line via WebVista and laboratories presented in a and sunflower at two densities was used to study the effects of cowpea traditional, face-to-face mode. To promote timely and effective learning growth habit on final biomass production of cowpea and sunflower. from the on-line lectures, students were assigned weekly illustrations The model suggested that erect growth habit was more competitive and digital snapshots of subjects closely related to each week’s lecture than semi-erect and prostrate growth habit when cowpea genotypes content. Students, in an end-of-course survey, overwhelmingly agreed were grown with sunflower, which was consistent with greenhouse that the act of drawing helped them to learn plant form and function replacement series and field measurements. Cowpea leaf area distri- and reinforced their understanding of lecture content. They also agreed bution was important to higher cowpea biomass production while that the digital snapshot assignments effectively assisted learning and cowpea height growth was important to reduce sunflower biomass. helped them relate lecture concepts to the natural world. Most students Our simulation approach is suggested as a method for crop breeders enjoyed the illustration and snapshot assignments. Few agreed that to gauge the likely success of selection for competitive crops before preliminary instruction in drawing or digital photography would have undertaking expensive long-term breeding experiments. enhanced the effectiveness of the assignments. Specified Source(s) of Funding: Federal competitive Western Region Specified Source(s) of Funding: Department, College, State and/or Sustainable Agriculture Research and Education HATCH

Oral Session 21: Biotechnology 2 8:30–8:45 am Seeds of Science: Growing Tomorrow’s Scientists Wednesday 23 July 8:00–10:00 am Salon 12 Norman Lownds* Moderator: Chris Dardick, [email protected] Michigan State University, East Lansing; [email protected] 8:00–8:15 am Young people’s interest in science decreases markedly as kids reach upper elementary and middle school. Their reasons include that science Anther Culture in Selenicereus and Hylocereus Vine is not fun, science is boring and it doesn’t relate to their lives. This Cacti (Cactaceae): Breeding, Evolution and Genetic mindset must be changed. Making this change requires that young Relationships people have opportunities to see themselves as scientists, to engage in the joy of scientiﬁc discovery, and to interact with scientists. If Reinerio Benega Garcia* this interaction can be sustained over time, it can serve as a catalyst J. Blaustein Institutes for Desert Research, Ben-Gurion University of the for growing tomorrow’s scientists. The Seeds of Science Program Negev Beer-Sheva, Israel; [email protected] at the 4-H Children’s Gardens is an example of how this can work. Noemi Tel-Zur Here students become “collaborating scientists “ doing experiments J. Blaustein Institutes for Desert Research, Ben-Gurion University of the that are almost identical to experiments going on at MSU. They are Negev Beer-Sheva, Israel; [email protected]

1116 HORTSCIENCE, VOL. 43(4), JULY 2008 Haploid and double haploid (DH) lines are extremely valuable for basic to fruit color population. Association analysis was carried out using genetic research and for accelerating breeding programs. Anthers from General Linear Model, taking population structure into account (TAS- three vine cactus species, Selenicereus megalanthus (allotetraploid), SEL GLM-Q). The five markers explained 77% of the variation for Hylocereus polyrhizus and H. undatus (diploids) were collected at the male/female character. The two markers explained 25% of variation mid-uninucleate of microspore development and cultured in vitro on for parthenocarpy, and up to five markers explained 40-48% of the Picloram/BAP and TDZ-containing MS culture media. Microspore variation for fruit color, and fruit weight and size. The closely linked ontogenesis started three days after in vitro culture and pro-embryoids markers are expected to facilitate crop improvement by shortening were formed in all three species. Callus formation was greater in H. selection time and efficiency. UPGMA and PCA analysis did not polyrhizus anther culture as compared to S. megalanthus. However, group the genotypes based on their geographic origins. However, the best androgenic embryoid response was achieved in S. megalan- there was a weak separation of males and females. Implications for thus anthers on MS-culture media with- and without Picloram. The fig breeding are discussed. best androgenic response for H. polyrhizus was achieved using 0.45 M TDZ. Anthers of H. undatus required a pre-treatment of 4 °C for Specified Source(s) of Funding: Federal competitive The Scientific 24 hours in 0.3 M D-mannitol to achieve callus response. Embryoids and Technological Research Council of Turkey (TUBITAK), Project from S. megalanthus and H. polyrhizus transformed into plantlets after No:105 O 056 being transferred to MS culture media in light conditions but plant regeneration was not obtained from calluses. H. undatus remained a 8:30–8:45 am recalcitrant species in the media and culture conditions tested here. Rooted plants were acclimatized successfully in a growth room and Transfer of Canker Resistance from Kumquat to exhibited a normal phenotype. Flow-cytometry studies revealed the Susceptible Citrus via Somatic Cybridization existence of haploid plants in H. polyrhizus and allohaploid plants in S. Jude Grosser* megalanthus, which was strongly genotype and culture media-depen- University of Florida, Lake Alfred FL; jgrosser@ufl.edu dent. These results open new perspectives in the genetics and breeding of vine cactus species. The production of allohaploid plants from S. Marta Francis megalanthus will enable us to determine its putative diploid ancestors, University of Florida, Lake Alfred FL; mfrancis@ufl.edu information valuable toward the understanding of evolutionary and James Graham genetic relationships among vine cactus species. To the best of our knowledge this is the first time that haploid plants have been produced University of Florida, Lake Alfred FL; jhgraham@ufl.edu in Cactaceae via anther culture or another related technique. Cybrids are a type of asymmetric hybrid that contains the nucleus of Specified Source(s) of Funding: Department, College, State and/or one parent in combination with the mitochondrial (mt) and/or chlo- ORALS–WEDNESDAY HATCH Post-doctoral Fellowship roplast (cp) genome of a second parent. Diploid somatic cybrids are often a by-product of citrus protoplast fusion in experiments aimed at producing allotetraploid somatic hybrids. The model method for somatic hybridization of citrus is the fusion of embryogenic cell 8:15–8:30 am culture protoplasts with leaf protoplasts of a second parent. Citrus Association Mapping for Sex and Fruit Characteristics in leaf protoplasts alone are not capable of cell division and subsequent Ficus carica plant regeneration. Following protoplast fusion, all recovered somatic hybrids and diploid plants exhibiting the morphology of the leaf parent Nedim Mutlu* always contain the mt genome of the embryogenic culture parent (the University of Nebraska, Lincoln; [email protected] latter group being cybrids). We have previously attempted to exploit Hatice Ikten this cybridization phenomenon by transferring mt-coded CMS (cy- Bati Akdeniz Agricultural Research Institute Antalya toplasmic male sterility) from Satsuma into seedy citrus varieties in Turkey; [email protected] efforts to reduce seed numbers in fruit. Recently, it was learned that at least one of several kumquat genes implicated in resistance to Asiatic Osman Gulsen citrus canker (caused by Xanthomonas axonopodis pv. citri) is housed Erciyes University, Kayseri, Turkey; [email protected] in the mt genome. In the present study, a detached leaf canker assay was conducted to compare a diploid cybrid of rough lemon 8166 (a Hilmi Kocatas citrus rootstock) containing the mt genome of Meiwa kumquat, with Erbeyli Fig Research Institute, Erbeyli / AYDIN, Turkey; the canker susceptible wild type rough lemon 8166. Results showed [email protected] that the cybrid rough lemon 8166 exhibited a high level of resistance Uygun Aksoy to canker, very similar to the hypersensitive response of the highly Ege University Izmir, Turkey; [email protected] resistant kumquat; whereas the wild type rough lemon 8166 began to develop canker lesions after one week. These results suggest that it Turkey is within the center of diversity for fig (Ficus carica L.) which might be possible to transfer mt-coded canker resistance from kumquat is an economically important crop. Association analysis, also known to commercially important canker susceptible cultivars, especially as linkage disequilibrium (LD) mapping or association mapping is a grapefruits and sweet oranges. population-based survey used to identify trait-marker relationships based on LD. Genetic diversity is evaluated across natural populations to identify polymorphisms that correlate with phenotypic variation. 8:45–9:00 am Thus, the objectives of this study were; to identify molecular markers Maximizing Somatic Embryogenesis and Regeneration linked to desired characters (male/female tree, fruit color, parthenocarpic/non-parthenocarpic fruits, and early/late crop formation) in fig, from Immature Papaya Seeds and to identify genotypic variation existing in female and male fig Trang Le* collection. Plant material was obtained from the germplasm collec- University of Hawaii at Manoa, Honolulu; [email protected] tion at Erbeyli Fig Research Institute, Ayd1n, Turkey, and consisted Richard Manshardt* of 47 male and 49 female genotypes for male/female population, and 96 female genotypes for fruit color, size, parthenocarpy and early/late University of Hawaii at Manoa, Honolulu; [email protected] fruit formation population. Fig genotypes with contrasting phenotypes Papaya (Carica papaya L.) embryogenic callus, derived by culture of (similar to BSA-bulked segregant analysis) were screened with SRAP, immature zygotic embryos (90-110 days after pollination) on medium ISSR, SSR and RAPD molecular markers. A total of 307 markers was containing 2,4-D, has been a popular target tissue for genetic engineer- generated, 150 of which belong to male/female population and 157

HORTSCIENCE, VOL. 43(4), JULY 2008 1117 ing, because single transformed cells have the ability to regenerate are abundant in grape EST sequences and they are a powerful marker entire transgenic plants. Our project objectives required large numbers tool for grape genotyping and phylogenic analysis. of transgenic plants; consequently, our goal was to maximize embryo production and plant regeneration through three developmental stages: Specified Source(s) of Funding: Federal competitive induction, germination, and rooting. Factors evaluated for effect on embryo induction included gelling agent (agar vs. Gelrite™), sucrose concentration (4%, 6%, 8%), 2,4-D concentration (6, 8, 10 ppm), and 9:15–9:30 am papaya genotype (Kapoho and Line D). Embryo germination was com- Intraclonal Selection for Potato Improvement pared on plates containing maturation medium solidified with either Atef Nassar* agar or Gelrite and sealed with either Parafilm™ or Micropore™ tape. We also examined the effect of IBA treatments (one hour or one week McGill University, Ste Anne de Bellevue QC Canada; atef.nassar@mail. in 2 ppm IBA) on rooting, prior to culture in media containing either mcgill.ca 0% or 3% sucrose. Results showed that 1) embryo production was Yves Leclerc enhanced by growth on Gelrite, both quantity and quality of embryos McCain Foods Canada Ltd., Florenceville NB Canada; [email protected] benefited from growth on media with high sucrose concentration, and the lowest concentration of 2,4-D allowed quicker maturation of embryos; Danielle Donnelly* 2) Gelrite facilitated quick germination of embryos, but resulted in McGill University, Ste-Anne-de-Bellevue QC Canada; danielle. high percentage of abnormal shoots, while Micropore™ tape increased [email protected] the percentage of normal shoots; 3) IBA enhanced rooting regardless Jihad Abdulnour of the presence or absence of sucrose, and the best root quality was McGill University, Ste Anne De Bellevue QC Canada; jihad. obtained by one-hour IBA treatment. Our conclusions are that 1) the [email protected] most effective medium for embryo production is Gelrite containing 6 ppm 2,4-D and 8% sucrose, 2) use of Micropore™ tape contributed The goal of this study was to determine if yield and processing charac- importantly to normal embryo germination on both agar and Gelrite, teristics of potato (Solanum tuberosum L. cv. Russet Burbank) could be and 3) best rooting of leafy shoots was obtained by a one-hour dip in improved through intraclonal selection. Intraclones were regenerated IBA followed by culture in sucrose-free medium. in vitro via somatic embryogenesis. Explants were taken from various source tissues from both field-grown tubers and in vitro- produced Specified Source(s) of Funding: Federal competitive Federal Program microtubers. Regenerated plants were hardened-off in the greenhouse Name, Award Number: USDA T-STAR Award No. 2005-34135- and transferred to the field in a complete randomized design (CRD). 16069 In 2005, approx. 500 intraclones were grown in the field as individual plants. In 2006, more stringent pre-selection was practiced on somatic plantlets before greenhouse-hardening. Approx. 300 intraclones were 9:00–9:15 am grown in the field, each one represented by two plants. At the end of Identification and Development of Single Nucleotide each season, tubers were harvested from individual plants. The high- Polymorphism (SNP) Markers from Grape EST est-yielding intraclones were identified using total tuber number and weight, marketable tuber number, weight and appearance, and average Sequence weight per tuber. These were stored, and later evaluated for fry-process- Jiang Lu* ing quality based on specific gravity, percent reducing sugar content, Florida A&M University, Tallahassee FL; [email protected] and fry color. Data were analyzed with SAS using the following tests: Shapiro-Wilk for normality, Bartlett for homogeneity, ANOVA, and Fitz Bradley Tukey’s for means comparisons. Tuber source or explant tissue did Florida A&M University, Tallahassee FL; fi[email protected] not affect tuber yield, type, or processing features. This suggests that Hong Huang explants can be taken randomly from source tubers in the future. Most Florida A&M University, Tallahassee FL; [email protected] intraclones had similar yield to control plants, although a small incidence (3% to 6%) had superior processing characteristics and were retained Single Nucleotide Polymorphisms (SNPs) are point mutations that for further evaluation. Intraclonal selection appears to hold promise occur frequently in eukaryote genomes, in which one nucleotide is in potato improvement but the overall effort, including logistics and substituted for another at a particular locus. SNPs are the most common costs, is similar to conventional breeding programs. type of alleles found within and between varieties of a crop species. These polymorphisms could be used as genetic markers for genotyp- Specified Source(s) of Funding: Federal competitive Federal Program ing, variety identification, phylogenic tree construction, gene mapping Name, Award Number: NSERC Discovery Grant to Dr. Danielle J. etc. In this research, we are mining SNPs from the grape Expressed Donnelly Egyptian government scholarship to Mr. amK Nassar Sequenced Tags (ESTs) by comparing the homologous partial gene sequence between Vitis vinifera, a predominant grape species cultivated worldwide, and Vitis shuttleworthii, a grape species originated from 9:30–9:45 am the southeast United State. The latter is considered as one of the most Stone Fruit Stones: A Model System for Studying Lignin disease /pest resistant grape species and has been used for developing disease resistant grape varieties for the deep South. A Set of 9,831 Biosynthesis and Regulation EST sequences generated from Pierce’s Disease (PD) infected leave of Chris Dardick* V. vinifera ‘Cabernet Sauvignon’(retrieved from the NCBI database) USDA-ARS The Appalachian Fruit Research Station, Kearneysville WV; and 12,008 ESTS of V. shuttleworthii were used for the sequence [email protected] comparison and SNP marker development. Contigs were assembled Ann Callahan among the combined 21,839 ESTs, from which 1,614 SNP sites were identified. Among them, a set of 148 contigs with a total of 350 SNPs USDA-ARS The Appalachian Fruit Research Station, Kearneysville WV; were selected for further validation and SNP marker development. [email protected] Among then, twenty-four SNPs derived from nine contigs with putative Ralph Scorza disease-resistance were selected for genotyping and phylogenic analysis USDA-ARS-Appalachian Fruit Research Station, Kearneysville WV; of sixty grape cultivars/accessions belonging to at least fourteen grape [email protected] species. The phylogenic tree constructed on the basis of SNP variations matched extremely well with the known classification of these grape Remo Chiozzotto species and cultivars. Based on this research, we concluded that SNPs Universit degli studi di Milano, Milan, Italy; [email protected]

1118 HORTSCIENCE, VOL. 43(4), JULY 2008 John Ralph glongbing) into Florida has renewed interest in guava, since closely US Dairy Forage Research Center, USDA-ARS Madison WI; john. interplanting citrus and guava in Vietnam appears to greatly slow [email protected] progression of citrus greening. It is hypothesized that guava volatiles may repel the greening vector, Asian citrus psyllid (Diaphorina citri). Robert Schaffer SSR analysis was conducted on all readily-accessible U.S. guava ac- HortResearch Aukland 1025, New Zealand; RSchaffer@hortresearch. cessions, as well as material (‘Bom’ and ‘Xaly nghi’) from Vietnamese co.nz citrus/guava orchards. Accessions numbered 73 distinct sources. Nine To maintain a competitive edge while expanding markets and decreas- SSR primer pairs, identified by Risterucci, et al., were used. Thus ing production costs, U.S. growers must continue to improve fruit far, 14 accessions have not amplified well in PCR. Alleles per locus quality and satisfy consumer demands for novelty and convenience. ranged from 4 to 8, with an average of 6.2. Only 40 genotypes were The development of seedless varieties of fruit such as grape, citrus, identified, since several accessions were synonymous. Cluster analysis and watermelon has significantly increased their consumption. The using the neighbor-joining method revealed four distinct affinities. The economic potential of doing the same for stone fruits is staggering, genetic differentiation within and among the groups showed marked considering the marketing possibilities for pitless cherry, peach, differentiation (FST = 0.325) and inbreeding was slight (FIS = 0.154). plum, and apricot varieties coupled with decreased production costs The Vietnamese accessions were in the two most closely related of for canned and dried fruit. However, achieving this requires not only the four clusters. It was important to identify U.S. material closely elimination of the seed, but the stone as well; a hard woody carapace related to the Vietnamese accessions, since they will be quarantined for surrounding the embryo. In pursuit of this goal, we have begun dis- two years and research on delaying greening is an immediate priority. secting the stone development and hardening process to identify key Some commercial guavas in Florida (?White Indonesian Seedless? regulatory genes and pathways. Gene expression profiling experiments and a group called ‘Thai White’ guava) are in the same clusters as the were conducted on an early peach fruit development series spanning Vietnamese cultivars. Even more closely-related material is available the stone hardening process. Two long-oligo microarray platforms within the U.S. The presence of the Vietnamese cultivars in two clus- were used for this study: A 5K custom peach fruit array and a 15K ters suggests that the properties of interest may be broadly distributed apple array from HortResearch, NZ. Results revealed that the phen- among cultivated guavas. It is also possible that the markers assessed ylpropanoid pathway that is responsible for lignin biosynthesis is do not correlate well with the trait of interest. highly induced immediately prior to stone hardening and then rapidly Specified Source(s) of Funding: Department, College, State and/or declines. Induction of this pathway was found to be stone specific as HATCH Federal competitive Federal Program Name, Award Number: significant induction was not observed in fruit flesh or skin. In contrast, USDA TSTAR program the flavonoid biosynthesis pathway was also found to be up-regulated during early fruit development, although the spatial/temporal pattern ORALS–WEDNESDAY was not tightly linked to stone hardening. Compositional analyses revealed that peach stones have unusually high lignin content (44%) Oral Session 22: Crop Physiology - Fruit Crops far above that observed in hard woods (25%), although the ratio of lignin monomers was consistent but not identical that of peach wood. Wednesday 23 July 8:00–10:00 am Salon 11 Collectively, our data provides a first look into the stone formation Moderator: Rongcai Yuan, [email protected] process and reveals numerous targets for engineering stoneless traits in Prunus species. 8:00–8:15 am Specified Source(s) of Funding: Federal competitive Federal Program Name, Award Number: National Science Foundation under Grant No. Effects of NAA and AVG on Young Fruit Abscission and DEB-0423704, Central Arizona - Phoenix Long-Term Ecological Expression of Genes Related to Ethylene Biosynthesis Research (CAP LTER). and Cell Wall Degradation in ‘Delicious’ Apples Hong Zhu* Virginia Polytechnic Institute and State University Winchester VA; 9:45–10:00 am [email protected] Guava SSR Analysis: Diversity Assessment and Eric Beers Similarity to Accessions Associated with Reducing Citrus Virginia Polytechnic Institute and State University Blacksburg VA; Greening in Vietnam [email protected] Ed Stover* Rongcai Yuan* USDA-ARS-USHRL, Fort Pierce FL; [email protected] Virginia Polytechnic Institute and State University Winchester VA; Tim Gottwald [email protected] USDA-ARS-USHRL, Fort Pierce FL; [email protected] The effects of NAA and AVG on young fruit abscission, fruit ethylene David Hall production, and expression of genes related to ethylene biosynthesis USDA-ARS-USHRL, Fort Pierce FL; [email protected] and cell wall degradation were examined in ‘Delicious’ apples. Naph- thaleneacetic acid (NAA) at 15 mg·L-1 enhanced ‘Delicious’ apple Malli Aradhya fruit abscission when applied at the 11 mm stage of fruit develop- USDA-ARS, Davis CA; [email protected] ment, while aminoethoxyvinyglycine (AVG), an inhibitor of ethylene -1 Francis Zee biosynthesis, at 125 mg·L reduced NAA-enhanced fruit abscission. AVG also reduced NAA-enhanced leaf and fruit ethylene production. USDA-ARS, Pacific Basin Agricultural Research Center, Hilo HI; francis. NAA-enhanced expression of ACC synthase genes MdACS5 A & B, [email protected] and ACC oxidase gene MdACO1 in fruit cortex and fruit abscission Jonathan Crane zones was decreased by AVG. However, AVG and NAA had no ef- Univ. of Fla., IFAS, TREC Homestead FL; jhcr@ufl.edu fect on the expression of MdACS1 in fruit cortex and fruit abscission zones. NAA only increased the expression of polygalacturonase gene The guava (Psidium guajava) is an evergreen tree in the Myrtaceae, MdPG2 in fruit abscission zones but not in fruit cortex. AVG reduced native to tropical America. It is grown throughout the tropics and NAA-enhanced expression of MdPG2 in fruit abscission zones. The subtropics of the world, and is used as a fresh fruit and processed into expression of -1,4-glucanase gene MdEG1 in fruit abscission zones juice, jelly, and paste. Recent introduction of citrus greening (huan- was decreased by NAA but was not affected by AVG. Our results

HORTSCIENCE, VOL. 43(4), JULY 2008 1119 suggest that ethylene biosynthesis and MdPG2 gene are involved in to fruit ratio (L:F) of selected FS was moderately (2005 and 2006) or young fruit abscission caused by NAA. strongly (extreme enforcing 2006) altered to either encourage or discourage movement of carbon from 13C-labeled sending FS to receiving Specified Source(s) of Funding: Department, College, State and/or FS, both located on the same main scaffold of V-shaped peach trees HATCH Private (Association, Foundation, Industry) at a distance of about 10 cm. At stage I and III of fruit growth, fruit and shoot tips were sampled from sending FS and receiving FS for determination of 13C percentage on the same day of labeling and after 8:15–8:30 am 1 week. In all three experiments and both growth stages, most of the Organ Loss and Yield impacts in ‘Valencia’ 13C was found in fruits and shoot tips of sending FS and no evidence of 13 Orange Due to Various Abscission Agent C enrichment was found in receiving FS. At stage III of ‘Redhaven’ peach fruit growth (2005), some 13C was also detected in fruits of Biweekly Applications Over a Two-year receiving FS only in the Encourage treatment and on the same day of Cropping Period in Florida labeling. In the extreme enforcing experiment, when all sinks were Jacqueline K Burns* removed only from sending FS, a small but detectable amount of 13C Citrus Res & Ed Ctr, Lake Alfred FL; [email protected]fl.edu was also recovered only in fruits of receiving FS at both growth stages, indicating that carbon movement across adjacent FS is possible and Luis Pozo* detectable by 13C tracing. The results obtained in this study indicate a University of Florida, Lake Alfred FL; lpozo@ufl.edu Main Author relatively high degree of peach branch autonomy even at the FS level. In order to adapt abscission agent application for ‘Valencia’ orange However, conditions of strong imbalance between source supply and mechanical harvest throughout the harvest season, unwanted flower, sink demand, either experimentally imposed or during periods of fruitlet and leaf drop must be eliminated. Ethephon (400 mg·L-1), 1- strong vegetative and reproductive sink competition, may cause some MCP (5 mM), ethephon + 1-MCP, CMNP (200 mg·L-1 and a water movement of carbon across neighboring fruiting shoots. control were applied to branches biweekly for two cropping years from Specified Source(s) of Funding: Department, College, State and/or full bloom in Mar. 2006 to Mar. 2008. All applications included 0.1% HATCH Kinetic adjuvant. Fruit detachment force (FDF) and/or organ retention in immature and mature fruit, flowers, and leaves were recorded. Eth- ephon alone caused high flower and/or fruitlet abscission when applied 8:45–9:00 am between full bloom (FB) and 120 days after FB. Mature fruit on the tree during this period readily responded to ethephon application by NAA, 1-MCP and AVG Differentially Alter a marked reduction in FDF. Beginning in mid-June, developing fruit Fruit Abscission and Fruit Ripening by were no longer responsive to 400 mg·L-1 ethephon. By November, Differentially Affecting Expression of Genes Related to fruit were again responsive to ethephon, and FDF was reduced by Ethylene Biosynthesis, Perception, and 60% of the water control. Application of ethephon + 1-MCP greatly reduced flower and/or fruitlet loss during the first 120 days after FB, Cell Wall Degradation in ‘Delicious’ Apples but had no effect on the onset of mature fruit response in November. Jianguo Li Application of 1-MCP alone slightly increased flower and fruitlet Virginia Tech., Winchester VA,China; [email protected] retention during the first 120 days after FB when compared to the Rongcai Yuan* control. CMNP application did induce flower and/or fruitlet abscission when applied during and after FB, but organ loss was much less and Virginia Polytechnic Institute and State University, Winchester VA; the period of time these organs were sensitive to CMNP was shorter. [email protected] Presenter By October, mature fruit became sensitive to CMNP. Leaf abscission Expression of genes for ethylene biosynthesis, ethylene perception, and was highly induced by ethephon application, but repressed to control cell wall degradation in fruit and fruit abscission zones was examined levels when 1-MCP was added. CMNP did not cause leaf abscission. in relation to fruit abscission and fruit softening after treatment with Yield effect of these treatments was assessed through whole tree ap- naphthaleneacetic acid (NAA), aminoethoxyvinylglycine (AVG), 1- plications at FB and 25 days after FB. Yield was negatively impacted methylcyclopropane (1-MCP), or the combination of NAA and AVG in by ethephon application, but less when 1-MCP was combined with ‘Delicious’ apples (Malus × domestica). The AVG or 1-MCP reduced ethephon. Application of 1-MCP alone or CMNP did not alter yield fruit ethylene production, delayed fruit abscission, and fruit softening; when compared to the control. whereas NAA reduced fruit abscission, but enhanced fruit ethylene Specified Source(s) of Funding: Department, College, State and/or production and fruit softening. The combination of AVG and NAA HATCH University of Florida/IFAS Citrus Initiative Funds delayed NAA-enhanced fruit softening, and resulted in much lower fruit abscission than did either AVG or NAA alone, although there was no significant difference in fruit ethylene production among these treatments. AVG or 1-MCP suppressed expression of ACC synthase 8:30–8:45 am gene MdACS1, ACC oxidase gene MdACO1, ethylene receptor gene Transport and Partitioning of 13C-photoassimilate MdERS1 and polygalacturonase gene MdPG1 in fruit, while NAA between Peach Fruiting Shoots enhanced expression of these genes. Only expression of ACS5A, MdACS5B, MdACO1, MdPG2 and -1,4-glucanase gene MdEG1 in Riccardo Lo Bianco* fruit abscission zones was decreased by AVG and 1-MCP. However, University of Palermo, Italy; [email protected] NAA only reduced expression of MdPG2 and MdEG1 in fruit abscis- Giorgio Volpe sion zones. The combination of NAA and AVG had synergic effects University of Palermo, Italy; [email protected] in suppressing expression of MdPG2 and MdEG1 in fruit abscission zones. These data suggest that NAA, AVG and 1-MCP differentially Mark Rieger affect fruit abscission and fruit softening through differentially affecting University of Florida, Gainesville; mrieger@ufl.edu expression of different members of MdACS, MdPG and MdEG genes 13 in fruit abscission zones and fruit in ‘Delicious’ apples. We used a non-intrusive method ( CO2 feeding) and a manipula- tive approach to see whether fruiting shoots (FS) in peach trees are Specified Source(s) of Funding: Department, College, State and/or autonomous or may import carbon from neighboring shoots under HATCH Private (Association, Foundation, Industry) forced conditions, and whether the degree of autonomy is influenced by the source-sink relationship on the shoot. In three experiments, leaf

1120 HORTSCIENCE, VOL. 43(4), JULY 2008 9:00–9:15 am (1500 micromole per square meter per second) for 2 hours resulted Safe and Unsafe Applications of Plant Growth Regulators in a significant decrease in maximum quantum efficiency (Fv/Fm) of the shaded peel at each developmental stage, with the decrease on Fruit Trees being larger with fruit development. We conclude that the increased Abdelfattah Wally* sensitivity of the shaded peel to photooxidative damage upon sudden Hort. Research Institute Zayed, Giza, Egypt; [email protected] exposure to high PFD with fruit development is caused by the decease in the overall capacity of the shaded peel to utilize absorbed light The identification of exogenous plant growth regulators and endogenous via photochemical and thermal dissipation processes and to detoxify hormones in tree tissues, mode of their actions and the factors affected reactive oxygen species. on their effectiveness will be discussed. The safe and unsafe applications of different plant growth regulators {auxins, gibberellins (GA), Specified Source(s) of Funding: Department, College, State and/or cytokinins (BA), abscissic acid (ABA) and ethylene or its sources} HATCH OARDC Research Enhancement Competitive Grant Program and their important effects on seed germination, rooting, tree growth, Federal Program Name, Award Number: USDA Floriculture and fruit yield and quality at picking and after picking will be reviewed and Nursery Research Initiative discussed. In addition, the effect of sprayed fruits by some hormones on human health will be discussed, as well as the factors affecting safe use of exogenous hormones on fruit trees. 9:45–10:00 am Extrafloral Nectar: Implications for Spray Application Specified Source(s) of Funding: Industry/Association Program Name, Award Number: NONE Federal Program Name, Award Number: and Pesticide Performance NONE Martin J. Bukovac* Michigan State University, East Lansing; [email protected]

9:15–9:30 am Extrafloral nectaries are found on plants in a wide range of taxa. They occur on important horticultural crops of Malus, Prunus and Pyrus sp. CPPU Delays Thins Fruit and Delays Maturity of and others. Extrafloral nectaries are nectar secreting structures, not as- ‘Pioneer Mac’ Apples sociated with floral organs, located primarily on petioles, near the leaf Renae Moran* lamina, and on serra along the leaf margin. Their distribution and role University of Maine Monmouth ME; [email protected] have been studied extensively because of their mutual relationship with insects, particularly ants. The nectar is rich in sugars and amino acids -1 CPPU was applied at a rate of 6 mg· L with several adjuvants, which and is hydrophilic. In sweet cherry (Prunus avium), nectar produced ORALS–WEDNESDAY were Latron” at 0.05%, petroleum oil at 0.5%, or Erase”, a plant-based by nectaries flows onto the leaf blade via the depression on the petiole, -1 oil, at 0.5%. NAA was applied at a rate of 6 mg· L to separate trees midrib, and venial network, and then over the interveinal areas cover- in neighboring rows of the same orchard. All treatments were applied ing the hydrophobic, wax fine-structure with a smooth, hydrophilic one week past petal fall to ‘Pioneer Mac’/B.9 apple trees. Each treat- substance. Most of the nectar produced was deposited on the adaxial ment was replicated six times. CPPU treatments thinned to a crop leaf surface. Micro-droplets of water or spray solutions, labeled with 2 density of 5.6 to 7.0 fruit per cm trunk cross-sectional area (TCA) Nigrosin dye as a marker, remained as discrete droplets on nectar-free compared to unthinned trees, which had a crop density of 12.4 fruit upper and lower leaf surfaces (contact angles about 68 degrees), but 2 2 per cm TCA, and NAA, which had 8.3 fruit per cm TCA. There was spread rapidly on the nectar completely wetting the surface (0 contact no difference in crop density or crop load between any of the CPPU angle). Typical wetting characteristics of a non-nectar surface were treatments. Although crop load was lower, the starch breakdown was observed after removal of the nectar. There was no evidence of modi- delayed and internal ethylene was lower in CPPU treatments compared fication of the wax fine-structure by the nectar. The presence of nectar to unthinned and NAA-thinned treatments. CPPU increased fruit reduced spray retention per unit area of leaf surface. Redistribution of firmness by approximately 4 N at harvest, after 2 months regular air Uvitex (fluorescent dye) was limited on nectar at low RH (45%), but on storage and 4 months CA storage. transfer to high RH (90%) the marker diffused throughout the nectar Specified Source(s) of Funding: Private (Association, Foundation, area. Residues of ethephon spray micro-droplets (120 to 300 microm- Industry) eters diam.) were readily identified by SEM as discrete deposits in the non-nectar, but were not apparent in the nectar-rich areas. However, the presence of the ethephon residue was confirmed in the nectar by 9:30–9:45 am x-ray analysis. Addition of nectar, eluted from sweet cherry leaves, to distilled water decreased surface tension by 3% at 0.01%, and by The Shaded Peel of Apple Fruit Becomes More Sensitive 24% at 1.0% concentration. The significance of nectar-modification to High Light Damage as Fruit Develops of leaf surface fine-structure and polarity on wetting and distribution Pengmin Li of foliar-applied compounds will be discussed. Cornell University, Ithaca NY; [email protected] Specified Source(s) of Funding: Department, College, State and/or Lailiang Cheng* HATCH Federal competitive Federal Program Name, Award Number: Cornell University, Ithaca NY; [email protected] SCA 58-3607-1-118, Agricultural Research Service, USDA Developmental changes of photochemical and non-photochemical processes and the antioxidant system in the shaded peel of ‘Gala’ Oral Session 23: Floriculture 3 apple and its response to sudden exposure of high light were monitored to understand why the shaded peel of apple fruit becomes more Wednesday 23 July 8:00–10:00 am Salon 10 susceptible to photo-oxidative damage with fruit development upon Moderator: Connie Johnson, johnscn@ufl.edu sudden exposure to high light. As fruit developed, actual photochemical efficiency of photosystem II decreased, whereas non-photochemical 8:00–8:15 am quenching increased at any given photon flux density (PFD). However, photochemical quenching coefficient of the shaded peel decreased Limestone Particle Size and Residual Lime at any given PFD with fruit development. Although the glutathione Concentration Affect pH Buffering in Container pool and catalase activity increased, the ascorbate pool decreased, Substrates and the activity of the other antioxidant enzymes either decreased or Jinsheng Huang* remained at a very low level as fruit developed. Exposure to high light University of Florida, Gainesville; huangj@ufl.edu

HORTSCIENCE, VOL. 43(4), JULY 2008 1121 Paul Fisher* of N without leaching. According to pm, 59.7 meq of acidity was ap- University of Florida, Gainesville; pfisher@ufl.edu plied by the fertilizer per liter of substrate. During the experiment, the pH of the substrate decreased from 7.05 to 4.41 for HL substrate and William Easton Horner from 7.14 to 5.13 for the CHL substrate. This drop in substrate-pH University of Florida, Gainesville; hornerwe@ufl.edu corresponded to 37.4 (HL) or 42.9 (CHL) meq of acidity per liter of William Argo substrate, applied in a laboratory titration of the same substrates with Blackmore Co., Belleville MI; [email protected] 0.5 N HCl (without plants). Gasometric analysis and NaOH titration of substrate alkalinity at the start and end of the experiment quantified Unreacted residual limestone plays a key role in buffering pH change neutralization in alkalinity over time, and averaged 30.7 and 30.6 meq/L over time in container substrates. We evaluated the substrate-pH ef- of substrate from the two methods, respectively. Acidity applications fect of (a) mineral acid drenches without plants, and (b) ammonium quantified using three experimental methods were 16.7 to 29.1 meq/L (acidic) or nitrate (basic) fertilizer applications with ‘Super Elfin’ lower than those expected from pm, suggesting pm overestimated the Impatiens wallerana (Hook. f.). Container substrates included ten amount of acidity applied to the substrate. commercial substrates and nine research substrates, which varied in residual calcium carbonate equivalents (CCE) from 0.3 to 4.9 g·L-1 Specified Source(s) of Funding: Private (Association, Foundation, In- CCE of substrate. Nine research substrates contained 70% peat:30% dustry) Young Plant Research Center, American Floral Endowment perlite (by volume) with dolomitic hydrated lime at 2.1 kg·m-3, along with one of four particle size fractions [850 to 2000 m (10 to 20 U.S. mesh), 250 to 850 m (20 to 60 US mesh), 150 to 250 m (60 to 100 US 8:30–8:45 am mesh), or 75 to 150 m (100 to 200 mesh)] of a dolomitic limestone -3 Temperature and Daily Light Integral Influence at 0, 1.5 or 3.0 kg·m . Increasing residual CCE in commercial sub- Flowering of Cosmos sulphureus ‘Cosmic Orange’ and strates were correlated with greater pH buffering in greenhouse plant experiments using a 100% ammonium-N acid-reaction fertilizer, and Verbena hybrida ‘Obsession Lilac’ when substrates were drenched with HCl without plants. Research Matthew Blanchard* substrates with high applied lime rate (3.0 kg·m-3) had greater pH Michigan State University, East Lansing; [email protected] buffering than at 0 or 1.5 kg·m-3. At 3 kg·m-3, the limestone particle size fractions of 250 to 850 m and 150 to 250 (20 to 60 or 60 to 100 Erik Runkle U.S. mesh) provided the greatest buffering in greenhouse experiments. Michigan State University, East Lansing; [email protected] Particle fractions finer than 150 m reacted quickly over time, whereas In the United States, annual bedding plant production is the largest buffering by particles coarser than 850 m was limited by slow reac- segment of the floriculture industry with a wholesale value of $1.7 tion rate during the 6-week experimental period. With basic fertilizer billion in 2006. The majority of these crops are produced in heated application, residual lime concentration did not affect pH buffering. greenhouses from January through May, when high energy inputs Addition of acid from acidic fertilizer or direct application of mineral are required in temperate climates. The increased cost of energy has acid reduced residual CCE over time. Dosage with 40 meq acid from necessitated the need for species-specific information on how tem- HCl per liter of substrate may provide a quick laboratory test to com- perature and photosynthetic daily light integral (DLI) influence plant pare pH buffering of substrates. Residual limestone is an important development so that the production environment can be optimized. substrate property which should be considered for pH management Seedlings of cosmos (Cosmos sulphureus Cav. ‘Cosmic Orange’) and in greenhouse crop production. verbena (Verbena hybrida Groenl. & R mpler ‘Obsession Lilac’) were grown in an environmental growth chamber at 20 °C with a mean Specified Source(s) of Funding: Private (Association, Foundation, -2 Industry) Department, College, State and/or HATCH DLI of 9.7 mol·m per day and under a 16-h photoperiod. Seedlings were transplanted into 10-cm pots and grown in glass-glazed greenhouses at constant air temperature set points of 14, 17, 20, 23, or 26 °C and under a 16-h photoperiod provided by high-pressure sodium 8:15–8:30 am (HPS) lamps. At each temperature, plants were grown under two Quantifying Fertilizer Acidity in a Peat-based Substrate DLIs, provided by the use of a shade curtain and different intensi- Connie N. Johnson* ties of supplemental lighting from HPS lamps. The experiment was -2 University of Florida, Gainesville; johnscn@ufl.edu performed twice and mean DLIs ranged from 4 to 19 mol·m per day. In cosmos, time to flower decreased from 72 to 34 d as mean daily Paul R. Fisher temperature (MDT) and DLI increased from 14 °C and 5 mol·m-2 per University of Florida, Gainesville; pfisher@ufl.edu day to 23 °C and 19 mol·m-2 per day. The greatest number of flower Jinsheng Huang buds at first open flower occurred on plants grown at an MDT of 17 to 20 °C and under 19 mol·m-2 per day. In verbena, time to flower University of Florida, Gainesville; huangj@ufl.edu decreased from 56 d at 14 °C under 5 mol·m-2 per day to 20 d at Richard P. Vetanovetz 23 °C under 19 mol·m-2 per day. Plants grown at an MDT of 17 °C and Sun Gro Horticulture, Marysville OH; [email protected] under 15 mol·m-2 per day were predicted to have the greatest flower bud number. These crop development models will be integrated into William R. Argo decision-support software to assist growers in predicting crop timing Blackmore Company, Belleville MI; [email protected] and the amount of energy used for heating during different times of Potential acidity of fertilizers can be estimated using Pierre’s method the year at various locations. (pm) in milliequivalents (meq) of calcium carbonate per 1000 kg Specified Source(s) of Funding: Private (Association, Foundation, of fertilizer. Pierre’s method was developed using mineral field soil Industry) MSU Project GREEEN (GR06-028) systems and may not apply to greenhouse culture. The pm-predicted acidity of an ammonium-based fertilizer was compared against experimental measurements with ‘Ringo’ Pelargonium × hortorum and 8:45–9:00 am ‘Super Elfin’ Impatiens wallerana grown in 70% peat:30% perlite (v:v) limed with either hydrated limestone (HL) or a mixture of carbon- Night Interruption and Cyclic Lighting Promote ate and hydrated limestone (CHL). Plants in 10-cm-diameter (0.35 L) Flowering of Long-Day Plants Under Low Temperature pots were irrigated with 2.0 L over 6 weeks using a 15N-1.7P-12.5K Jong Hwa Shin fertilizer (100% NH4-N) applied with every irrigation at 100 mg·L-1 Seoul National University Seoul, South Korea [email protected]

1122 HORTSCIENCE, VOL. 43(4), JULY 2008 Kyeong Joo Kang the latter period generally increased dry matter accumulation more Seoul National university Seoul, South Korea; [email protected] than that during earlier stages. Data will be presented on the relative value of increasing the DLI during different stages of bedding plant Wook Oh Seoul seedlings and the effects on subsequent flowering. National University Seoul, South Korea; fl[email protected] Specified Source(s) of Funding: Private (Association, Foundation, Ki Sun Kim* Industry) Greek State Scholarship Foundation Industry/Association Seoul National University Seoul, South Korea; [email protected] Presenter Program Name, Award Number: American Floral Endowment Heating costs could be considered as a problem in winter flower production. Night interruption (NI) is used as an alternative method to heating for promoting long-day plant flowering. To investigate NI ef- 9:15–9:30 am fects on flowering, long-day plants (Cyclamen persicum Mill., Eustoma Elevated Air Temperatures Cause Whitening of Ivy grandiflorum ‘El Paso Deep Blue’, Pelargonium hortorum ‘Pinto Red’, Geraniums Antirrhinum majus) were grown under three different temperatures (12 °C, 16 °C, and 20 °C), four NI lightings (0, 2, 4, 6 h), and two cyclic Ritu Dhir* lightings (CL) (6’/54’, 6’/24’ on/off) around midnight. Photoperiods Mississippi State University; [email protected] were 9/15 h day/night, and NI was provided by three-wave lamp with Richard L. Harkess* 3 1 µmol·m-2·s-1 during the middle of the dark period. Plants grown Mississippi State University; [email protected] at high temperature (20 °C) came to flower earlier than those at low temperature (12 °C and 16 °C). NI and CL lighting hastened flower The young developing leaves of ivy geranium (Pelargonium peltatum) initiation and flowering in each temperature regime. Plants grown at turn white, expand less, and develop an upward cupped appearance 16 °C with CL (6’/24’) lighting reached flowering 10 days earlier than when heat stressed. This physiological disorder is referred to as “whit- plants grown at 20 °C. Plant growth and the number of flower buds ening .” High temperatures and iron deficiency have been suspected and leaves at low temperature (12 °C and 16 °C) with NI lighting were as causes of whitening. This study was conducted to determine the similar to those of optimum temperature (20 °C) without NI lighting. effects of elevated air temperature and Fe-chelate on causing whiten- There were no significant differences in plant height and width at their ing in ivy geraniums. Rooted cuttings of ivy geranium, ‘Beach’ and treatments. These results indicated that NI and CL light treatments ‘Butterfly’ were potted on 15 Dec 2006 into 15 cm pots filled with could replace heating for plant flowering. Moreover, NI lighting ef- sphagnum peat and perlite (70:30 v/v). Plants were fertilized with fects on the other long-day plants such as Dianthus carthusianorum, 250 mg·l-1 of N (Peters Peat-lite 20N-4.4P-16.7K, Scotts Company, Viola wittrockiana Petunia hybrida ‘Matrix Scarlet’, ‘Mambo Red’, Marysville, Ohio) as a continuous liquid feed. Ivy geranium ‘Beach’ ORALS–WEDNESDAY and Primula malacoides ‘Libre Blue, Red’ will be discussed. and ‘Butterfly’ plants were grown in air temperatures averaging 35 C/18 °C (day/night) or 44 C/24 °C (day/night) on 2 Feb. 2007 for 6 Specified Source(s) of Funding: Department, College, State and/or weeks. Iron chelate was applied as a drench at 0 or 27 mg Fe (Sprint HATCH 138, Fe-EDDHA, 6% Fe, Becker Underwood Inc., Ames, Iowa) per pot at biweekly intervals. Plant height, width, growth index, foliar pigments, extent of whitening, plant biomass, and foliar Fe contents were 9:00–9:15 am measured. Elevated air temperature caused whitening of ivy geranium Daily Light Integral During the Seedling Stage Influences and reduced plant width, leaf area, and fresh and dry weight of both Transplant Quality and Subsequent Performance in cultivars. Growth index was reduced under heat stress for ‘Beach’, Selected Annual Plants but not ‘Butterfly’. Elevated temperatures reduced chlorophyll a and carotenoids concentration in ‘Butterfly’, but not in ‘Beach’ Fe-chelate Wook Oh* did not prevent whitening, but increased chlorophyll to carotenoids Michigan State University, East Lansing; [email protected] ratio (Chl : Caro) at elevated temperature in ‘Butterfly’. Fe-chelate Erik Runkle at 27mg and elevated air temperature resulted the maximum total Fe content in ‘Beach’. Temperature did not affect total Fe content in Michigan State University, East Lansing; [email protected] ‘Butterfly’. Ryan M. Warner Specified Source(s) of Funding: Department, College, State and/or Michigan State University, East Lansing; [email protected] HATCH Private (Association, Foundation, Industry) Industry/Associa- Increasing daily light integral (DLI) during the seedling stage tion Program Name, Award Number: Syngenta Flowers, Inc. promotes seedling growth and flowering in many bedding plants. Our objective was to determine the impact of increasing DLI for different periods of time during the seedling stage on young plant 9:30–9:45 am quality and subsequent plant growth and development. Seeds High Light Suppression of Phosphorus Uptake and of Tagetes patula ‘Bonanza Yellow’, Petunia hybrida ‘Madness Red’, Salvia splendens ‘Vista Red’, Pelargonium hortorum ‘Pinto Consequent Root Substrate Acidification by Geranium Red’, and Viola wittrockiana ‘Delta Premium Yellow’ were sown Matthew Taylor* into 288-cell plug trays and placed under a 16-h photoperiod North Carolina State University, Raleigh NC; [email protected] provided by sunlight plus 90 µmol·m-2·s-1 (high DLI, HL) or 3 µmol·m-2·s-1 (low DLI, LL) from high-pressure sodium lamps when the Jonathan Frantz ambient greenhouse PPF was <400 µmol·m-2·s-1 from 0600 to 2200 HR. USDA-ARS, Toledo OH; [email protected] The seedling stage was divided into thirds, and plants either remained Paul Nelson under LL or HL for the entire seedling stage, or were for exposed to HL North Carolina State University, Raleigh NC; [email protected] for one-third or two-thirds of the duration. At the end of seedling stage, plants were transplanted into 10-cm pots and grown until flowering Sudden pH decline (SPD) describes the situation where crops growing under HL at 20 °C. Mean DLIs during the seedling stage were about at an appropriate pH, rapidly (within 1-2 weeks) cause the substrate pH 8.1 and 11.9 mol·m-2·d-1 under the LL and HL treatments, respectively. to shift downward one to two units. ‘Designer Dark Red’ geraniums Seedling emergence of all species was hastened by about 1 d under (Pelargonium × hortorum Bailey) were grown in three experiments HL, which can at least partially be attributed to a 2.5 °C higher media to assess possible effects of light on SPD and P uptake. The first ex- temperature. In general, shoot growth, root growth, and leaf unfolding periment tested the effect of four light intensities (105, 210, 575, and increased with increased exposure to HL. Supplemental lighting during 1020 25 mol·m-2·s-1) on substrate acidification. At 63 d, substrate pH

HORTSCIENCE, VOL. 43(4), JULY 2008 1123 declined from 6.0 to 4.8 as light intensity increased. Tissue P of plants grown at the highest two light levels was low (0.10-0.14%). The P Oral Session 24: Water Utilization stress has been reported to cause acidification. Since plants in the two Wednesday 23 July 9:15–10:30 am Salon 8 lowest light treatments had adequate P, it was not possible to determine if the drop in substrate pH was a direct light effect or a combination Moderator: Seenivasan Natarajan, vasan@ufl.edu of light and P. The second experiment used a factorial combination of the three highest light levels from experiment one and five pre-plant P 9:15–9:30 am rates (0, 0.07, 0.13, 0.26, or 0.52 g·L-1 substrate) to assess this question. When tissue P concentrations were deficient, pH decreased by 0.6 to Effect of Arsenic Levels in Refill Water and Frond 1.0 pH units within two weeks and deficiency occurred more often Harvest Methods on Arsenic Phytoremediation by with high light. These data indicated that P deficiency caused substrate Chinese Brake Fern acidification and indicated the possibility that P uptake was suppressed Seenivasan Natarajan* by high light. The third experiment was conducted in hydroponics to University of Florida, Apopka; vasan@ufl.edu determine the direct effect of high light intensity on P uptake. The rate of P uptake per gram root per day decreased 20% when light intensity Robert Stamp* increased from 500 to 1100 mol·m-2·s-1. It is clear from this study that University of Florida, Apopka; rstamps@ufl.edu P deficiency causes geraniums to acidify the substrate and that high light suppresses P uptake. Uttam Saha University of Florida, Gainesville; sahau@ufl.edu Specified Source(s) of Funding: Department, College, State and/or HATCH Private (Association, Foundation, Industry) Lena Ma University of Florida, Gainesville; lqma@ufl.edu Yong Cai 9:45–10:00 am Florida International University, Miami FL; cai@fiu.edu Evaluating Ion and Water Uptake Edward Zillioux Patterns in Greenhouse Roses Environmental Bioindicators Foundation, Inc., Fort Pierce FL; Exposed to Mild Salinity Stress [email protected] Alma R. Solis-Perez A field-scale hydroponic system to phytoremediate arsenic (As) con- Texas A&M University, Dallas TX; [email protected] taminated groundwater using Pteris vittata (Chinese brake fern) was Raul I. Cabrera* tested successfully for the first time. In this study, a combination of two water refill sources [As-contaminated water (140-180 g·L-1)or clean Texas A&M University, Dallas TX; [email protected] water (low As, <7 g·L-1)] to replace evapotranspiration (ET) loss and Victor J. Florez-Roncancio three frond harvest methods (15-cm from rhizome, selective harvest Universidad Nacional de Colombia, Dallas TX; vjfl[email protected] of senescing fronds, and infrequent/no harvest) were investigated by repeatedly using the same plants in two separate cycles. Results indi- Greenhouse rose plants, ‘Happy Hour’budded on the rootstocks cate that using clean refill water was more effective (As was reduced Rosa manetti and R. × ‘Natal Briar’, where grown in recirculating from 140 to <10 g·L-1) in 8 weeks) compared to using As-contaminated hydroponic units having a base nutrient solution consisting of a 0.25X water (17 weeks) during Cycle-1. Re-use of same ferns in Cycle-2, Hoagland formulation that was supplemented with 4 mM NaCl. starting with 180 g·L-1) As, further reduced the remediation time by The plants were first grown in a non-salinized base solution for two 2-5 weeks indicating that well established ferns can remediate the flowering flushes, and then subjected to the mild salt stress, where water more rapidly. Considering the fern growth and As-uptake, the the patterns of water and total ion uptake were monitored over two least effective treatment combination was frond harvesting at 15-cm more flowering flushes. The stages of crop development (phenology) while continuously loading the ferns with As-contaminated water. were monitored by tracking the emergence and elongation of the Selectively harvesting only the senescing fronds and using clean flower shoots. As in previous reports with non-salinized rose plants, refill water was the most effective combination. In areas where clean the net uptake of water and ions, in both rootstocks, exhibited oscil- water is limiting, a combination of using As-contaminated refill water latory patterns over the course of each flowering flush. Water uptake and infrequent/no harvest is recommended for most cost effective was closely related to the development of new leaf area. Ion uptake As-phytoremediation. patterns were out of phase with water uptake, with the lowest uptake rates observed when the flowering shoots were showing their highest Specified Source(s) of Funding: Department, College, State and/or elongation rates. The highest ion uptake rates occurred as the shoots HATCH Private (Association, Foundation, Industry) Industry/As- approached the harvest stage. Diurnal (hourly) patterns of water and sociation Program Name, Award Number: Florida Power and Light ion uptake were also monitored at two distinct developmental stages. Inc., and Florida Agricultural Experiment Station Water uptake was minimal over the dark hours (10 pm to 8 am) and increased over the daytime, peaking at 2 pm. Total ion uptake followed a similar pattern, but interestingly its peak was out of synchrony with 9:30–9:45 am water uptake. For the diurnal cycle corresponding to the phenological Mixed Surface- to Subsurface-flow Constructed Wetland stage of maximum shoot elongation, ion uptake rates peaked between 4 pm and 8 pm. As the shoots approached the harvest stage, plant ion Systems Effectively Remediate Simulated Nursery uptake peaked between 2 pm and 6 pm. Data will also be presented Runoff for specific ions and for plants exposed to other salt formulations as Sarah A. White* well as in non-salinized plants. Clemson University, Pendleton SC; [email protected] Specified Source(s) of Funding: Department, College, State and/or Milton Taylor HATCH Private (Association, Foundation, Industry) USDA-CSREES Insectigen, Athens GA; [email protected] Rio Grande Basin Initiative 2005-34461-15661 Industry/Association Program Name, Award Number: J.H. Hill Foundation of the Interna- Ted Whitwell tional Cut Flower Growers Association Clemson University, Clemson SC; [email protected] Stephen J. Klaine Clemson University, Pendleton SC; [email protected]

1124 HORTSCIENCE, VOL. 43(4), JULY 2008 Nutrient rich runoff from nursery operation production areas can Specified Source(s) of Funding: Private (Association, Foundation, potentially impair downstream surface water quality. Constructed Industry) Department, College, State and/or HATCH wetland systems (CWS) are low, maintenance treatment systems that can reduce nutrient export. This investigation examined surface- to subsurface-flow CWS for nutrient removal efficiency. The surface- 10:00–10:15 am flow mesocosm treatment was established with three planting types: 1) Floating mats of typical wetland plants; 2) wetland plants rooted Chlorination Impacts on Tomato Transplants in into substrate; and 3) cultivars selected for nutrient uptake abilities. Production with Floatation Irrigation The subsurface-flow mesocosms were established with brick or in- Shubin Saha* dustrial mineral aggregate and then were either planted or unplanted. University of Florida, Gainesville; sksaha33@ufl.edu The floating treatment contributed the highest nitrogen removal efficiency (NRE, 97.3%), and the rooted treatment facilitated the great- Charles Vavrina est phosphorus removal efficiency (PRE, 82.1%). Selected cultivars SWFREC University of Florida, Immokalee FL; bobcat4f@ufl.edu were least efficient in both NRE and PRE. Planted subsurface-flow Daniel Cantliffe treatments NRE (95.6%) and PRE (94.9%) were consistently greater University of Florida, Gainesville; djcant@ufl.edu than the NRE (90.3%) and PRE (91.9%) of the unplanted treatments. Unplanted industrial mineral aggregate sorbed P more efficiently than Water quality and availability is a growing concern world-wide for the brick, resulting in lower effluent concentrations, 0.24 and 0.57 the production of food crops. One means of increasing the efficiency mg/L respectively. While planted treatments reduced P exports even of water utilized to grow crops is a closed irrigation system where further to 0.13 and 0.37 mg/L P for industrial mineral aggregate and water and nutrients are recycled. When water is recycled in plant brick respectively. Mixed surface- to subsurface-flow CWSs were production there is the increased likelihood of water-borne disease highly effective at reducing nutrient export. from Phytophthora sp. and Pythium sp. To reduce the risk of disease chlorination of the recycled solution is an option; however phytotox- Specified Source(s) of Funding: Federal competitive Federal Program icity is often associated with the use of chlorine. Three greenhouse Name, Award Number: USDA ARS Floriculture and Nursery Research experiments were conducted on tomato (Lycopersicon esculentum Initiative: Environmental Resource Management Systems for Nurseries, L.) seedlings in Immokalee, FL, with the objective of which de- Greenhouses, and Landscapes Agreement No. 58-6618-2-0209 termining chlorination impacts on transplant growth. Chlorination treatments (0, 1, 5, 10, 20, 40, 80 ppm) were applied via floatation irrigation to plants grown in flats with large and small cell sizes at 9:45–10:00 am both 3 and 5 weeks after seeding. Whole plant fresh weight, shoot ORALS–WEDNESDAY Uncertainty of Irrigation Schedules fresh weight, root fresh weight, leaf area, and whole plant dry weight Triggered with Soil Water Sensors in Florida Citrus was recorded. Treatments chlorinated at 40 and 80 ppm had lower (P < 0.05) leaf area and whole plant dry weight relative to the other Arnold Schumann* chlorination treatments. Shoot fresh weight for treatments chlorinated at University of Florida, Lake Alfred FL; schumaw@ufl.edu 5 ppm were not different (P < 0.05) than the control, however they were Laura Waldo greater (P < 0.05) as compared to all treatments chlorinated at a higher University of Florida, Lake Alfred FL; ljwaldo@ufl.edu concentration. Thresholds for chlorination of recycled water/nutrient solution for production of normal tomato transplants (5 weeks) were up One of the popular scientific methods for scheduling irrigation in to 20 ppm. Additional studies are required to determine thresholds for Florida citrus is based on volumetric soil water monitoring sensors other vegetable crops, impacts on various substrates, and chlorination installed in the root zone under tree canopies. There are several rates for sufficient management of water-borne diseases. dielectric devices on the market for measuring volumetric water content (VWC) of soil, but most of these sensors are “point” sensors Specified Source(s) of Funding: Department, College, State and/or because a very small percentage of the soil around a tree’s root system HATCH is measured. A limited soil volume is measured due to a small response radius around the sensors. The objectives of this study were to estimate the spatial variability of soil water measured under citrus trees 10:15–10:30 am with two different dielectric sensors, and to calculate the minimum Response of Indonesian Chili Pepper Varieties to number of sensors and configurations required for use in irrigation Irrigation Methods in Southern Taiwan scheduling. Measurements were taken with a 20-cm deep portable TDR moisture probe at 10-cm spacing in a 150 × 150-cm grid sampling area, Rosario Salas and with eight buried capacitance sensors on the same side of the tree AVRDC–The World Vegetable Center Shanhua, Tainan, Taiwan; rosario. as the irrigation nozzle. Using the 225 TDR moisture readings per tree, [email protected] geostatistics were utilized to map the soil moisture variability under Manuel Palada* the citrus tree canopies after several types of soil moisture changing AVRDC–The World Vegetable Center Shanhua, Tainan, Taiwan; events. Semivariogram analysis showed that the mean horizontal range [email protected] of spatial dependence for soil water was 40 cm, and coefficients of variation were high (19% to 56%). After both a long irrigation, or a Deng-lin Wu rainfall event, there was up to a three-day difference in the time it took AVRDC–The World Vegetable Center Shanhua, Tainan, Taiwan; for the eight buried probes under the tree canopy to reach the same [email protected] irrigation setpoint of 6.88% VWC. Consequently incorrect irrigation Paul Gniffke could cause agrochemical leaching, crop stress and ultimately yield losses or contamination of groundwater. The minimum number of AVRDC–The World Vegetable Center Shanhua, Tainan, Taiwan; TDR measurements required to reliably measure soil water content [email protected] in the same soil depth with an accuracy of 10% of plant available Integration of component technologies including multiple-disease water (PAW) and a 95% confidence level was 20 to 26. At least 2 to resistant varieties, improved crop management and drip irrigation has 4 capacitance sensors would be required to achieve the same level of the potential to reduce losses in chili pepper (Capsicum annuum) due confidence, and should be spaced more than 40 cm apart in order to to diseases such as anthracnose (Colletotrichum spp.), Phytophthora avoid spatial correlation. Better methods of measuring water status blight (Phytophthora capsici), bacterial wilt (Ralstonia solanacearum) using tree canopy stress or large soil volumes are being studied. and whitefly-transmitted geminivirus (WTG). A field experiment

HORTSCIENCE, VOL. 43(4), JULY 2008 1125 was established to: 1) compare yield performance of chili pepper hyphal colonization of ericoid mycorrhizal fungi in azalea roots was varieties grown under two irrigation systems (drip vs. furrow); 2) observed in Nutricote Total treated plants in comparison to non-in- identify multiple disease-resistant varieties and; 3) evaluate effects of oculated plants. While there was no significant decrease in nitrate irrigation system on disease incidence. Five varieties from Indonesia and phosphate concentrations in leachates collected from inoculated and one from AVRDC were grown on raised beds with plastic mulch and non-inoculated red oak and azalea plants, a noticeable decrease and irrigated with drip and furrow systems. Irrigation regime was in nitrate concentration was detected in inoculated plants treated with maintained at maximum soil moisture tension of -20 kPa for both Nutricote Total. The reduction in root biomass, nitrate, and phosphate systems. The experiment was laid out using split-plot in randomized concentration in leachates collected from Nutricote Total and Polyon block design with four replications. Based on a total of six harvests treated and inoculated Thuja plants could be explained by the increase over a period of 84 days, mean yield in drip irrigated plots was higher in the percentage of hyphal, arbuscules, and spore colonization of than furrow irrigated plots. Chili plants grown with drip irrigation Thuja roots, increasing nutrient uptake by the plants. produced greater dry matter, higher fruit number and larger fruit size compared to plants under furrow irrigation. Differences in plant Specified Source(s) of Funding: Federal competitive Federal Pro- characters were significant among varieties, but were not influenced gram Name, Award Number: NE-SARE, Research and Education, by irrigation methods. Principal pests attacking pepper plants during LNE07-265 this experiment included thrips, powdery mildew, and root rot due to Pythium spp. General observations showed that disease incidence was 10:30–10:45 am lower in drip than furrow irrigation. Water use efficiency was higher in drip than furrow irrigation. Although, this study was conducted in Survey of Forest Residual Availability for Nursery Taiwan, results can be applied in target countries where AVRDC has Production in the Southeast on-going projects. Cheryl R. Boyer* Specified Source(s) of Funding: Private (Association, Foundation, Auburn University, Auburn AL; [email protected] Industry) Thomas V. Gallagher Auburn University Auburn University AL; [email protected] Oral Session 25: Nursery and Ornamental Crops 2 Charles H. Gilliam Auburn University, Auburn AL; [email protected] Wednesday 23 July 10:15 am–12:00 pm Salon 10 Glenn B. Fain Moderator: Andrew G. Ristvey, [email protected] Auburn University, Auburn AL; [email protected] H. Allen Torbert 10:15–10:30 am USDA-ARS, Auburn AL; [email protected] Effects of Fertilizers and Naturally-Occurring Jeff L. Sibley Mycorrhizae on Sustainable Production of Nursery Crops Auburn University, Auburn AL; [email protected] Gladis Zinati* Rutgers University, New Brunswick NJ; [email protected] Residual chipping material (also called clean chip residual or CCR) has potential use as a growth substrate in the nursery and greenhouse John Dighton horticultural industries. A survey was conducted in the Southeast U.S. Rutgers University, New Lisbon NJ; [email protected] of companies conducting in-field chipping operations on pine planta- Rich Obal tions for the production of clean chips for pulp mills. Fourteen opera- tors in four states were visited to evaluate the availability of on-site Rutgers University, Freehold NJ; [email protected] residual material. Samples of CCR were taken from 10 sites. Samples James Johnson analysis revealed CCR is composed of about 37.7% wood, 36.6% bark, Rutgers University, Millville NJ; [email protected] 8.8% needles, and 16.9% indistinguishable (fine) particles. Survey participants estimated that approximately 27.5% of the site biomass is Jerome Frecon composed of CCR. Eight operations were able to sell some or all on-site Rutgers University, Clayton NJ; [email protected] CCR as fuelwood to pulp mills while 6 operations did not recover any Carl Nordstrom residual material, leaving 100% on the forest floor. Sample pH ranged New Jersey Nursery and Landscape Association, Bordentown NJ; from 4.3 to 5.5 which is slightly higher than the typical pH for pine [email protected] bark used in nursery production. Electrical conductivity levels were low, but acceptable in the samples from freshly chipped material. All Red oak, azalea, and Thuja plants were inoculated with naturally-oc- nutrients were generally within acceptable ranges with the exception curring ecto-, ericoid, and arbuscular mycorrhizal fungi, respectively, of Mn which was high at 4 of the 10 locations. Iron was high at 2 of using soil inocula. Plants were grown in #3 containers containing a the 10 sites. Significant variations in operations were observed among formulated mix of pine bark, peat moss, and sand (80:10:10) and the companies surveyed. Most companies were interested in making amended with 5% calcined clay particle size 5/20. Plants were fertilized CCR available to horticultural industries if profitable. with Osmocote 17-5-11, Nutricote Total 17-7-8, and Polyon 17-6-12 to supply 9.52 g N and compared to non-inocualted plants arranged Specified Source(s) of Funding: Private (Association, Foundation, in a RCBDesign. Plant top and root biomass, percent root coloniza- Industry) Industry/Association Program Name, Award Number: tion by mycorrhizal fungi, and nitrate and phosphate concentrations Horticultural Research Institute in leachates were determined. While there was no significant increase in top biomass of inoculated azalea and Thuja plants in comparison 10:45–11:00 am to non-inoculated, a significant increase in biomass was observed in inoculated red oak plants in all fertilized treatments. Similarly, root Physical and Hydraulic Properties of Douglas Fir Bark biomass increased significantly in inoculated red oak plants while Affected by Peat Moss and Pumice root biomass was slightly, but not significantly, reduced in inoculated Magdalena Zazirska* azalea and Thuja plants. The percentage of root colonization of red Oregon State Univ. North Willamette Research and Extension Center oak with ectomycorrhizal fungi increased in plants treated with either Aurora OR; [email protected] Nutricote Total or Polyon, providing higher diversity and greater chances of success in outplanting. Significant and higher percent

1126 HORTSCIENCE, VOL. 43(4), JULY 2008 James S. Owen, Jr. Our results show that water availability was surprisingly low in some Oregon State Univ. North Willamette Research and Extension Center, of these substrates and that most water is only available at matric Aurora OR; [email protected] potentials greater than 10 kPa, the point at which some studies have shown water stress in greenhouse crops. We have demonstrated that James E. Altland we can accurately monitor water availability in soilless substrates at USDA-ARS, Application Technology Research Unit, Wooster OH; james. these low matric potentials and schedule irrigations between 1 and [email protected] 10 kPa. Douglas fir bark (DFB), pumice, and Canadian sphagnum peat moss are Specified Source(s) of Funding: Department, College, State and/or the primary soilless substrate components used in the Pacific Northwest HATCH for woody ornamental containerized crop production, however little is know about their affect on substrate physical properties. Growing a fast, quality crop in a container requires soilless substrate to have 11:15–11:30 am the correct balance of air and water to maximize crop growth. The objective of this study was to investigate the physical and hydrologi- Horticultural Evaluation of the Lesser-known cal properties of three substrate components and their mixtures. The

Leatherwoods ORALS–WEDNESDAY experiment was a 3 × 3 factorial with three rates of peat and pumice William Graves* (0%, 15%, and 30%) mixed with DFB, creating nine different soilless Iowa State University, Ames; [email protected] substrates. Air spaces (AS), total porosity (TP), container capacity

(CC), and bulk density (Db), were determined using porometers. A Bryan Peterson* pressure plate extractor was used to partition CC into available (AW) Iowa State University, Ames; [email protected] and unavailable water (UAW, e1.5 MPa). Moisture characteristic curves (MCC) were generated by measuring water along a continuous 120 Matthew Helgeson cm column. These MCC were used to calculate easily available water Iowa State University, Ames; [email protected] (EAW) and water buffering capacity (WBC). The results indicate that, Although none of the three species of Dirca L. (leatherwood) is adding pumice to fir bark decreased or maintained equal CC, TP, AW, common in horticultural landscapes, two of the species are and WBC, but increased (Db. Adding peat to bark increased CC, TP and particularly obscure. Dirca occidentalis A. Gray is endemic in patchy AW, but decreased AS and (Db. The moisture characteristic curves for populations near the San Francisco Bay, and Dirca mexicana Nesom the soilless substrates with higher percentage of peat moss resulted in & Mayfield is known to occur in only one population in the Sierra increased container capacity with the largest proportion being EAW. Madre Oriental of northeastern Mexico. We observed these species in The addition of pumice to bark resulted in similar CC as bark alone, their natural habitats, propagated them from seeds, and con- however a greater proportion of water was easily available. These ducted experiments with seedlings in greenhouses and out- results will assist nursery growers in the Pacific Northwest to better doors to determine their responses to production practices and understand the physical properties of different substrate components their tolerances to environmental conditions. Monitoring over and their mixtures, and aid in their decision of which components two years showed air temperature where D. mexicana is in- should be used to create desired root environment for specific taxa digenous ranged from -2 °C to 35.5 °C, with weekly means of and production management regimes. 7.4 °C to 18.1 °C. Despite D. mexicana being restricted in the wild Specified Source(s) of Funding: Department, College, State and/or to such a mild climate, both it and D. occidentalis, which occurs in HATCH USDA plant hardiness zone 9, have survived winters where we planted them in trials near the interface of USDA zones 4 and 5. Seeds of both species germinated readily after cold stratification. The resulting seedlings were established in treatments of 12 media, one 11:00–11:15 am of which promoted growth and health ratings more than the others, Realizing Progressively Unavailable Water Content in and seedlings of D. occidentalis showed a linear increase in health Horticultural Substrates rating as the percentage of nitrogen supplied as nitrate vs. ammonium Andrew Ristvey* increased. Seedlings of D. occidentalis, the leatherwood species that our observations indicate is the showiest when in bloom, began to University of Maryland, Queenstown MD; [email protected] flower when they were as young as five years old. We conclude that Felix R. Arguedas D. occidentalis and D. mexicana are highly sensitive to horticul- University of Maryland, College Park MD; [email protected] tural production practices and to their placement in the landscape. Nonetheless, both species appear adapted for use beyond the limited John D. Le-Cox areas in which they are native. University of Maryland, College Park MD; [email protected] Specified Source(s) of Funding: Department, College, State and/or Horticultural substrates or soilless substrates are often erroneously HATCH named “potting soils ,” yet have very little in common with true soils, both physically and chemically. Soilless substrates exhibit special and important physical characteristics that allow plants to exist in poten- 11:30–11:45 am tially stressful environmental conditions, such as plastic containers. The components of soilless substrates are typically organic in nature, Growth and Physiology of Fraser Fir and but can also include processed inorganic and synthetic materials. Sub- Colorado Blue Spruce in Response to Mulch strate mixtures are typically created from two or more components, Bert Cregg* and each substrate combination has different physical characteristics Michigan State University, East Lansing; [email protected] that play a role in determining porosity and water-holding capacity. However other factors, such as container geometry and age, play a Pascal Nzokou significant role in determining these physical attributes. Water avail- Michigan State University, East Lansing; [email protected] ability in soilless substrates is quite different than in soils, and becomes progressively unavailable at very low matric potentials, typically two Ron Goldy magnitudes lower. We have performed water availability analyses on Michigan State University Extension Benton Harbor MI; [email protected] several substrates and substrate components using moisture sensors Weed control is a major concern for Christmas tree growers and (Decagon Devices, Pullman, WA) and a customized desorption table.

HORTSCIENCE, VOL. 43(4), JULY 2008 1127 landscape nurseries in the Midwestern United States. The overall goal of the present study is to determine the effect of plasticul- Oral Session 26: ture technology and other weed control techniques on growth and Fruit Crops 2: Culture and Management physiology of Fraser fir (Abies fraseri (Pursh) Poir.) and Colorado blue spruce (Picea pungens Engelm.) plantations. In Fall 2007 (two Wednesday 23 July 10:15 am–12:00 pm Salon 11 years after planting) seedling survival was high (88% or higher) for all Moderator: Julie Tarara, [email protected] treatments except non-irrigated + no weed control. The high overall survival rate is likely due to relatively frequent rainfall immediately after planting in 2006. Seedling caliper growth varied widely among 10:15–10:30 am treatments. Irrigation increased caliper growth compared to the non- Modeling the Effects of Processed-kaolin Particle Films irrigated plots, except for seedlings in the wood chip mulch treatment on Leaf and Whole-plant Physiology of Fruit Trees which grew as much as most of the irrigated treatments. Over the two years of the study height growth varied less than caliper growth, Soo-Hyung Kim* with differences most apparent between the non-irrigated + no mulch University of Washington, Seattle WA; [email protected] treatments and the irrigated or wood chip mulch plots. All of the David Michael Glenn mulches moderated soil temperature compared to the bare ground plots. USDA-ARS, Kearneysville WV; [email protected] In late July when daily high air temperatures were around 31 °C (88 °F), mean temperatures reached 38 °C (100.4 °F) on the bare ground Processed-kaolin particle films are commonly used in horticultural plots. Wood chip mulch reduced soil temperature by as much as 10 and agricultural crops to repel insects and to reduce heat stress and °C (18 °F)compared to bare ground. The reduction in soil tempera- solar injury. Numerous physiological benefits have been observed ture along with conservation of soil moisture resulted in comparable to result from the application of particle films in horticultural crops. growth between seedlings on plots with wood chip mulch without These benefits include improved whole-plant carbon assimilation, irrigation and seedlings on irrigated plots. The two black ground cov- water use efficiency, yield, and produce quality. Particle films alter ers; black plastic and mulch mats, had similar effects on soil tempera- leaf optical properties, and thus affect radiative transfer and energy ture. Effects of mulch on photosynthetic gas exchange were closely balance of the canopy. The reflectance and absorptance of a leaf in related to changes in moisture availability. Mulching with either plas- both photosynthetically active radiation (PAR) and near infrared tic or wood chips improved growth and physiological performance radiation (NIR) are altered by the particle films. Subsequent changes of both species and may be a viable alternative weed control strat- in radiation balance inside the canopy are likely to be an important egy. part of the underlying mechanisms responsible for the enhanced physiological responses due to particle films at the canopy scale. Specified Source(s) of Funding: Department, College, State and/or A mechanistic gas-exchange model that couples biochemistry of HATCH Private (Association, Foundation, Industry) Michigan State photosynthesis, physiological control of CO supply and water loss University Ag. Experiment Station Industry/Association Program 2 via stomatal conductance, and leaf energy balance has been applied Name, Award Number: Michigan Christmas Tree Association to elucidate how the changes in leaf optical properties due to particle film treatment are translated into physiological processes at both leaf and canopy scales. An empirically determined relationship between 11:45–12:00 pm the concentration of processed-kaolin particles and the leaf optical Application Position of Zeolite Affects Nursery Plant properties was incorporated into the coupled gas exchange model in Biomass order to account for the changes in short-wave radiation balance at the leaf surface. In combination with a radiative transfer model based on Gladis Zinati* sun-shade leaf classes, a canopy scale gas-exchange model has been Rutgers University New Brunswick NJ; [email protected] developed to examine the effects of particle films on whole-plant and The high cation exchange capacity (CEC) of natural zeolite provides canopy physiology. Model predictions are compared with gas-exchange better retention of cations in soilless container media and hence this data at leaf and canopy scales. The factors that are involved in how chemical property could increase nursery plant biomass and tissue the particle films influence leaf and canopy physiological processes nutrient retention. To test this hypothesis, three nursery plant spe- are discussed. Potential applications of the model are illustrated for cies: leucothoe, pieris, and chamaecyparis were grown outdoors in # assessing the conditions in which particle films can be effectively used 3 containers containing a formulated media of composted pine bark: to mitigate abiotic stresses on physiology of fruit trees. peatmoss: sand (80:10:10 by Vol.). Zeolite was applied at 70 grams per plant either as topdressed or placed at the bottom of plant root ball at time of transplanting to containers, compared to control (no 10:30–10:45 am zeolite) treatment and arranged in a randomized complete-block design Using Rest Breaking Agents and Dormancy Models with three replications. Top application of zeolite to chamaecyparis to Alter Bloom Timing in ‘French’ Prune: A Progress increased top and root biomass (by 14% and 27%, respectively) significantly in comparison to none and bottom application. A 23% Report increase was observed in leucothoe’s top biomass and a slight increase Franz Niederholzer* in root biomass in comparison to control. There was no significant Univ. of Calif. Cooperative Extension Yuba City CA; difference in pieris top biomass in any zeolite treatment, however, [email protected] there was a slight reduction in root biomass with the addition of zeolite at any position. Kitren Glozer Univ. of California, Davis CA; [email protected] Specified Source(s) of Funding: Department, College, State and/or HATCH Nursery management program A single cultivar, Improved French, comprises virtually all California prune (Prunus domestica) production. Adequate chilling and warm pre-bloom temperatures can limit the bloom period to 1-2 weeks across a growing region stretching 300+ km. Bloom temperatures >28 °C in key growing areas in 2004, 2005, and 2007 reduced statewide prune production by e50% in those years. While the cultivar’s chill requirement appears satisfied under California dormant season conditions (annual

1128 HORTSCIENCE, VOL. 43(4), JULY 2008 accumulation of >60 chill portions (CP) by the Dynamic Model of Erez 11:00–11:15 am and Fishman, 1998), economic viability of dried plum production in A Non-destructive Index (IAD) to Characterize Ripening California may benefit from rest breaking agents (RBAs) to advance bloom. RBAs are commonly used in temperate and subtropical fruit- Evolution in Fruit growing regions to advance and/or tighten bloom where insufficient Guglielmo Costa* chilling would otherwise render those crops unsustainable. However, Bologna University, Bologna, Italy; [email protected] effectiveness and predictability of this practice to advance bloom where Massimo Noferini chilling is adequate is not well defined. We are in the fourth year of a study to develop effective management of bloom manipulation and risk Bologna University, Bologna, Italy; [email protected] reduction of extreme heat at bloom. We advanced bloom timing with Giovanni Fiori horticultural oil or calcium ammonium nitrate + nonionic surfactant Bologna University Bologna, Italy; gfi[email protected] applied at certain CP accumulations in two of the first three years of this study and will present results from four years of replicated field Alice Tadiello studies. Challenges to developing predictable practices to manipulate Biology Dept Padua, Italy; [email protected] ‘Improved French’ prune bloom timing under California conditions Livio Trainotti will be discussed. Biology Dept Padua, Italy; [email protected] Specified Source(s) of Funding: Private (Association, Foundation, Giorgio Casadoro Industry) California Dried Plum Board Biology Dept Padua, Italy; [email protected] Vanina Ziosi 10:45–11:00 am Bologna University, Bologna, Italy; [email protected] Development of a Functional Relation Between Nutrients Fruit quality is commonly evaluated on the basis of flesh firmness, and Yield in Fertilizer Trial in Grape soluble solids content, and acidity. These parameters can be rapidly assessed, but they might not provide the information needed to Chandrasekhar Putcha accurately identify fruit ripening stage, especially if individually California State University, Fullerton CA; [email protected] considered. Other physiological, biochemical, or biomolecular pa- Radhakrishnamurty Putcha* rameters, such as ethylene emission, respiration, chlorophyll, mRNA Acharya N.G. Ranga Agriculture University, Hyderabad; amount of ripening-related genes could improve the information as

[email protected] they are related to the progression of ripening. These assays cannot ORALS–WEDNESDAY be routinely performed since they are costly and do not provide the D. Vijaya real-time information needed in the agronomic practice. Moreover, Acharya N.G. Ranga Agriculture University Hyderabad; all of the above-listed analyses require fruit destruction, thus, they are [email protected] performed on a few samples often not fully representative of the vari- Sreenivas Rao ability which is present on the tree or within fruit lots. In the present Acharya N.G. Ranga Agriculture University Hyderabad; United States work, a non-destructive index based on vis spectroscopy is introduced. [email protected] The Index of Absorbance Difference (IAD) is calculated as the difference in absorbance between two wavelengths near the chl-a peak; G. Ram Reddy modifications of the IAD are related to the changes in chlorophyll Acharya N.G. Ranga Agriculture University Hyderabad; United States content, ethylene emission, fruit quality traits, and transcription of [email protected] ripening-related genes that accompany the progression of ripening in stone (peach, apricot, and plum) and pome (apple and pear) fruit. This paper deals with effect of nutrients on subtropical fruit (grape). Thus, the IAD is a non-destructive marker of fruit biological age These results were obtained based on the field data collected as part more sensitive and confident than the physico-chemical parameters of a field experiment on fertilizer trial in grape conducted at Grape commonly used to describe the ripening process. The IAD is very research station in India. The nutrients considered were: Nitrogen (N), promising for practical applications along the whole fruit productive Phosphorous (P), and Potasium (K). Different doses of N, P and K chain, since it can be used to establish the optimal harvest time, to were administered to the grape plants to see their effect on the final grade harvested fruit according to their ripening stage, and to select the yield of grape measured in terms of kg/vine. These ranged from 0 to optimal postharvest strategy to adopt. In fact, fruit grouped according 150 for N, 0 to 100 for P, and from 0 to 150 for K. The units of these to the IAD are characterized by different storage or shelf-life potential, doses administered for various nutrients are: g/vine/year age of vine. quality at consumption, consumer acceptability, and responsiveness Total value of the dose NPK is calculated. These values are shown in to 1-methylcyclopropene application. the following row vector: NPK = [0 75 150 50 125 225 100 225 250 75 125 225 125 200 275 175 125 325 150 225 300 200 275 350 250 Specified Source(s) of Funding: Department, College, State and/or 325 100]t Where, t represents the transpose of the row vector. The HATCH Private (Association, Foundation, Industry) IFTA corresponding yield vector for the seedless germplasm(grape) is given below: Yield = [1.89 2.65 3.08 2.72 3.59 4.22 2.57 3.64 4.34 2.80 4.70 5.67 4.86 11.18 11.00 5.34 8.36 9.46 3.08 4.35 4.87 4.47 8.23 11:15–11:30 am 9.16 5.13 7.66 8.19]t The well known MATLAB has been used for statistical analysis. The following regression equations were obtained Trellis Tension Monitor for Continuous Growth and Yield between average yield(y) and the total value of NPK. The regression Information equation obtained is: y = 0.0199 x+ 1.4377. Where, y represents Julie Tarara* yield of grape and × represents the total NPK value. This result was USDA-ARS, Prosser WA; [email protected] also checked with the actual plot of data vs. the fitted linear equation. MATLAB has been successfully used to develop functional relation Paul Blom between yield parameter and total value of NPK. From this, one can USDA-ARS, Prosser WA; [email protected] use the principles of differential calculus and get the optimal value The ‘Trellis Tension Monitor’ (TTM) can be used for continuous of NPK for maximum yield. monitoring of growth and development in trellised crops, and for auto- Specified Source(s) of Funding: Department, College, State and/or matically predicting yield. The technology was developed initially for HATCH vineyards because juice processors and wineries require yield predic-

HORTSCIENCE, VOL. 43(4), JULY 2008 1129 tions and an indication of the “lag phase” in berry growth to better time 11:45–12:00 pm traditional hand sampling for these predictions. Rather than the static The Utility of Chlorophyll Fluorescence Parameters as estimates from hand sampling, the TTM provides a continuous trace and, thus, information about the dynamics of vine and berry growth. Indicator Tools for Citrus Greening Seventy-one TTMs were installed in 14 commercial and research Madhulika Sagaram* vineyards. A simple empirical model was used to estimate yield in the University of Florida, Lake Alfred FL; madhulika@ufl.edu current season as a function of the ratio of current tension in the trellis Jacqueline Burns wire to that from an antecedent season, and the known yield from the antecedent season. Estimated yield values stabilized well before lag University of Florida, Lake Alfred FL; jkbu@ufl.edu phase and the onset of ripening. The TTMs detected some expected The scope of the study was to verify the utility of leaf function mea- disturbances to the system like irrigation application, crop thinning, surement tools for early Huanglongbing (HLB) detection in citrus and dormant pruning. During the period of slow vegetative growth, genotypes using HLB-positive symptomatic, asymptomatic leaves crop thinning induced a decrease in wire tension proportional to the and HLB-negative leaves. We proposed to ascertain the utility of estimated decrease in crop mass. The accuracy of yield estimates non-destructive physiological parameters (chlorophyll fluorescence varied by trellis system and the initial sensitivity of the TTM, where and non-photochemical signatures) as indicator tools to identify higher initial tension values produced greater sensitivity to changes in infected trees during the early phases of the disease i.e. before mass. When physically constrained to a short segment of row (e.g., 3 symptom development. There was a very strong genotype effect on vines) TTMs produced accurate estimates of yield for the underlying all photochemical and non-photochemical signatures measured. The vines ( 5%), but were less representative of the remainder of the row. results indicated similar patterns for Fv/Fm, Y(II), 1-qp and NPQ in Unconstrained TTMs were less sensitive to systematic disturbances to Cleopatra mandarin, Sweet orange and Sweet lime; all of them being the trellis, but tended to produce more accurate yield estimates for the severely affected in this study. Other genotypes such as Persian lime, row. Over- and underestimates ranged from 1% to 20% in any given Eureka lemon and sour orange showed moderate chlorotic symptoms year. Results indicate the TTM provides useful real-time information and corresponding fluorescence measurements suggesting that cultivar on crop yield; however more ground-truthing is needed to improve differences may be important considerations when selecting suitable accuracy and the interpretation of anomalies in the tension trace. rootstocks and genotypes of citrus for planting or plant improvement Specified Source(s) of Funding: Department, College, State and/or purposes. Fv/Fm and Y(II) measurements indicated that they can be HATCH used to differentiate between symptomatic and asymptomatic leaves; and symptomatic and healthy leaves very effectively. However, these parameters could not effectively differentiate between asymptomatic 11:30–11:45 am and healthy leaves. NPQ and 1-Y measurements on the other hand Partial Root Zone Drying With and Without Salinity could be used to distinguish between asymptomatic leaves and healthy Affects Water Use Efficiency of Citrus leaves; but could not effectively discriminate between symptomatic and asymptomatic leaves in several genotypes. These results indicate Ayako Kusakabe* that NPQ could be used as a tool to identify citrus greening before University of Florida/IFAS, CREC Lake Alfred FL; ayako8@ufl.edu symptom development. However, further work and groundtruthing Juan Carlos Melga must be done to verify the strength of this tool for predictive purposes Citrus Research and Education Center, University of Florida–IFAS, Lake under a range of tree health and grove conditions. Alfred FL; [email protected]fl.edu Specified Source(s) of Funding: Department, College, State and/or Jill Dunlop HATCH Citrus Research and Education Center, University of Florida–IFAS, Lake Alfred FL; jdunlop@ufl.edu James P. Syvertsen Oral Session 27: Crop Physiology Vegetable Crops Citrus Research and Education Center, University of Florida–IFAS, Lake Wednesday 23 July 10:15 am–12:00 pm Salon 6 Alfred FL; jmsn@ufl.edu Moderator: Cyril Broderick, [email protected] A greenhouse experiment was conducted using partial root zone drying (PRD) with and without saline water on split-root Swingle citrumelo seedlings potted in an autoclaved fine sandy soil to evaluate leaf water 10:30–10:45 am use efficiency (WUE) and photosynthetic responses. There were five Yield and Phytochemical Responses to Deficit Irrigation treatments: 1) both root zone halves well watered (WW) with 50% and Plant Population of Spinach ETc with no NaCl (= total 100% ET control), 2) one split root zone irrigated with 100% ETc while the other received no water (PRD) or 3) Daniel Leskovar* 50% ETc water plus 50% ETc with 50 mN NaCl (PRS), 4) both sides Texas AgriLife Research, Vegetable & Fruit Improvement Center, Texas irrigated with 50% ETc plus 50 mM NaCl (SS); or 5) 50% ETc on one A&M System, Uvalde TX; [email protected] side and 50% ETc plus 50 mM NaCl on the other side (WS). Shoot Shinsuke Agehara growth was reduced similarly across all stress treatments. Relative to Texas AgriLife Reserach, Texas A&M System, Uvalde TX; WW, stomatal conductance was reduced least by WS and most by SS [email protected] but overall, stomatal conductance was not significantly associated with WUE. Photosynthesis and transpiration were also decreased most by Giovanni Piccinni SS. The reduced leaf photosynthesis in PRD, WS and PRS treatments Texas AgriLife Research, Texas A&M System, Uvalde TX; GPiccinn@ag. significantly reduced WUE, however, PRD plants only had slightly tamu.edu lower WUE than WW. Although PRD plants grew less than WW Kil Sun Yoo plants, leaves above the PRD dry side had higher photosyntheis than Texas A&M University-VFIC, College Station TX; [email protected] WW plants. In addition, higher photosynthesis and WUE occurred in leaves above the PRD dry side than above PRD wet side, and shoot Field studies were conducted to determine yield, leaf quality and phyto- growth showed the same pattern. Thus, PRD resulted in water savings chemical contents in response to deficit irrigation and plant population without loss of leaf function. of processing spinach (Spinacia oleracea L. cv. DMC 66-16). Spinach Specified Source(s) of Funding: Department, College, State and/or seeds were planted on Nov. 1, 2005, at plant populations ranging from HATCH 497,000 to 1,307,000 seeds per hectare. Three irrigation regimes were

1130 HORTSCIENCE, VOL. 43(4), JULY 2008 imposed with either a Center pivot or low pressure drip system (LPS); 11:00–11:15 am 100%, 75%, and 50% crop evapotranspiration rates (ETc) measured GA-induced Tuberization Signal Can Be Modulated by using ASCE Modified Reference ET formula and locally developed crop coefficients. Harvests were done on Feb. 28 and Mar. 1, 2006, Root Zone Calcium: Evidence For the Control of Tuber in the Center pivot and LPS, respectively. Total rainfall and irrigation Number by Calcium received were 213, 170, and 132 mm in the Center pivot, and 295, Sandra Vega 244, and 198 mm in the LPS, for the 100%, 75%, and 50% ETc rates, University of Wisconsin–Madison; [email protected] respectively. Under both systems, irrigation rate significantly affected marketable yield, yield components (P < 0.05) and phytochemical Jiwan Palta* contents (P < 0.10). Conversely, plant population and its interaction University of Wisconsin–Madison; [email protected] with irrigation rate were not significant for most measured parameters. John Bamberg Excess petiole growth, a negative quality component for the processing University of Wisconsin–Madison; [email protected] canning industry, was significantly reduced at 50% ETc under both irrigation systems. Water use efficiency was highest at 75% and 50% High GA level inhibits tuberization, and tuberization is promoted by ETc in the Center pivot and LPS, respectively. Ascorbic acid, B-caro- reducing GA level. Calcium is known to be a second messenger regu- tene, lutein, and neoxanthin consistently increased at 50% compared lating many developmental processes in plants. Signals such as light, to 100% ETc rate under both irrigation systems. The overall increase hormones, gravity, touch, wind, cold, drought, oxidative stress, and + in phytochemical contents in the Center pivot as compared to the LPS fungal elicitors have been linked to perturbation of cytoplasmic Ca2 was probably a response to greater stress since this system received concentration. Several studies have implicated that GA is transduced + an average of 43% less water (rainfall + irrigation) with less irrigation by an increase in Ca2 concentration and calmodulin levels. Using in frequency than the LPS. Deficit irrigation at 50% ETc significantly vitro propagated potato plantlets and continuously maintaining root reduced marketable yield by 53% and 17% in the Center pivot and zone calcium, we have recently demonstrated that tuber number and LPS, respectively. However, with the latter system, 51 mm of water tuber size are controlled by root zone calcium. It appears that a strong was saved by deficit irrigation at 75% ETc without a significant yield tuberization signal can be induced by lowering calcium around the reduction. Regulated deficit irrigation is a strategy that may save water developing stolon. The present study was conducted to investigate and improve phytochemicals in spinach. the possible relationship between root zone calcium and GA concentration in tuberization signal. For this purpose, we developed a Specified Source(s) of Funding: Department, College, State and/or system utilizing pure silica sand that allows precise control of root HATCH Federal competitive Federal Program Name, Award Number: zone chemical composition and monitoring of tuberization. Root zone Designing Foods for Health USDA CSREES 2004-34402-14768

calcium concentration was controlled by continuously supplying a ORALS–WEDNESDAY known solution as a drip. We were able to override the inhibition of tuberization by GA, by lowering extracellular calcium. As stated 10:45–11:00 am above, high GA inhibits tuberization. By lowering calcium we were Growth of Anamolous Placental Tissue in able to overcome the inhibitory effect of GA on tuberization. Our Capsicum chinense (Habanero) Pepper preliminary studies provide first evidence for the modulation of GA control of tuberization by extracellular calcium. These studies have a Fruit in Response to High Levels of Sulfur strong possibility of opening new avenues for understanding the role and Complete Fertilizer Nutrition of GA in the tuberization process. Cyril Broderick* Specified Source(s) of Funding: Department, College, State and/or Delaware State University, Dover DE; [email protected] HATCH Flowers Canada (Ontario) Ontario Centres of Excellence Capsicum peppers are a widely consumed vegetable that is rich in antioxidants and capsaicinoids, and types and varieties are grown around the world. Capsicum chinense types are known to be the richest in 11:15–11:30 am capsaicin, the predominant pungency compound, and fruit placentas Modeling Fruit Growth Dynamics of Cucumber, are now recognized the site of the synthesis of capsaicin. This work was designed to determine the effect of copious fertilization with Including Proportional and Dominant Growth Properties sulfur and complete fertilizer on fruit and capsaicin production in fruit of Individual Fruits within a Three-dimensional tissues. Transplants were bottom-dressed with 50 mg of sulfur dust Functional Structural Plant Model per plant, and each plant was copiously side-dressed two weeks later -1 Dirk Wiechers* with 10-10-10 fertilizer at approximately 250 kg·ha . The Capsicum Leibniz Universität Hannover, Institute of Biological Production Systems. chinense Var. Habanero pepper seedlings were planted in rows 120 cm Hannover, Germany; [email protected] apart and 60 cm between plants in a split-plot design at the Delaware State University (DSU) Outreach and Research Center in Smyrna, Katrin Kahlen Delaware. There were some 15 plots of four plants each. The plants Leibniz Universität Hannover, Institute of Biological Production Systems. were watered and maintained until mature. At harvest, data showed Hannover, Germany; [email protected] that 70.55 ± 2.0 percent of the samples of sulfur bottom-dressed plants Hartmut Stützel had fruits with anamolous placental tissue growth. In the non-treated plants, only 27.22 ± 1.8 percent of the samples of untreated plants Leibniz Universität Hannover. 30419 Hannover, Germany; stuetzel@gem. had fruits with some anomalous placental growth. Even though the uni-hannover.de non-bottom dressed plants were planted in separate holes from the Goutam Kuwar bottom-dressed plants, the effect that some roots of the non-treated Leibniz Universität Hannover. Institute of Biological Production Systems plants obtained some of the high sulfur treatment to affect placental Hannover, Germany; [email protected] growth in the non-treated plants. Differences between treated and non-treated plants were consistently high and significant, thereby One of the major production characteristics of cucumbers are the dy- indicating that the effects are real. namically changing patterns of fruit growth and abortion. The study presented here was designed to analyze the dry matter partitioning Specified Source(s) of Funding: Department, College, State and/or processes to be incorporated into a highly detailed three-dimensional HATCH functional structural plant model (3D FSpm) suitable to predict light interception and photosynthesis of a row canopy-like cucumber. The presented work focuses on modeling fruit dry matter partitioning.

HORTSCIENCE, VOL. 43(4), JULY 2008 1131 The main assumptions are that a moderate limitation of assimilates 11:45–12:00 pm results in proportional growth which can be described by a limitation Accumulation of Lycopene as an Indicator of Maturity in factor, whereas severe assimilate limitation causes dominating fruit growth of older fruits, implemented in to the model by a dominance Personal-Size Melons factor. The allocation model was based on the hypotheses that the Edgar Vinson* limitation factor is related to the source strength and the dominance Auburn University, Auburn AL; [email protected] factor to the individual organ sink strength. Two different experiments Floyd Woods were conducted for model parameterization and repeated for model evaluation. The first experiment was carried out to determine the Auburn University, Auburn AL; [email protected] maximum fruit growth rate and contained a variation of source size, Penelope Perkins-Veazie the second one to derive the limitation and dominance factors and USDA-ARS-SCARL, Lane OK; [email protected] contained a variation of sink size. The examination of the predicted and experimentally derived limitation and dominance factors shows Joseph Kemble that the predictions are in line with the evaluation measurements. Thus, Auburn University, Auburn AL; [email protected] the results support the hypotheses for the limitation and dominance Angela Davis factors. Source availability can very likely explain the proportional USDA, ARS, South Central Agricultural Research Laboratory Lane OK; growth in terms of the limitation factor, whereas the individual sink [email protected] strengths explain the dominant growth properties of fruits. Future work has to show that the suggested model approach is capable to mimic Wheeler Foshee the typical fruit growth patterns in greenhouse cucumber production Auburn University, Auburn AL; [email protected] systems within a 3D FSpm. Jason Burkett Specified Source(s) of Funding: Federal competitive German Research Auburn University, Shorter AL; [email protected] Foundation (DFG) Significant health benefit can be derived from consumption of fresh fruit such as watermelon which are high in lycopene content. There- fore it is desirable to determine lycopene content of watermelons at 11:30–11:45 am various stages of development in order to harvest at optimal levels. Simulating the Effects of Training Systems, Plant Previous studies have characterized changes in lycopene content in Density and Plant Distribution on Cucumber Canopy watermelon. In the present study, lycopene and beta carotene content Architecture using a Three-Dimensional Functional- were determined in ‘Valdoria’ and ‘Vanessa’ personal-sized watermelons at 20, 30, 40, and 50 days post anthesis (DPA). In addition, Structural Plant Model physicochemical attributes such as pH, titratable acidity (TA), and Katrin Kahlen* soluble solids (°Brix) were also determined. High sugar:acid ratios Leibniz Universität Hannover.r, Institute of Biological Production Systems are potentially associated with optimal fruit flavor and palatability. In Hannover, Germany [email protected] both cultivars, lycopene content peaked at 30 DPA while the sugar:acid ratio peaked at 40 DPA. The data suggest that, in order to obtain the Hartmut Stützel maximal health benefit derived from watermelon consumption, fruit Leibniz Universität Hannover. 30419 Hannover, Germany stuetzel@gem. flavor may, to some extent, be sacrificed. In this study, beta carotene uni-hannover.de content increased over time. In ‘Vanessa’, beta carotene content was Dirk Wiechers highest at 40 and 50 DPA indicating that, potentially, watermelons Leibniz Universität Hannover., Institute of Biological Production Systems were overripe, which coincided with maximal sugar:acid ratios. Ad- Hannover, Germany [email protected] ditional studies are needed in order to definitively correlate lycopene and beta carotene with various physicochemical indicators. Such Plant training regimes in greenhouse cucumber production aim at information would assist in determining an improved convergence increasing the productivity of the cultivation system. All plant training of these maturity indices. manipulation affect canopy architecture, which, in turn, may trigger adaptation processes on organ level. Cucumber leaves in particular show Specified Source(s) of Funding: Department, College, State and/or a high developmental plasticity. This work presents the concepts of a HATCH three-dimensional functional-structural plant model used to simulate the canopy architecture with respect to training system, plant density and plant distribution. The dynamic structural plant model is based on a parametric Lindenmayer system, which interacts with a light model Oral Session 28: Postharvest Physiology/Quality/Disease that provides local flux density of photosynthetically active radiation Wednesday 23 July 10:45–11:45 am Salon 7 and red to far-red ratios. Two main model features mimic the light response of individual leaves: 1) the photosynthetic efficiency of the Moderator: Jun Song, [email protected] single leaf is dependent on the irradiance incident on the leaf; and 2) developmental plasticity allows for light-foraging by horizontal leaf 10:45–11:00 am movement through petiole bending and expansion of internodes and petioles in response to the light environment. Graphical simulation Efficacy of Disinfectants Is Affected by Endogenous outputs give realistic views on the effects of training system, plant Microbial Population on Fresh-cut Vegetables density and plant distribution on canopy architectures. The simula- Hidemi Izumi* tions show that new canopy properties appear if a training system Kinki University, Kinokawa, Japan; [email protected] is chosen that does not disturb morphological adaptation processes. Future model work will be to include the effects of practically relevant Kaori Sera factors like CO2, which is a further mean to increase the efficiency Kinki University, Kinokawa, Japan; [email protected] of the cultivation system. Yuji Yamamoto Specified Source(s) of Funding: Department, College, State and/or Kinki University, Kinokawa, Japan; [email protected] HATCH Sumithra Wendakoon Toyo College of Food Technology, Kawanishi, Japan; [email protected]

1132 HORTSCIENCE, VOL. 43(4), JULY 2008 Effects of endogenous microbial population on microbicidal effective- ing/antioxidant power (FRAP value based on ascorbic acid) increased ness of some disinfectants were determined for fresh-cut cabbage and by 40% to 50% from 12.8 and 12.9 to 20.7 and 22.8 mol/FWg in white cucumber. Cabbage shreds were prepared from cabbage heads with to pink fruit, whereas in the red fruit they decreased to 18.9 and 18.2 low microbial population (3.6 log CFU/g of mesophiles counts) and mol/g, respectively. No significant difference was found in oxygen those with high microbial population (4.8 log CFU/g of mesophiles radical absorbing capacity (ORAC value based on Trolox equivalent) counts) after 2 days storage at 20 °C, and treated with 0.3% fumaric among fruit of different maturities. acid agent (0.06% of fumaric acid), 0.05% calcined calcium agent (0.046% of calcium) with subsequent washing with ozonated water Specified Source(s) of Funding: Department, College, State and/or (5 ppm of ozone), or water (control). These treatments were effective HATCH in reducing counts of mesophiles, coliforms, and fungi, and the effect was greater for shreds with low microbial population than those with 11:15–11:30 am high microbial population. The number of bacterial species detected in shreds was less in treated samples than in water-dipped controls. Aromatic Profile of ‘Galia’ Muskmelon The treatments eliminated some endogenous bacteria such as the Jeanmarie Mitchell* genera Bacillus, Microbacterium, Escherichia, and Pantoea. Whole University of Florida, Gainesville; jmitche@ufl.edu cucumbers containing low microbial population (4.6 log CFU/g of mesophiles counts) or high microbial population (5.4 log CFU/g of Daniel Cantliffe mesophiles counts) were prepared by treatment with ozonated water University of Florida, Gainesville; djcant@ufl.edu (5 ppm) or water, respectively, and then sliced. The slices were treated Harry Klee with 0.05% fumaric acid agent (0.01% of fumaric), 0.01% mustard University of Florida, Gainesville; [email protected]fl.edu and hop extract agent (0.001% of allyl isothiocyanate and beta-acid) followed by ozonated water (5 ppm), or water (control). Slices treated Steven Sargent with mustard and hop extract agent followed by ozonated water had University of Florida, Gainesville; sasa@ufl.edu decreased counts of coliforms only with slices with low microbial popu- Peter Stoffella lation. With other treatments, there were no pronounced antimicrobial effects when compared with water-dipped controls. The diversity of University of Florida, Fort Pierce FL; pjs@ufl.edu bacterial flora of slices was similar among all samples. These results Denise Tieman indicate that initial microbial counts on whole vegetables should be University of Florida, Gainesville; dtieman@ufl.edu reduced to enhance the antimicrobial efficacy of disinfectants for Cucumis melo Reticulatus fresh-cut vegetables. ‘Galia’ muskmelon ( L. var. Ser.) is recog- ORALS–WEDNESDAY nized for its exceptional flavor and musky aroma. Recently marketed Specified Source(s) of Funding: Department, College, State and/or Galia-type muskmelons are firmer, but flavor has been compromised HATCH in breeding efforts to increase firmness. To determine what has set ‘Galia’ flavor apart from Galia-types, this research focused on aroma,

and sought to identify the volatile compounds of the true ‘Galia’ F1 11:00–11:15 am hybrid. To evaluate aroma development, fruits were harvested at four Anthocyanins, Phenolics, Flavonols, and maturity stages: 1) zero-slip, green (ZG); 2) zero-slip, yellow-green Antioxidant Capacity of ‘Honeoye’ and ‘Mira’ (ZYG); 3) half-slip (HS); and 4) full-slip (FS). At each stage, quality Strawberry Fruit at Different Harvest Maturities factors (size, soluble solids content (SSC), and firmness) ethylene and respiration rates were measured. The ‘Galia’ muskmelon results Jun Song* were then compared to two Galia-types (GT), MG10183 and ‘Elario’. Agriculture and Agri-Food Canada, Kentville NS Canada [email protected] GC/MS and GC/FID verified 38 aroma compounds. Of these, 13 to 17 Rong Cao compounds significantly contributed to the aromatic profile, depending Agriculture and Agri-Food Canada, Guelph ON Canada [email protected] on stage. Increases in aroma volatiles were observed as fruits ripened and after storage. ‘Elario’ had the highest total aromas at every stage. Rymond Yang ‘Galia’ had higher volatiles at stages ZYG and HS than MG10183, Agriculture and Agri-Food Canada, Guelph ON Canada [email protected] yet by FS, both cultivars had similar aroma values. Most fruit quality attributes, ethylene and respiration rates were similar among all Leslie Campbell-Palmer genotypes at stages ZG and ZYG. At HS, MG10183 had greater SSC Agriculture and Agri-Food Canada, Kentville NS Canada Campbell- (10.8 °Brix) than ‘Galia’ (9.4 Brix) and ‘Elario’ (8.6 °Brix). Also [email protected] at HS, both GTs were firmer than ‘Galia’. Although ethylene rates Strawberry fruit (Fragaria ananassa D.) is one of the most popular were similar among all types, respiration rates were higher for GT fruits in the world. Anthocyanins, phenolics, and flavonols are the muskmelons. At FS, ‘Galia’ had similar SSC (10 Brix) to both GTs, major bioactive compounds in strawberry fruit, particularly in human but MG10183 had greater SSC (11.2 < °Brix) than ‘Elario’ (9 Brix). nutrition and disease prevention. Various researches have indicated that ‘Galia’ was less firm than both GTs, while all ethylene and respiration phytochemical composition of strawberry fruit is affected by factors rates were similar at FS. Although ‘Elario’ had the highest total aroma such as the production environment, cultivar, fruit ripening and stor- values, it was not the sweetest cultivar. age condition. In this study, strawberry fruit of cultivars ‘Honeoye’ and ‘Mira’ were harvested twice at three developmental stages based on fruit color (white, pink, and red). Investigations were repeated 11:30–11:45 am over two seasons and evaluated for changes in anthocyanins, ellagic Developmental Changes in Free Amino A acid, phenolics, flavonols, and the antioxidant capacities in relation to cid Content in Ripening ‘Jonagold’ Apple Fruit as fruit ripening. Anthocyanins, total phenolics, and flavonols increased Related to Branched-chain Ester Production as fruits ripened from white to red. Cyanidin content increased from undetectable in white fruit to 78.6 and 99.9 g/g FW in red ‘Honeoye’ Nobuko Sugimoto* and ‘Mira’ fruit, respectively, while procyanidins decreased from 25.9 Michigan State University, East Lansing; [email protected] and 23.1 g/g FW in white fruit to undetectable levels in red fruit. The Randy Beaudry total phenolics and ellagic acid increased from 37.5 and 33.6 to 125.9 Michigan State University, East Lansing; [email protected] and 100.7 g/g FW in white and red fruits, respectively. Hydroxycin- namic acid and other flavonols were only detected in the red fruit in The relationship between the free amino acid content and the branched- both cultivars. The antioxidant capacities measured as ferric reduc- chain ester production during ripening and senescence in ‘Jonagold’

HORTSCIENCE, VOL. 43(4), JULY 2008 1133 apple fruit (Malus × domestica Borkh) was studied. Twenty amino acids 11:00–11:15 am were measured by liquid chromatography coupled with tandem mass Effects of Supplemental Light Quality on Growth spectrometry (LC-MS/MS). Several patterns in amino acid content were observed. Several amino acids (alanine, arginine, asparagine, aspartate, and Phytochemicals of Baby Leaf Lettuce glutamine, glutamate, serine, and threonine) decreased by 5-7 fold. A Grown under White Light few amino acids (leucine, tryptophan, and valine) increased moderately Qian Li* by 2-3 fold. Phenylalanine and methionine contents decreased as fruit University of Arizona, Tucson; [email protected] began to ripen and gradually increased during senescence. The decline in methionine may be related to its diversion to ethylene biosynthesis. Chieri Kubota* The concentration of several amino acids (histidine, lysine, proline, The University of Arizona, Tucson; [email protected] tyrosine, and tryptophan) peaked in concert with the peak in the Using UV-A, blue (B), green (G), red (R), and fared (FR) LEDs (CCS respiratory climacteric. The major branched-chain ester precursor, Inc, Japan), we investigated the effects of different supplemental light isoleucine, increased more than 20-fold as branched-chain ester syn- qualities on growth and phytochemicals of ‘Red Cross’ baby leaf let- thesis increased. The data suggest that an increase in isoleucine was tuce (Lactuca sativa L.) grown under white fluorescent lamps inside a required for production of the major apple esters, 2-methylbutanoate growth chamber. UV-A, B, G, or R photon flux of supplemental LEDs and 2-methylbutanol during ripening. The lack of parallel increases was 20, 120, 120, 120, and 160 mmol·m-2·s-1 respectively, while PPF in isoleucine and threonine, the precursor to isoleucine, suggests that was adjusted to 290-300 mmol·m-2·s-1 in all treatments. Other growth threonine conversion was enhanced, bringing about its depletion, or chamber conditions common to all treatments include 25 C/15 °C that isoleucine synthesis may have been enhanced through an alterna- day/night temperature and 16 hour photoperiod. After 12 days of tive pathway. light quality treatment (26 days after germination), fresh and dry Specified Source(s) of Funding: Department, College, State and/or weight, stem length, and leaf length of lettuce plants were enhanced HATCH Multi state regional project by 33% to 111% under the supplemental FR light, compared to those in control (PPF = 300 without supplemental LEDs), presumably due to enhanced light interception by enlarged leaf. Anthocyanin concentration was significantly increased by 21% to 24% under suppl. Oral Session 29: Controlled Environment 2 UV-A or B light, but reduced by 20% under suppl. FR light. Under Wednesday 23 July 10:45 am–12:00 pm Salon 12 suppl. R light, total phenolics was significantly increased by 26%, but chlorophyll concentration was significantly reduced by 27%. Xantho- Moderator: Youbin Zheng, [email protected] phyll concentration was reduced by 26% to 36% under suppl. UV-A, B, or G light, and beta carotene concentration was reduced by 15% 10:45–11:00 am to 25% under suppl. UV-A, B, or G light and by 47% to 60% under suppl. FR or R light. Vitamin °C was reduced by 23% under suppl. FR Nutrient Solution Oxygenation in Soilless Production light. Although the mechanisms of changes in phytochemicals under Youbin Zheng* different supplemental light quality are not well known, the results University of Guelph, ON Canada; [email protected] demonstrated that supplemental light quality could be strategically used for enhancing growth and nutritional value of baby leaf lettuce Linping Wang grown under white light. University of Guelph, ON Canada; [email protected] Specified Source(s) of Funding: Department, College, State and/or Sally Martinez HATCH University of Guelph, ON Canada; [email protected] Mike Dixon 11:15–11:30 am University of Guelph. ON Canada; [email protected] Influence of R/B Ratio in LED Light Quality on Growth A well oxygenated root zone is essential for a healthy root system and Development of Lettuce (nutrient uptake and root growth/maintenance), and the prevention of root borne diseases. Oxygen deficiency in the root zone can lead Wen Jing to poor root and plant performance and an increase in the incidence The Chinese Academy of Agricultural Sciences Beijing, China; of disease. There is a wealth of information in the literature regard- [email protected] ing the effects of oxygen deficiency in the root zone, but very few Bao Shunshu* studies have been conducted that focus on the response of plants to The Chinese Academy of Agricultural Sciences Beijing, China; oxygen enrichment, particularly root zone or nutrient solution oxygen [email protected] enrichment. Modern technologies can supersaturate nutrient solution with oxygen in soilless production system; however, there are no reli- The ratio of red (R) to blue (B) was studied to investigate the influ- able data to guide growers when applying these technologies. At the ence of R/B ratio on the growth and development of lettuce (Lactuca University of Guelph, we have conducted extensive research on the sativa L.). The experiment was conducted under controlled daytime responses of plants to nutrient solution oxygenation in the past few temperature by 25 ± 1 , night temperature by 15 ± 1 , relative humidity -1 years. The experiments include: 1) physiology and growth responses by 60~80%, CO2 concentration by 1500 ± 50 mol·mol , light intensity of tomato, cucumber, and miniature rose seedlings to nutrient solution by 150 ± 11 mol·m-2·s-1and photoperiod by 12 h/d. The lettuce was oxygenation (9, 20, 30, and 40 mg·L-1); 2) plants response to pythium planted by the hydroponic cultivation. The light emitting diode (LED) under different root zone oxygen levels; 3) cut rose production and composed by red light LED whose wavelength was 660 nm and blue nutrient solution oxygenation in drip irrigation system; 4) miniature light LED whose wavelength was 450 nm were used as lighting source. rose and nutrient solution oxygenation in subirrigation system; and 5) Three treatments were designed with LED1(R/B=10), LED2(R/B=8) cucumber growth and yield responses to nutrient solution oxygenation. and LED3(R/B=6) using LED light quality respectively, compared to This paper will provide a summary of our research findings on nutrient treatment of fluorescent lamp for 30 days. The net photosynthetic rate, solution or root zone oxygenation. vitamin °C contents and fresh weight were the highest, and the nitrate contents was the least in LED2. The quality and growth of lettuce in Specified Source(s) of Funding: Department, College, State and/or LED2 were better than other treatments. HATCH Flowers Canada (Ontario) Ontario Centres of Excellence Specified Source(s) of Funding: Department, College, State and/or HATCH

1134 HORTSCIENCE, VOL. 43(4), JULY 2008 11:30–11:45 am and root dry rates than substrates containing GRH. Vinca grown in Influence of Lighting Intensity on Dendrobium officinale peat regardless of the rate of perlite, bark, or PBH had higher plant height, shoot fresh weight, and root fresh weight than plants grown in In Vitro Under Closed Plant Factory root substrates containing GRH. Vinca root dry weights were higher Bao Shunshu* for those plants grown in peat versus GRH. Overall, GRH was not a The Chinese Academy of Agricultural Sciences, Beijing, China bao. suitable alternative to peat when 60% to 100% of the total volume of [email protected] the root substrate was GRH. Dongxian He* China Agricultral University, Beijing, China [email protected] Guo Shunxing Oral Session 30: Institute of Medicinal Plant Development, Peking Union Medical College, Genetics/Germplasm/Plant Breeding—Cross-Commodity Chinese Academy of Medical S., Beijing, China [email protected] Wednesday 23 July 3:30–5:15 pm Salon 7 Yang Qichang* Chinese Academy of Agricultural Sciences, Beijing, China yangq@cjac. Moderator: Kim Hummer, [email protected] org.cn 3:30–3:45 pm The influence of lighting intensity on Dendrobium officinale in vitro was studied under controlled temperature, humidity, CO2 concentration Early Growth, Leaf Yield, Protein Content, and Pod and photoperiod in a closed plant factory. Single D. officinale explants Yield of Four Moringa Accessions in Hawaii each with 300 mg fresh mass were planted in polycarbonate culture Theodore J.K. Radovich* vessels. Cultural vessels with volume of 380 ml was filtered by two University of Hawaii, Honolulu HI; [email protected] 10 mm gas-permeable filters on the vessel tops. Four treatments with lighting intensities by 37, 68, 92, and 120 µmol·m-2·s-1, respectively, Robert E. Paull were controlled at air temperature by 24 ± 1, relative humidity by University of Hawaii, Honolulu HI; [email protected]

65 ± 5%, photoperiod by 12 h/d, and CO2 concentration by 800 ± 50 µmol·m-2·s-1 for 92 days. The growth of D. officinale in vitro were The leaves of Moringa oleifera and M. stenopetala are well regarded better in the treatment with lighting intensity of 68 µmol·m-2·s-1 and for their high concentration of nutrients, particularly protein. The pods were shown in photoinhibition over lighting intensity by 92 µmol·m- of M. oleifera are also consumed and the seeds yield a high value oil 2·s-1. The polysaccharide contents increased with the addition of light- that has potential culinary, cosmetic and biofuel applications. Three ORALS–WEDNESDAY ing intensity less than 92 µmol·m-2·s-1, but no significant differences accessions of M. oleifera (‘PKM-2’, ‘Hawaii-1’, ‘Hawaii-2’) and a were found between treatments with lighting intensities by 68 and single accession of M. stenopetala were grown at two locations with 92 µmol·m-2·s-1. three replications on the island of Oahu. Seedlings were transplanted two months after seeding and height measured periodically for more Specified Source(s) of Funding: Department, College, State and/or than six months. At 180 days after transplanting, 5 trees were coppiced HATCH in each replication (30 trees per accession) and final plant height, leaf yield, immature pod yield and leaflet crude protein content determined. Pods were allowed to mature on the remaining uncoppiced trees and 11:45–12:00 pm collected to determine final pod size, seed yield, and oil content. Performance of Processed Parboiled Fresh-Ground Rice Growth rates were fastest in the M. oleifera accessions. Final height of M. oleifera trees (4.7-5.1 m) were almost twice that of M. stenopetala, Hulls as an Alternative Soilless Root Substrate while leaf yield was greatest in M. stenopetala. Among the M. oleif- Johann Buck* era accessions, leaf yield of ‘Hawaii-1’ and ‘Hawaii-2’ were similar University of Arkansas, Fayetteville AR; [email protected] 1st Author to each other and 54% higher than ‘PKM-2’. Average crude protein concentrations were similar among M. oleifera accessions (~33%) Michael Evans and lowest in M. stenopetala (26%). Pod and seed yield followed the University of Arkansas, Fayetteville AR; [email protected] order ‘PKM-2’ > ‘Hawaii-2’ > ‘Hawaii-1’. M. stenopetala did not Paolo Sambo flower during the period evaluated. The data strongly suggested that University of Padova, Venice, Italy; [email protected] variability within Moringa germplasm needs to be more thoroughly evaluated in order to optimize production of different Moringa com- Thirty root substrates were formulated by blending perlite, composted modities (i.e. leaf, immature pod and oil) in the U.S. pine bark (bark) or parboiled fresh rice hulls (PBH) at a rate of 0%, 10%, 20%, 30%, or 40% (v/v) with the remainder of the volume be- Specified Source(s) of Funding: Department, College, State and/or ing either sphagnum peat (peat) or processed parboiled fresh-ground HATCH Federal competitive Federal Program Name, Award Number: rice hulls (GRH). ‘French Boy Yellow’ marigold (Tagetes patula), Tropical and Sub-Tropical Agricultural Research Program (TSTAR- ‘Seed Score Red’ geranium (Pelargorium × hortorum), and ‘Cooler USDA) Grape’ vinca (Catharanthus roseus) plugs were transplanted in 10-cm containers filled with the substrate and grown during Spring and Fall 2007. The plant height, shoot fresh weight, shoot dry weight, root fresh 3:45–4:00 pm weight, and root dry weight were measured, weighed, and recorded Ribes Bloom Phenology in a Diverse Field Genebank at the end of each growing period. For marigold, regardless of rate of perlite, bark, or PBH, the plant height, shoot fresh weight, root fresh Daniel Dalton* weight, and root dry weight were higher for plants grown in substrates Oregon State University, Corvallis OR; [email protected] containing peat vs. GRH. The shoot dry weights for marigold grown Kim Hummer* in substrates comprised of peat and containing 0% perlite, bark, or USDA-ARS, Corvallis OR; [email protected] PBH were higher than those substrates comprised of 10%, 20%, 30%, or 40% perlite, bark, or PBH. Geranium plant height was highest for Cultivars of currants and gooseberries (Ribes) vary in self-compatibility. those plants grown in peat mixed with perlite. Geranium grown in Pollinizers are used to maximize fruit set of commercial plantings. For peat regardless of the rate of perlite, bark, or PBH tended to have natural cross-pollination to be effective, two or more cultivars must higher shoot fresh weights, shoot dry weights, root fresh weights, be compatible and bloom synchronously. Geneticists have additional

HORTSCIENCE, VOL. 43(4), JULY 2008 1135 interests in determining flowering phenology of Ribes species for breed- supports the study of plant origins, characteristics of cultivated plants ing. The objective of this study is to document relative bloom time and and provides a mechanism to contrast cultivated environments with duration in a globally diverse Ribes collection in the field genebank at those of natural populations. It identifies commercial sources for many the U.S. Department of Agriculture, Agricultural Research Service, in botanic garden plants while providing insights in to plant propagation Corvallis, OR. Dates of first, full, and last bloom were recorded in 1999, protocols. Data users may search records from one or more institutions 2007, and 2008. Observations were recorded weekly on 317 cultivars to create reports, maps, and images. of gooseberries (R. uva-crispa), jostaberries (R. nidigrolaria), black (R. nigrum), golden (R. aureum), ornamental (section Calobotrya), and Specified Source(s) of Funding: Private (Association, Foundation, red currants (R. rubrum), including representatives of 60 species. A Industry) Federal competitive Industry/Association Program Name, 40-day bloom duration was observed in R. sanguineum. These orna- Award Number: Anonymous donor Federal Program Name, Award mental currants had the earliest bloom date and longest duration, and Number: Institute of Museum and Library Services National Leadership were followed by gooseberries, red currants, jostaberries, and black in Building Digital Resources grant number LG-24-05-0018-05 currants, which began blooming later and had shorter bloom duration. Ribes hudsonianum var. petiolare and R. lacustre had the latest bloom 4:15–4:30 pm dates. The latest flowering gooseberries included R. uva-crispa cvs. ‘Rokula’ and ‘Trumpeter.’ Black currant R. nigrum cvs. ‘Ben Alder,’ Diversity of Wild Malus Germplasm Available in the ‘Ben Tirran,’ and three selections from the Five Aces breeding program USDA-ARS National Plant Germplasm System in Maryland were among the latest flowering black currants. Flowering Gayle Volk* time varied between years, occurring 2-3 weeks earlier in 2007 than USDA-ARS National Center for Genetic Resources Preservation, Ft. Col- in 1999 and appeared to be linked to degree-day accumulation. These lins CO; [email protected] data will be useful to breeders for developing new cultivars and for growers to design plantings to maximize cross-pollination and fruit Philip Forsline production of Ribes crops. Plant Genetic Resources Unit, Geneva NY; [email protected] Specified Source(s) of Funding: Private (Association, Foundation, Christopher Richards Industry) Industry/Association Program Name, Award Number: USDA-ARS-NCGRP, Ft. Collins CO; [email protected] Washington State Wine Advisory Board Northwest Ag Research Herb Aldwinckle Foundation Federal Program Name, Award Number: ARS CRIS 5358-21000-033-00D Cornell University, Geneva NY; [email protected] Plant explorers have visited Russia, Turkey, Kazakhstan, and China over the past twenty years to find populations of the wild relatives 4:00–4:15 pm of apple (Malus). Seeds from wild populations of M. sieversii, M. PlantCollections—A Tool to Access Data Held by Botanic orientalis, M. hupehensis, M. kansuensis, M. toringo, M. bhutanica, M. transitoria, and M. zhaojiaoensis have been planted at the USDA- Gardens and Arboreta ARS-National Plant Germplasm System (NPGS) Plant Genetic Boyce Tankersley* Resources Unit in Geneva, NY. Malus sieversii and M. orientalis Chicago Botanic Garden, Glencoe IL; [email protected] seedling trees have been screened for disease resistance and evaluated for genetic diversity based on microsatellite markers and ploidies Min Henderson have been identified for the species native to China. Genetic diversity Chicago Botanic Garden, Glencoe IL; [email protected] analyses reveal that most of the overall genetic structure in these David Vieglais species is partitioned among individual families but that significant University of Kansas, Lawrence KS; [email protected] regional differentiation exists. Some accessions exhibit high levels of resistance to apple scab (Venturia inaequalis Cooke), cedar apple Greg Riccardi rust (Gymnosporangium juniperi-virginianae Schwein) as well as Florida State University, Tallahassee FL; [email protected] fire blight (Erwinia amylovora Burrill) and could be very valuable in Christopher Dunn disease resistance breeding programs. Genotypic data for microsatellite University of Hawaii, Honolulu HI; [email protected] markers is publicly available in the new molecular observation tables in the Germplasm Resources Information Network (GRIN) database Pam Allenstein (http://www.ars-grin.gov/npgs/). American Public Gardens Association, Wilmington DE; pallenstein@pub licgardens.org Specified Source(s) of Funding: Federal competitive Federal Program Name, Award Number: This project was partially supported by the PlantCollections—A Community Solution provides access over the National Research Initiative of the USDA Cooperative State Research, WWW to plant records data held in botanic gardens and arboreta. Education and Extension Service, grant number #2005-00751. Eighteen botanic gardens & arboreta participating in the project provide access to records of over 50,000 taxa. Scientists from eight disciplines and plant recorders from the botanic gardens were surveyed 4:30–4:45 pm to determine the 161 fields in the federated schema. These records Domestication and Commercialization of reflect environmental and biological data from collection sites and Taraxacum kok-saghyz, a Potential Domestic Source plant growth, aesthetics, propagation, mortality, and weather data collected in gardens. This project is the first instance of the use of of Natural Rubber and Inulin: Progress and Outlook Google Base as a central WWW repository for biodiversity data. It Ann Chanon has quick responses, caches large volumes of data, is free, and exten- The OSU-OARDC, Wooster OH; [email protected] sively mirrored. The Portal for accessing the data integrates Web2O Daryl Ehrensing advances and can access other data providers using RSS or ATOM. Living plant collections, herbaria, DNA, image, and seed storage Oregon State University, Corvallis OR; [email protected] databases all contribute data. A partnership with Morphbank has A. Raymond Miller provided storage of digital images while Google Map/Earth can be The Ohio State University, Wooster OH; [email protected] used to create distribution maps. Among the benefits to horticultural scientists are the creation of an application that bridges technology, John Streeter nationality, language, professional affiliations, and cost concerns. It The OSU-OARDC, Wooster OH; [email protected]

1136 HORTSCIENCE, VOL. 43(4), JULY 2008 Stephen C. Myers between grapevine and Arabidopsis. The analysis shows that the ARF The OSU, Columbus OH; [email protected] genes from V. vinifera fall into three groups. The group I includes 11 members that contain a conserved N-terminal DNA binding domain Fred Michel (DBD). The seven-member group II is rich in Glu in the middle region The OSU-OARDC, Wooster OH; [email protected] of the proteins. VvARF3 and VvARF4 from the group II, however, Matthew Kleinhenz* have an incomplete DBD. They also lack the non-conserved middle The Ohio State University-OARDC, Wooster OH; [email protected] region and the conserved C-terminal domain, similar to AtARF23. The group III has 4 members, all containing additional 32-36 amino Robert Seiple acid residues within the DBD. In all 45 members of ARF genes from University of Akron, Akron OH; [email protected] Arabidopsis and grapevine, nine sister pairs are identified and each pair shares high identities of amino acid sequence in the conserved The Ohio BioProducts Innovation Center (OBIC) and its private- and regions and possesses similar gene structures. These results suggest public-sector collaborators employ a market-pull approach to accelerate that these nine sister pairs may be orthologous ARFs between Arabi- the commercialization of renewable specialty chemicals, polymers/ dopsis and grapevine. plastics and advanced materials. Taraxacum kok-saghyz (TKS) roots contain high levels of inulin and high quality natural rubber but TKS is Specified Source(s) of Funding: Department, College, State and/or currently undomesticated. Since 2006, a private-public, multi-institu- HATCH tion, multi-disciplinary team has worked to position TKS as a domestic source of natural rubber and inulin. TKS was the focal point of the WWII-era “Emergency Rubber Project” and is now considered a prime 5:00–5:15 pm candidate to complement Hevea brasiliensis as a main source of natural rubber for multiple applications. Also, while native to Uzbekistan and Assessment of Genetic Diversity among Elderberry Kazakstan, TKS is adapted to the mid- and upper latitudes of the U.S. (Sambucus sp.) Species, Cultivars, and Still, TKS is relatively absent in the scientific literature. Beginning in Wild Selections by TRAP Technique Ohio with 39 g (approx. 1500 seed per gram) of wild-collected TKS Hwei-Yiing* seed, the project team has developed protocols to differentiate kok- Johnson Cooperative Research & Extension, Lincoln University Jefferson saghyz from other members of Taraxacum, assessed root rubber and City MO; [email protected] 1st Author inulin levels, and extracted rubber and inulin using commercial-like methods. The team has also allowed unrestricted crosses and performed Patrick Byers controlled crosses among TKS individuals previously testing high for State Fruit Experiment Station, Missouri State University Mountain Grove rubber production potential. And, various properties of TKS-derived MO; [email protected] ORALS–WEDNESDAY rubber have been analyzed. To date in Ohio: a) 6151 TKS seedlings have been generated and another 9000 Taraxacum seedlings await Jinguo Hu roguing; b) root rubber levels of 10% or greater (commercialization Northern Crop Science Research Laboratory, USDA, ARS Fargo ND; threshold) have been found in 145 of 1467 individuals tested; c) average [email protected] root rubber levels have increased from 1.4% to 8.9%; d) root inulin Andrew Thomas levels have averaged 53.4%; e) properties of TKS-derived rubber Southwest Research Center, University of Missouri Mt. Vernon MO; have been similar to those of Hevea-based natural rubber; and f) 73.5 [email protected] g of improved TKS seed have been produced. Follow-up work will integrate improvements in TKS genetics and production, harvesting Samson Tesfaye and rubber/inulin extraction methods. Lincoln University Jefferson City MO; [email protected] Specified Source(s) of Funding: Department, College, State and/or The American elderberry (Sambucus canadensis L.) is a large shrub HATCH Private (Association, Foundation, Industry) OARDC Re- native to much of North America that produces edible flowers and search Enhancement Competitive Grants Program (Seed Competition) fruit. A large collection of elderberry cultivars and selections (pre- OARDC Research Enhancement Competitive Grants Program (New dominantly S. canadensis, but also S. nigra L. and S. pubens Michx.) Enterprise Competition) Ohio Third Frontier, Ohio BioProducts In- has been established in Missouri for evaluation of their commercial novation Center Industry/Association Program Name, Award Number: wine and nutraceutical potential. The genetic relationship among JumpStart, Inc. wild and cultivated elderberry plants, both within and among species, is largely unknown. In this project, a PCR-based target region amplification polymorphism (TRAP) genotyping technique was uti- 4:45–5:00 pm lized to assess the genetic diversity and relationship of 66 elderberry accessions across three species. DNA samples were prepared from Bioinformatic Analysis of Auxin Response Factor (ARF) young leaf tissue for TRAP amplification. In each PCR reaction, one Genes in Grapevine fixed primer was combined with four arbitrary primers labeled with Xia Ye* fluorescent dyes. Two fixed primers used for two PCR reactions in The University of Tennessee Knoxville TN; [email protected] this study were designed against the conserved Arabidopsis thaliana L. telomere-repeat sequence and a sunflower (Helianthus annuus L.) (Max) Z.-M. Cheng* expressed sequence tag (EST). The TRAP amplification results in more The University of Tennessee Knoxville TN; [email protected] Main Author than one thousand polymorphic markers useful for cluster analysis aided by the NTSYSpc software (version 2.2). TRAP markers clearly The plant hormone auxin plays many important roles in plant growth distinguished the three elderberry species, with S. pubens sharing only and development through regulating a variety of genes, such as auxin 23% genetic similarity with the other two species. These markers also response factors (ARFs). ARFs are transcription factors that bind to generally differentiated cultivars and selections from the southeastern TGTCTC auxin response elements in promoters of early auxin re- Canada/northeastern U.S. region compared with selections from the sponse genes and regulate auxin-mediated transcriptional activation midwestern U.S., with some exceptions. Wild plants from Missouri and or suppression. Towards understanding how these ARFs function in Arkansas shared high genetic similarities ranging from 50% to 65%. grapevine, we extracted all 22 ARF genes from the recently completed In addition, results showed a lack of genetic distinction among wild genomic sequence database of grapevine (Vitis vinifera) and compared elderberries collected from within four Missouri ecoregions. This low them with well-characterized Arabidopsis ARFs. A phylogenetic tree spatial genetic variation within Missouri native elderberries suggests was created from alignments of the full-length protein sequences of their potential adaptability to all regions within the State. 22 VvARFs and 23 AtARFs to examine the phylogenetic relationships

HORTSCIENCE, VOL. 43(4), JULY 2008 1137 Specified Source(s) of Funding: Department, College, State and/or is fallow weed control. The purpose of this study was to reduce the HATCH purple nutsedge population using fallow weed control. Field studies were conducted in Live Oak and Citra, Florida, during the fallow periods of 2006 and 2007. Both experiments were arranged in a randomized Oral Session 31: complete-block design with four replications. The Live Oak experiment was a factorial design. The two factors were tillage and herbicides. Culture & Management: Vegetable Crops 2 Tillage treatments had two levels; disking and no disking. Herbicide treatments had three levels; no herbicide, glyphosate at 1.4 kg/ha, and Wednesday 23 July 3:30–5:15 pm Salon 12 glyphosate at 1.4 kg/ha plus halosulfuron at 0.056kg/ha. In Citra, the Moderator: Thomas Bjorkman, [email protected] treatments consisted of an untreated control, a cultivated control, and herbicide treatments of glyphosate at 1.4 kg/ha and paraquat at 0.84 3:30–3:45 pm kg/ha by themselves and in combination with s-metolachlor at 1.34 kg/ha and trifloxysulfuron at 0.01 kg/ha. All herbicides were applied Changes in Onion (Allium cepa) Yield and Grade by a backpack sprayer and mixed with a non-ionic surfactant at 0.25% Distribution in Response to Cover Crop and Plant volume/volume ratio. Each treatment was applied twice each season for Population two consecutive fallow seasons. The plots were permanently marked with metal stakes; therefore, each treatment was applied to the same Mathieu Ngouajio* exact spot every time. In Live Oak, two representative weed counts Michigan State University, East Lansing; [email protected] were taken per plot before and after each treatment. In Citra, purple Darryl D. Warncke nutsedge infestation data was recorded by visually rating the plots. The Michigan State University, East Lansing; [email protected] ratings were the percentage of control compared to the untreated plot; therefore, a rating of 0 = no control and a rating of 100 = total control. James W. Counts, Jr. Disking alone increased nutsedge emergence by the end of the second Michigan State University, East Lansing; [email protected] year of fallowing in Live Oak. Both herbicides significantly reduced Crop rotation and cover crops have been shown to affect onion (Allium nutsedge compared to the untreated control regardless of disking. In cepa) seedling establishment, plant stand, and bulb yield. Final plant Citra, by the end of the first year all treatments resulted in 70% or population may have a profound impact on yield and grade distribu- higher control of purple nutsedge except for paraquat by itself and tion and thus economic value of the crop. Field experiments were the untreated control. After the second fallow season, all treatments conducted in 2007 at Michigan State University Muck Research Farm. resulted in higher nutsedge control (above 52.5%) compared to the The study used two cover crops (and a bare ground control) combined untreated control. with a range of onion densities (172,000 to 290,000 plants/A). The Specified Source(s) of Funding: Department, College, State and/or cover crops were oilseed radish (Raphanus sativus ‘Defender’), and HATCH yellow mustard (Sinapis alba ‘Tilney’). The cover crops were sown on 9 Sept. 2006, and onion the following spring (2007). Yellow mustard improved onion stand establishment (4%) and yield (7%) compared 4:00–4:15 pm with the control. Oilseed radish did not produce adequate biomass due to late planting and consequently did not improve onion yield. All plant Biology and Integrated Management of Corn Chamomile populations used produced comparable total and marketable yields. (Anthemis arvensis) in Processing Peas This indicates that growers could reduce seed cost without affecting Daniel Brainard* yield. Bulb size distribution was the major yield component affected Michigan State University, East Lansing; [email protected] by plant population. As plant population increased, the proportion of small bulbs also increased. This suggests that optimum density for Virender Kumar highest economic value would depend on the selling price for the Cornell University Ithaca NY; [email protected] various grades. Our results suggest that onion growers could offset Robin Bellinder the cost of yellow mustard cover crop seed with a small reduction (about 5%) of their plant population. Also plant population could be Cornell University Ithaca NY; [email protected] used to modify onion grade distribution and ultimately to optimize Christopher Benedict economic value of the crop. Cornell University Ithaca NY; [email protected] Specified Source(s) of Funding: Private (Association, Foundation, Corn chamomile is an important weed contaminant in peas in New Industry) Industry/Association Program Name, Award Number: York, producing flower buds which cannot be easily separated from Michigan Onion Committee peas during processing. Corn chamomile can behave as both a winter or a summer annual, and both fall and spring germinating individuals can be found in pea fields. Field and greenhouse experiments were 3:45–4:00 pm conducted to (i) evaluate the relative importance of overwintering and Fallowing Systems to Control Purple Nutsedge spring germinating cohorts in pea production, (ii) assess seed production and seed characteristics of this species in peas and rotational wheat in Florida Vegetable Crops crops, and (iii) use this information to develop integrated strategies for Theodore McAvoy* management. Overwintering corn chamomile cohorts escaping field University of Florida, Gainesville; tmcavoy@ufl.edu preparation in the spring were found to be most problematic in peas. These overwintering cohorts were difficult to control with herbicides William Stall the following spring both before and after pea planting. A more effective University of Florida, Gainesville; wmstall@ufl.edu strategy appears to be targeting management to prevent establishment Bielinski Santos of fall cohorts. Buckwheat and sorghum-sudangrass cover crops planted University of Florida, Wimauma; bmsantos@ufl.edu in late summer reduced emergence of corn chamomile in the fall in 1 of 2 years. Corn chamomile seed production in rotational wheat crops Gregory MacDonald was found to be a major input to the weed seed bank. Seeds collected University of Florida, Gainesville; pineacre@ufl.edu from corn chamomile in wheat fields ranged in weight from less that With the phase out of methyl bromide, alternatives must be found for 3 mg to more than 15 mg per seed. Small seeds (3 mg) from these weed control in Florida vegetable production. One alternative method plants shed earlier than larger seeds and exhibited less dormancy, with

1138 HORTSCIENCE, VOL. 43(4), JULY 2008 15% to 20% germination of fresh seeds and 40% to 50% germination cated study. Sweet corn (Zea mays) seeds, cultivar ‘Silver Queen’, the following spring. Large seeds were found to be highly dormant, were planted in pots and the vegetative growth was monitored over a contributing to the long-term seed bank. Our results suggest that ef- period of 35 days. Samples of potting medium and compost mixture fective management of corn chamomile involves prevention of seed were analyzed for physical and chemical properties before planting and production in rotational wheat crops, and prevention of establishment after harvest. At harvest, plant height, fresh weight, and leaf area were of fall cohorts through use of cover crops, tillage, or herbicides the measured and leaf tissue was analyzed for nutrient content. Increasing season prior to pea production. the amount of immature compost incorporated in the potting medium resulted in a decrease in plant height, fresh weight, and leaf area. Im- Specified Source(s) of Funding: Federal competitive Northeastern mature compost increased the levels of macro- and micronutrients, IPM Center Partnership Grant ammonium, nitrate, electrical conductivity (EC), and pH values. High ammonium content coupled with alkaline condition favors the formation of ammonia. The potential build up of ammonia could damage the 4:15–4:30 pm root system and adversely affect plant growth. Plant tissue analysis Buckwheat Cover Crops for Vegetable Rotations to indicated no difference in macro-nutrient contents between the con- Reduce Weeds and Improve Soil Condition trol and immature compost treated plants. However, accumulation of micro-nutrients such as copper, iron, and manganese, was detected in Thomas Bjorkman* compost-treated plants. These elevated content of micro-nutrients could Cornell Univ., Geneva NY; [email protected] reach toxic levels and contribute to the stunted growth. Plant height Buckwheat has long been used for weed management and soil im- and soil parameters such as EC, ammonium, and manganese contents provement in the northeast United States. It has value today used as were linearly correlated with the increasing amounts of incorporated a summer cover crop before or after vegetables. Its advantage over immature compost. Testing for ammonium and micro-nutrients is other cover crops at this time is superior weed suppression, and the expensive and requires technical skills. Therefore, measuring plant shortest growing interval (<40d). Investigations were undertaken to height and EC of a growth medium can be simple and cost effective find answers to growers needed to fit it into current cropping systems. techniques to detect immaturity of a compost. The outcome of those trials resulted in a set of recommendations that Specified Source(s) of Funding: Department, College, State and/or are applicable in the northeast and Great Lakes regions. The manage- HATCH ment goals in the recommendations all support the following guidance: Fast start. No gaps. Kill on time. In order to get a fast start, buckwheat needs to be sown into warm soil (about May 20 to Aug. 10 in Western

4:45–5:00 pm ORALS–WEDNESDAY New York). The soil needs to be loosened moderately if following a vegetable; no-till is not effective. Seeds should be placed as shallow Critical Period of Interference between American Black as possible into soil with at least a little moisture. It cannot follow Nightshade and Seedless Watermelon herbicides that have carryover inhibition: atrazine, Pursuit, Reflex, or Joshua Adkins* Sandea. Heavy rainfall with standing water following sowing stunts University of Florida, Gainesville; jia84@ufl.edu growth. Fertilizer is not necessary. In order to avoid gaps, seed should be sown in rows 8 inches apart or less, or broadcast very uniformly William Stall at 50 to 70 lb/ac. Wet and hard spots in the field should be sown to University of Florida, Gainesville; wmstall@ufl.edu something tougher. The crop should be killed on time if volunteer seed Bielinski Santos will create a problem. Usually it does not. The time to kill buckwheat is when it comes into full bloom and the field appears solid white University of Florida, Wimauma; bmsantos@ufl.edu (about 30 to 40 d after sowing). It can be mowed at this time without Stephen Olson regrowth and without seeds maturing. Incorporation allows waiting University of Florida, Quincy; smolson@ufl.edu 5 days longer. By following these guidelines, growers have reported consistent success. Weed suppression has been effective and soil Jason Ferrell condition has improved. University of Florida, Gainesville; jferrell@ufl.edu Specified Source(s) of Funding: Federal competitive Private (Associa- Studies were conducted to determine the critical period of interference tion, Foundation, Industry) NE-SARE, NY Farm Viability Institute between American black nightshade (Solanum americanum Mill.) and triploid (seedless) watermelon (Citrullus lanatus L.) grown on polyethylene-mulched beds. Trials were located at the Plant Science 4:30–4:45 pm Research and Education Unit in Citra, FL, (PSREU) and the North Florida Research and Education Center in Live Oak, FL (NFREC). A Greenhouse Study of Immature Compost Effects on In Spring 2007, American black nightshade was established at 0, 1, 2, Plant and Soil Properties 3, 4, and 5 weeks after watermelon transplanting and remained until Rufus Jones watermelon harvest (plant back study) or was established at watermelon Cooperative Research & Extension, Lincoln University Jefferson City transplanting and removed at 0, 1, 2, 3, 4, and 5 weeks after planting MO; [email protected] (removal study). There was no significant interaction between locations and treatments concerning marketable yield. Therefore, marketable Hwei-Yiing* yield data (marketable fruit number) was combined from PSREU Johnson Cooperative Research & Extension, Lincoln University Jefferson and NFREC. Regression analysis was conducted to test the effect of City MO; [email protected] treatment on data expressed as percentage of weed-free control. The regression model for the plant back study was exponential with an R2 Yichang Sun value of 0.92. For the removal study, the regression model was linear Plant and Soil Testing Laboratory, University of Missouri Columbia MO; with an R2 value of 0.86. The models were used to predict the mini- [email protected] mum weed-free period and the maximum period of competition for a This study demonstrates effects of immature compost on plant growth 10% yield loss. The minimum weed-free period and maximum period and identifies plant and soil properties that are sensitive to improperly of competition was predicted to be 3.3 and 5.2 weeks, respectively. composted materials. Lincoln University (LU) cafeteria food waste Therefore, in order to avoid watermelon yield loss greater than 10%, composted for one month, instead of the routine three months, was nightshade establishment should be delayed for at least 3.3 weeks incorporated into potting medium at 30%, 60%, and 90% in a repli- after transplanting or nightshade removal should take place by 5.2 weeks after transplanting.

HORTSCIENCE, VOL. 43(4), JULY 2008 1139 Specified Source(s) of Funding: Private (Association, Foundation, Nadav Ravid Industry) Paramount Farming Company Bakersfield CA; [email protected] Hazel Wetzstein* University of Georgia, Athens GA; [email protected] 5:00–5:15 pm Improving Tuber Yield of Native Potatoes in the Peruvian Flowering in pomegranate, Punica granatum, is characterized by hav- Highlands by Using Local Affordable ing two flower types: 1) hermaphroditic flowers with both male and female parts, and 2) functionally male flowers which produce pollen, Calcium Amendments but generally fail to set fruit. This condition, andromonoecy, allows Jiwan Palta* a species to optimize the allocation of limited resources to male and University of Wisconsin–Madison; [email protected] female function. However, under production conditions, high numbers of male flowers can result in decreased yields. To better understand Rene Gomez developmental differences in the flower types, morphological and International Potato Center, Lima 12, Peru [email protected] histological evaluations were made of hermaphroditic and male Alfonso del Rio flowers of the Wonderful cultivar collected from Paramount Farming University of Wisconsin–Madison; [email protected] Company orchards. Flowers were evaluated using light and scanning electron microscopy. Hermaphroditic flowers had a discoid stigma with William Roca elongated papillae, a single elongated style, and numerous stamens International Potato Center, Lima 12, Peru; [email protected] inserted on the inner wall of the calyx tube. Ovules were elliptical John Bamberg and numerous. Male flowers had numerous well formed stamens, but female structures were underdeveloped. Pistils were reduced to varying University of Wisconsin–Madison; [email protected] degrees. However, stigmas had well developed papillae that supported Alberto Salas pollen germination. Ovules in male flowers were rudimentary and International Potato Center, Lima 12, Peru; [email protected] exhibited various stages of degeneration. Merideth Bonierbale Specified Source(s) of Funding: Department, College, State and/or International Potato Center, Lima 12, Peru; [email protected] HATCH Private (Association, Foundation, Industry) Previous research conducted at the University of Wisconsin has demonstrated that in season calcium fertilization can improve tuber 3:45–4:00 pm quality of several U.S. cultivars including chipping, russet, and red Floral Initiation and Development in Pomegranate potatoes. In addition, calcium application has been shown to reduce the adverse effects of environmental stresses. However, no studies Hazel Wetzstein* have been conducted on the response of native potatoes grown in the University of Georgia Athens GA; [email protected] Andean highlands. Many locations in the Andes tend to be acidic, and Nadav Ravid thus are low in available calcium. The present study was initiated to Paramount Farming Company, Bakersfield CA; [email protected] determine the response of native potatoes to calcium nutrition. For this purpose, the experiment was conducted at San Jose de Aymara Although pomegranate, Punica granatum , has been cultivated since (potato farming community near Huancayo, Junin, Peru; approximate ancient times, there are limited reports on the reproductive biology of elevation 4,000 m.). For this purpose, 20 landraces and 5 cultivars were this crop. In this study, temporal and spatial evaluations of flower induc- planted in Dec. 2005. Locally available gypsum was used as a source tion and development were conducted using trees grown in commercial of calcium and was incorporated into the soil at planting. Treatments orchards (Paramount Farming Company, Bakersfield, CA). Shoots of were replicated three times. At harvest, all tubers were removed by the Wonderful cultivar were collected at different times from January hand and weighed. Overall results showed that calcium application (when shoots were dormant) until mid-May (when shoots were rapidly tended to increase yield in nearly all the materials tested; however, elongating). The shoot apices of terminal and lateral buds/shoots were this increase was not statistically significant in every case. There was dissected and evaluated using light and scanning electron microscopy. a significant increase in yield in 7 landraces and 3 cultivars. The tuber In dormant buds, the shoot apex remained vegetative with no flower yields of cultivars Mariva and Perricholi increased by 30% and 40%, primordia observed. Bud development was complex. With the onset respectively as compared to control. The increase in yield by calcium of bud break, the precocious initiation of axillary buds was evident. treatment was 20% to 50% for the native potatoes. Possible influence Reproductive development was not observed until early shoot expan- of calcium treatment on nutritive value is being investigated. These sion. Floral initiation was noted at the shoot apex and in axillary buds results are very encouraging and suggest that local amendments can subtended by young developing leaf primordia forming clusters of be used in the highlands to improve the yield of native potatoes. flowers at the terminal portions of expanding shoots. Flower initiation in pomegranate does not occur during the previous season, but on new Specified Source(s) of Funding: Department, College, State and/or growth with numerous flowers induced in terminal and lateral buds. HATCH Stages of flower organogenesis and development were determined and will be described. Specified Source(s) of Funding: Department, College, State and/or Oral Session 32: Fruit Crops 3 - Culture and Management HATCH Private (Association, Foundation, Industry) Wednesday 23 July 3:30–5:15 pm Salon 8 Moderator: Chandra Putcha, [email protected] 4:00–4:15 pm Effect of Foliarly-applied Acids and Ferrous Sulfate 3:30–3:45 pm on Leaf Ferrous Iron Content and Leaf Greeness of Morphological and Histological Evaluations of Flower Avocado Trees Types in Pomegranate Jonathan Crane* Adriana Pinheiro Martinelli Univ. of Fla., IFAS, TREC Homestead FL; jhcr@ufl.edu Universidade de Sao Paulo Piracicaba, SP, Brazil; [email protected] Bruce Schaffer University of Florida Homestead FL; bas56@ufl.edu

1140 HORTSCIENCE, VOL. 43(4), JULY 2008 Yuncong Li index (RI), nonsignificant differences were observed. Maximum oil Univ. of Fla., IFAS, TREC, Homestead FL; yunli@ufl.edu was recovered from Brazilian Sour Orange (BSO) and proved to be superior among all other rootstocks. So far there is no utilization of Edward Evans Kinnow peel and it is a biomass waste from juice industry of Pakistan. Univ. of Fla., IFAS, TREC, Homestead FL; eaevans@ufl.edu Thus, it could be taken as an enterprise to best utilize the biomass and Wanda Montas a lot of revenue can be generated from oil of Kinnow peel. Univ. of Fla., IFAS, TREC, Homestead FL; wmontas@ufl.edu Specified Source(s) of Funding: Department, College, State and/or Li Chungfang HATCH Univ. of Fla., IFAS, TREC, Homestead FL; chunfang@ufl.edu

Iron deficiency is a major nutritional problem of avocado trees (Persea 4:30–4:45 pm americana Mill.) grown in calcareous soils. Applications of chelated iron to calcareous soil are efficacious, but very expensive. The ef- Fruit Growth of Four Pomegranate Cultivars from fects of foliarly applied organic acids and organic acids plus ferrous Northern Oman sulphate (FS) and an organosilicone adjuvant (Freeway) on iron Rashid Al-Yahyai* nutrition of 10-year-old cv. Donnie avocado trees in calcareous soil Sultan Qaboos University Al-Khoud, Oman; [email protected] was investigated during 2006 and 2007 in southern Florida. At 13-23 day intervals, trees received the following foliar treatments: ascorbic Fahad Al-Said acid (AA alone), ascorbic acid and FS (AA+Fe), citric acid and FS Sultan Qaboos University Al-Khoud, Oman; [email protected] (CA+Fe), and sulphuric acid and FS (SA+Fe). Additional treatments Linus Opara were chelated iron (EDDHA) applied to the soil 3 times at a 27-28 Sultan Qaboos University Al-Khoud, Oman; [email protected] day interval in 2006 and a 17-42 day interval in 2007, and a control receiving no iron or acid (Control). In 2006, leaf chlorophyll index Pomegranate (Punica granatum L.) is the main and most valuable values determined with a SPAD meter were consistently higher for fruit crop of northern mountainous region of Oman. Pomegranates trees in the EDDHA treatment than trees in all other treatments. On are cultivated utilizing traditional farming methods including the two measurement dates, trees in the SA+Fe and AA+Fe treatments had determination of harvest dates, harvesting and postharvest handling. higher SPAD values than trees in the Control and AA alone treatments. Fruit of four native pomegranate cultivars (Hamedh, Malasi, Helow, In 2007, CA+Fe, AA+Fe, and SA+Fe treatments were consistently and Qusum; literally translated as sour, smooth, sweet, and hard- higher than EDDHA, AA alone, and Control treatments. Total leaf iron seeded, respectively) were tagged and monitored for three months content was higher for the SA+Fe, CA+Fe, and AA+Fe (2007 only) up to commercial harvest. Fruit growth length (L) and diameter (D) ORALS–WEDNESDAY treatments than the EDDHA, Control, and AA alone treatments. There were measured at weekly intervals starting from 66 days after the first was no difference in total leaf iron content between the CA+Fe and flush of full bloom until harvest (136 DAFB). During the time course AA+Fe treatments in 2006 and EDDHA and any acid+Fe treatments of fruit growth and development, significant changes occurred in fruit in 2007. Leaf ferrous iron (Fe2+) content was generally higher for shape (L/D) in two cultivars (Malasi and Hamedh) but not Helow and trees in all acid+Fe treatments than the EDDHA, AA alone, or Control Qusum cultivars which also had larger fruit size at harvest. Fruit from treatments after 5-6 foliar acid applications and 3 EDDHA applica- cultivars which have smaller size at harvest (Hamedh and Malasi) had tions to the soil. Economic analysis indicated that foliar applications higher growth rate. The lack of obvious changes in fruit shape during of acid with ferrous sulphate were 63% to 81% less costly than soil growth and development of Qusum and Helow pomegranate cultivars applications of EDDHA. indicates that the attainment of characteristic fruit shape may not be a good indicator of their maturity for harvest management. Thus, fruit Specified Source(s) of Funding: Federal competitive USDA T- harvesting based solely on size and shape is not sufficient and other STAR physico-chemical fruit attributes should be taken into account when assessing readiness to harvest to ensure optimum income returns to growers. 4:15–4:30 pm Recovery and Characterization of Specified Source(s) of Funding: Department, College, State and/or HATCH Peel Oil of Kinnow Mandarin Grafted on Various Rootstocks Waqar Ahmed* 4:45–5:00 pm University of Agriculture, Faisalabad, Pakistan; [email protected] Prediction of Output Parameters Based on Average Muhammad Azher Pruning Weight in Subtropical Fruits Nawaz Agriculture Extension, Lodhran, Pakistan; [email protected] Chandrasekhar Putcha* Raheel Anwar California State University, Fullerton CA; [email protected] University of Agriculture, Faisalabad, Pakistan; [email protected] Radhakrishnamurty Putcha Muhammad Mumtaz Acharya N.G. Ranga Agriculture University Hyderabad; Khan University of Agriculture, Faisalabad, Pakistan; [email protected] [email protected] Sreenivas Rao Muhammad Maqbool Acharya N.G. Ranga Agriculture University, Hyderabad; Sargodha University, Pakistan Sargodha, Pakistan; [email protected] [email protected] The study was conducted to check the effect of rootstocks on recovery of G. Ram Reddy peel oil of Kinnow mandarin (Citrus reticulata Blanco) grafted on nine Acharya N.G. Ranga Agriculture University, Hyderabad; rootstocks: Citrumello-4475, Citrumello-1452, Volkamariana, Yuma [email protected] Citrange, Rough Lemon, Mithi, Troyer Citrange, Carrizo Citrange, and D. Vijaya Brazilian Sour Orange. The results showed significant differences for Acharya N.G. Ranga Agriculture University Hyderabad; peel oil contents, peel moisture percentage, crude fat percentage, crude [email protected] , fiber percentage, and crude protein percentage, while for refractive

HORTSCIENCE, VOL. 43(4), JULY 2008 1141 The work reported herein deals with a methodology to predict output parameters in subtropical fruits based on input param- Oral Session 33: eters for subtropical fruit (grape). The results obtained are based on Commercial Horticulture/Industry/International collaborative research work. The output parameters considered are: average yield (kg/vine), average juice, average TSS (sweetness), and Wednesday 23 July 3:30–5:30 pm Salon 6 average acidity of germplasm. The input parameter considered is the Moderator: Fred T. Davies, [email protected] average pruning weight of grape tree. The key parameter in this study was found to be the average pruning weight, which has maximum effect on the yield of grape, based on the actual field data collected. 3:30–3:45 pm The main aim of the study is to develop a functional relation between Opportunities for Industry, the Public, and the Profession average yield and the key input parameter (average pruning weight of of Horticulture with the ASHS-Certified Horticulturist grape), based on principles of regression analysis. The well-known MATLAB has been used for statistical analysis. The following (ASHS-CH) Program regression equations were obtained for the four output parameters Fred T. Davies* [average yield (y), average juice (j), average TSS, and average acid- Texas A&M University, College Station TX; [email protected] ity (a)] as a function of input parameter of average pruning weight (p). y = -.2851 p + 4.2501; j = 1.1834 p + 61.69; tss = -0.047 p + Mary Lamberts 19.6028; a = -0.0804 p + 0.8245 MATLAB has been successfully UF Miami-Dade County Extension, Homestead FL; lamberts@ufl.edu used to develop a functional relation between the various output pa- George Fitzpatrick rameters related to grape (average yield, average juice, average TSS, University of Florida, Fort Lauderdale; fitz@ufl.edu and average acidity) as a function of the input parameter of average pruning weight. The results should be useful for both academic and Terry Ferriss research communities. University of Wisconsin–River Falls; [email protected] Specified Source(s) of Funding: Department, College, State and/or Susan Steinberg HATCH University of Houston, Houston TX; [email protected] Karen Panter University of Wyoming, Laramie; [email protected] Janet Cole 5:00–5:15 pm Oklahoma State University, Stillwater; [email protected] Effect of Fruit Thinning on the Ray Talke Quantitative and Qualitative Characteristics Minds in Action, Inc., Uxbridge MA; [email protected] of Date Palm cv. Aseel Mike Neff Ghulam Sarwar ASHS Headquarters, Alexandria, VA; [email protected] Markhand Shah Abdul Latif University, Khairpur, Sindh, Pakistan Khair- pur FL; [email protected] How does ASHS stay relevant in the current climate of decreased funding and support for horticulture at the University level, and increased Abdul Razak competition, consolidation, and globalization in all segments of the Mahar Shah Abdul Latif University, Khairpur, Sindh, Pakistan Khairpur horticultural industry? The ASHS-Certified Horticulturist (ASHS-CH) FL; [email protected] program is being developed to enhance the professional image of the Adel A. Abul-Soad discipline and industry of horticulture and the professional standing of Hort. Res,. Institute, ARC, Egypt practicing horticulturists by validating the horticultural competency of working horticultural practitioners who have at least 3-years of paid Naseem Akhtar experience in a horticultural profession, and may or may not have a Hort. Res,. Institute, ARC, Egypt 4-year college degree in Horticulture or a closely related field. The ASHS-CH Program is designed to certify industry and individual Manual fruit thinning of date palm (Phoenix dactylifera L.) on horticulture practitioners both inside and outside ASHS core con- the quantitative and qualitative characteristics of one of the best stituencies. This outreach has the potential to attract new members varieties in Pakistan and the world, ‘Aseel’, was carried out. Uni- to ASHS while making it more relevant to the public and to industry. form trees were selected and leaf : bunch ratio of 7 : 1 was imposed. In 2006, ASHS approved the development of the ASHS-CH program Sixteen different combinations of possible manual thinning were and hired Minds in Action Inc., a professional certification develop- performed. Number of bunches, no. of spikes and the spike’s length ment service. Development of the ASHS-CH Program began with were reduced manually after six weeks of pollination. Results indicated a Job Task Analysis Workshop in which participants from industry, that thinning increased significantly the quantitative properties. extension, and academia initially identified 57 discrete tasks needed Where the average fruit yield was 152 Kg/tree when number of for an ASHS-CH to safely and effectively perform job functions. bunches reduced to 19 bunches with removal of the central forth There was a national survey (of industry participants from the 26 spikes number. As well as, the qualitative properties of the fruits types of organizations employing potential applicants for certifica- increased significantly. The average fruit weight increased from tion) to identify the 35 most important tasks. Results of the survey 10.9 g/fruit in control treatment (no spikes removal) to 13.1 g/fruit. were compiled into a Certification Test Blueprint to guide creation of Also, fruit thinning significantly increased the fruit diameter, flesh the certification exam and professional educational offerings in the weight and didn’t effect on total sugar, reducing, non-reducing, and areas identified. Participants from industry, extension and academia pH of fruits. attended a Test Item-Writing Workshop, followed by two Technical Specified Source(s) of Funding: Department, College, State and/or Review Workshops to vet questions. In 2008 a certification exam was HATCH Date Palm Research Institute Project funded by Higher assembled, and initial development of study materials, marketing Education Commission, Islamabad, Pakistan and promotion, fee structures, and administration began. The first certification exam is to be given at the July 2008 ASHS meeting in Orlando. Help is needed in marketing, promotion, working on exams, proctoring, and serving the ASHS-CH committee.

1142 HORTSCIENCE, VOL. 43(4), JULY 2008 3:45–4:00 pm AVRDC–The World Vegetable Center has initiated a research and Farmer Participatory Evaluation of Affordable development program to improve organic vegetable production in the tropics. The Organic Vegetable Program is located at the center’s Microirrigation Technology for Vegetable Production in headquarters in the tropical southwest of Taiwan. Major program Cambodia goals are: 1) to reduce farmers’reliance on pesticides and 2) to open Manuel Palada* new income opportunities for resource-poor farmers. A six-hectare AVRDC–The World Vegetable Center Shanhua, Tainan, Taiwan; field has been managed organically for more than three years, adher- [email protected] ing to the Production Standards for Organic Agricultural Products - Crops of Taiwan. An agroforestry plot of about one hectare for the Surya Bhattarai intercropping of vegetables with tropical fruit trees also has been Central Queensland University Queensland, Australia; [email protected] established. About 30 different vegetable species have been grown Michael Roberts organically for demonstration and research. We assessed yield and IDE Cambodia Phnom Penh, Cambodia [email protected] fruit quality, soil fertility management, and the economic benefits of including vegetables in agroforestry systems. We also conducted Low-cost drip irrigation (LCDI) can be an affordable means of expand- evaluations of selected cultivars under organic farming conditions. ing irrigation into rainfed areas, thereby increasing land productivity. Several field crops were included in the program to gain experience This study determined the performance of LCDI as evaluated by for future whole-farm research and development, as many farmers vegetable farmers in Cambodia. The study also evaluated the effects in developing countries also raise rice, sweet potato, and sweet corn NPK fertilizer briquette compared to conventional compound fertil- in addition to vegetables. Initial findings indicate high-input organic izer with LCDI and hand watering (HW) in two vegetable crops on vegetable production methods achieved yields and qualities compa- yield and water use efficiency (WUE). Yield and WUE increased rable with conventional farming systems. Under conditions of high significantly with LCDI compared to HW on cucumber (13% and biotic and abiotic stress, low-input organic vegetable production 41%), sponge gourd (85% and 129%), eggplant (38% and 113%) and did not achieve similar benchmarks. However, low-input organic bitter gourd (121% and 35%), but low response on long bean (5% and vegetable production has significant value for identifying superior 27%, respectively). In general, the average yield increased by 34% and germplasm that can be adapted to produce under various stress condi- WUE increased by 76% with LCDI. Marketable yield and water use tions. Knowledge generated from these studies will serve as a base efficiency of cucumber increased (22% to 25%) with NPK briquette for collaborative research and development projects with AVRDC’s deep placement compared to conventional NPK fertilizer irrespective regional and international partners. of irrigation treatments, whereas in long bean it increased only by 9% Specified Source(s) of Funding: Private (Association, Foundation, for both yield and WUE. Net increase in income due to briquette was ORALS–WEDNESDAY greater by 24% and 14% on cucumber and long bean, respectively, Industry) compared to compound fertilizer. The effect of irrigation methods on man days employed for irrigation was almost six times greater in HW compared to LCDI, although no significant effect was noted on weeding and spraying operations. The average net return with LCDI 4:15–4:30 pm was greater by 52% compared to HW and varied from 4% to 121% between the crops. These results suggest that LCDI and NPK briquettes Factors Influencing the Growth of can significantly improve yield, WUE and profitability of vegetable Farmers Markets in Indiana crops under farmers’ management conditions. Both technologies are Jennifer Dennis* feasible options toward increasing vegetable production and profit- Purdue University West, Lafayette IN; [email protected] ability for small-scale farming in Cambodia during the dry season when irrigation water is limited. Christa Hofmann University of Kentucky, Henderson KY; [email protected] Specified Source(s) of Funding: Private (Association, Foundation, Industry) Industry/Association Program Name, Award Number: Maria Marshall AVRDC-IDE Federal Program Name, Award Number: CG Challenge Purdue University, West Lafayette IN; [email protected] Program for Water and Food Nationally, the number of operating farmers’ markets has increased 111% in the past ten years from 1,755 markets to 3,706 from 1994 to 2004 (amS, 2006). Indiana’s farmers’ markets have increased at 4:00–4:15 pm double the rate in the same time frame. An internet and mail cen- Development of an Organic Vegetable Program at sus was sent to market masters to assess operational procedures, AVRDC–The World Vegetable Center factors that influence customer and vendor participation, and factors that influence a relationship with their local health department at the Peter Juroszek market. A two-stage least squares model was estimated for the ven- AVRDC—The World Vegetable Center Shanhua, Tainan, Taiwan; dor and customer models and an ordered probit model was used for [email protected] the local health department model. Our model shows vendors who Manuel Palada* pay fees and the number of customers present at the market were AVRDC—The World Vegetable Center Shanhua, Tainan, Taiwan; the two variables that had a significant, positive influence on vendor [email protected] participation. The presence of WIC, number of products available, the absence or presence of live music, absence or presence of cooking Chin-Hua Ma demonstrations, and vendors were significant for the customer model AVRDC—The World Vegetable Center Shanhua, Tainan, Taiwan; at the 0.01 level. The absence or presence of concession stands and [email protected] picnic areas were significant at the 0.10 level in the customer model. Hsing-Hua Tsai Market organizers who used cooking demonstrations at their markets AVRDC—The World Vegetable Center Shanhua, Tainan, Taiwan; ida. were more likely to have a strong relationship with the local health [email protected] department. Deng-Llin Wu Specified Source(s) of Funding: Department, College, State and/or AVRDC—The World Vegetable Center Shanhua, Tainan, Taiwan; HATCH [email protected]

HORTSCIENCE, VOL. 43(4), JULY 2008 1143 4:30–4:45 pm preferred sources of information. Growers were also asked to respond Defining Horticultural Businesses in Wyoming to questions pertaining to their understanding of research objectives and their perceived role in the development of these objectives. Of Karen Panter* the growers surveyed, 35% felt that they knew what the primary re- University of Wyoming, Laramie; [email protected] search objectives were in berry research programs and 45% expressed In Summer 2006, 889 surveys were mailed out to green industry satisfaction with the amount of input they had on the development businesses in Wyoming. The mailing consisted of a one-page cover of research objectives. Over 70% of growers are optimistic about the letter, the survey, and a self-addressed, stamped envelope for return- future of the berry industry in New York State. Information gathered ing the completed survey. In early August 2006, reminder postcards from this study can be used to improve the efficacy of extension were sent to those who had not yet returned their surveys. Of the 889 programs and to develop creative ways to facilitate dialogue between surveys sent, 202 were returned with usable information, a return rate researchers and growers. of 23%. Responses indicated people are in horticultural businesses in Specified Source(s) of Funding: Department, College, State and/or Wyoming mostly to make a profit but also enjoy working with plants HATCH Private (Association, Foundation, Industry) New York Farm and like a challenge. They are moderately sensitive to environmental Viability Institute issues. The majority relies on trade magazines, trade organizations, or peer/support groups for information. Most prefer information in print form, followed by newsletters, workshops/meetings/field days, 5:00–5:15 pm and the internet. Most respondents use municipal or well water. Roughly half have current pesticide applicator licenses, and very New York State Greenhouse IPM and Needs Assessment few are involved in niche, natural products, or other specialty type Surveys of horticulture. Horticultural businesses in Wyoming run the gamut Neil Mattson from interior plantscaping, to landscape design and maintenance, to Cornell University, Ithaca NY; [email protected] greenhouses, and florist shops, as well as public sector entities such as cemeteries, parks, and municipal golf courses. Most operations Elizabeth Lamb are either sole proprietorships or public enterprises. Many would not Cornell University, Ithaca NY; [email protected] divulge their incomes, but of those who did, 14 earned more than $500K in 2005. The total value of respondents businesses in 2005 According to the USDA Floriculture Crops 2006 Summary, New was between $14,964,500 (low end of range) and $23,619,391 (high York State had 721 greenhouse floriculture production operations, end of range). Businesses have an average of 9.4 paid employees and with over 26,000,000 square feet of greenhouse space and with an the majority is in business year-round. Marketing is heavily retail and estimated wholesale value of $207 million. Two surveys were recently service-based. Demographically, the group is heavily male and most conducted with commercial growers and retailers. The objective are 45 years or older. The overwhelming majority is Caucasian and of the first survey was to evaluate the current use and the level of well over half have at least a 2-year college degree. Their enterprises adoption of IPM practices. Questions covered important crops and have been in operation an average of about 24 years. pests, cultural practices related to IPM, scouting, disease/weed/insect management, and sources of IPM information. The survey was mailed Specified Source(s) of Funding: Department, College, State and/or to 900 growers and a 44% response rate was realized. The majority HATCH Private (Association, Foundation, Industry) Wyoming Com- of respondents use preseason sanitation practices. Analyis of pH and munity Forestry Council Industry/Association Program Name, Award nutrient levels in water, growing media, or foliage is not a common Number: Wyoming Groundskeepers and Growers Association practice. Scouting is widely accepted as an IPM practice and most growers incorporate some additional elements of IPM in their pest management. The objective of the second survey was to determine 4:45–5:00 pm production practices, information sources, and barriers to success and profitability faced by commercial greenhouses. The survey was Communication and Relations between Small Fruit distributed at grower training workshops, during on-site visits, and Growers and Research Institutions in New York State as an on-line survey advertised in newsletters. In terms of business Rebecca Harbut* operations, the majority of respondents identified energy, labor, Cornell University, Ithaca NY; [email protected] and hard good costs as challenges. The ability to attract and retain competent employees and weather uncertainty were also commonly Marvin Pritts cited difficulties. Primary challenges for growing high quality crops Cornell University, Ithaca NY; [email protected] included insect and disease control, management of the greenhouse Arthur Wilson growing environment, crop irrigation, and fertilizer use. Few respon- Cornell University, Ithaca NY; [email protected] dents currently market their products as sustainable/organic, though many expect to do so in the future. The survey results are being used Since the early 1900s, researchers at Experiment Stations and Agricul- to focus applied research and outreach efforts to areas where both the tural Colleges have conducted research geared to improving agricultural need and potential for impact exist. production. The transfer of information from researchers to growers has primarily been facilitated by extension agents whose role is to act Specified Source(s) of Funding: Department, College, State and/or as liaison between growers and researchers. This communication has HATCH I have a special request for my abstract submission. I will been accomplished in several ways including; bulletins, newsletters, only be able to be at the conference on 23 July and 24. I would ap- publications, farm visits, and field days. While several of these forms preciate it if you could schedule the presentation/poster presentation of communication have been utilized for decades, the availability of to take place on one of those two days. internet access has led to additional forms of communication as well as access to seemingly infinite amounts of information. The objective of this study was to determine the forms of communication and sources 5:15–5:30 pm of information currently used by berry growers in New York State and Initiation of the Northern EarthKind™ Rose Trial to evaluate the relationship between growers and researchers. Surveys David C. Zlesak* were sent via postal service or e-mail to berry growers across the state and interviews were conducted with a subset of growers. Data col- University of Minnesota, Andover MN; [email protected] lected included; demographics, production practices, marketing, and Jason Griffin Kansas State University, Haysville KS; jgriffi[email protected]

1144 HORTSCIENCE, VOL. 43(4), JULY 2008 Derald Harp were studied in relation to bud fruitfulness. For Experiment 1, 100 Texas A&M University, Commerce TX; [email protected] head-trained vines were spur-pruned and 10 shoots were allowed to grow per vine. When the shoots were 15 nodes long, the subtending Kathleen Cue spur was girdled and all leaves removed. The 10-node shoot section University of Nebraska, Lincoln; [email protected] growing subsequently was either left intact or defoliated on one or Nick Howell both sides. In shoots defoliated on one side, the buds were shaded Iowa State University, Ames; [email protected] on the defoliated or on the foliated side, or were left uncovered. In Experiment 2, shoots were defoliated as above and the leaves were Tamla Blunt either shaded or left uncovered. In Experiment 3, the shoots were Colorado State University. Fort Collins; [email protected] defoliated as above and the subtending spur girdled or left intact. An Randy Nelson additional 15 nodes were allowed to grow beyond the 10-node section but were defoliated regularly. The 10-node sections were then University of Minnesota. Moorhead; [email protected] removed and the buds were assessed for fruitfulness and analyzed for Steven George total non-structural carbohydrates (TNCs). Defoliation significantly Texas A&M University Dallas TX; [email protected] reduced fruitfulness and bud TNCs and the effect remained strongly confined to the defoliated side. Leaf shading had the same effect on The EarthKind™ program, started at Texas A&M, provides growers, fruitfulness as defoliation. When shoots were defoliated or shaded on landscapers, and consumers with research-based recommendations one side, fruitfulness on the defoliated or shaded side was 40% to 70% supporting environmental stewardship of the ornamental landscape. lower than the foliated or exposed side. The correlations of fruitful- One component of EarthKind™ is the evaluation and selection of ness to bud TNCs suggest a direct role of carbohydrates during early superior cultivars through regional cultivar trials. Roses have been differentiation of inflorescence primordia in grapevines. Regulation the flagship crop under the EarthKind™ program. Prior to planting of flowering by bud carbohydrate content seems very sensitive since in a randomized complete-block design, 7.6 cm (3 in.) of compost is fruitfulness went from zero to 100% when TNCs increased by a factor incorporated into the native soil. Following planting, beds are mulched of 0.3 or slightly less. with 7.6-10.1 cm (3-4 in.) of organic mulch. Plants are irrigated during the establishment phase and no pesticides or additional fertilizers Specified Source(s) of Funding: Department, College, State and/or are used. Performance data are taken monthly during the growing HATCH season in years two through four following planting. To date, seventeen highly adapted cultivars have received EarthKind™ designation for the southern U.S. region. There is a need to identify EarthKind? 8:15–8:30 am worthy roses in other regions. The Northern EarthKind™ Rose Trial Effect of Training System on Grapevine Vigor, Yield, and was initiated in 2007 to identify adapted landscape roses with suitable cold hardiness for USDA zones 3-5. Twenty cultivars were selected for Fruit Composition in the Lower Midwestern U.S. inclusion in the trial based on recommendations from green industry John Strang professionals and rosarians: Alexander Mackenzie, Brite Eyes, Care- University of Kentucky, Lexington; [email protected] free Beauty, Frontenac, George Vancouver, John Cabot, John Davis, Lena, Morden Blush, Ole, Polar Joy, Prairie Joy, Quadra, Ramblin’ Chris Smigell Red, Seafoam, Summer Wind, Sunrise Sunset, Sven, William Baffin, University of Kentucky, Lexington; [email protected] and Yellow Submarine. Trial sites were planted in 2007 in Minnesota, S. Kaan* Kansas, and Texas. Kansas and Texas were added to ascertain cultivar Kurtural University of Kentucky, Lexington; [email protected] performance in warmer regions for possible inclusion in future trials in those regions. Additional sites are planned to be planted in Nebraska, Effects of vertical shoot positioned (VSP) and fan-trained (Fn) systems Iowa, Colorado, and Minnesota in 2008. Performance data on this were evaluated on five commercially important wine grape cultivars cultivar group will be complete in 2011 with the potential of the first in a completely crossed experiment, in a mature vineyard for two Northern EarthKind™ winning roses announced in 2012. growing seasons. The grapevines were planted at a density of 965 vines/ha. All grapevines were dormant pruned to 16 shoots per meter ORALS–THURSDAY Specified Source(s) of Funding: Department, College, State and/or of row and cluster thinned to 60-70 clusters per vine. There was very HATCH Minnesota Agricultural Experiment Station Industry/Associa- little interaction of training system and cultivar on vine vigor. The tion Program Name, Award Number: Bailey Nurseries, Chamblee’s fan-trained grapevines had 64% and 22% of the non-count shoots Rose Nursery, Greenheart Farms, and Sam Kedem Nursery removed in years 1 and 2, respectively. The Fn-system grapevines had 18% and 10% more marketable clusters than the VSP-system grapevines in years 1 and 2, respectively. Yield was not affected by the training system in either year. ‘Vidal blanc’ out-yielded all cultivars Oral Session 34: Viticulture and Small Fruits/Physiology in both years of the study by 55%, except for ‘Cabernet franc’ in year Thursday, 24 July 8:00–10:00 am Salon 8 1. Cluster weights were not affected by the interaction of training system and cultivar in either year. The interaction of training system Moderator: Kevin Kosola, [email protected] and cultivar affected percent total soluble solids (TSS) and titratable acidity (TA) in ‘Shiraz’ and ‘Vidal blanc’. The VSP- system Vidal 8:00–8:15 am blanc had higher TSS compared to ‘Shiraz’, and Fn-system Shiraz had Bud Carbohydrate Status and Fruitfulness the highest TA compared to all other cultivars. Berry weight was 3%, and 5% higher in the VSP-system grapevines compared to Fn-system of Vitis vinifera L. in years 1 and 2, respectively. The Fn- system in the lower Midwest Luis Sanchez* produces a higher number of marketable clusters per vine, however it E&J Gallo Winery, Modesto CA; [email protected] has higher operating costs due to extensive non-count shoot removal for canopy management, and lower fruit composition values, and is Nick Dokoozlian thus not recommended for commercial vineyards >0.5ha in size. E&J Gallo Winery, Modesto CA; [email protected] Specified Source(s) of Funding: Private (Association, Foundation, Bud carbohydrate content in girdled Vitis vinifera L. cv. Thompson Industry) Industry/Association Program Name, Award Number: Seedless shoots was manipulated in three experiments through de- Kentucky Grape and Wine Council foliation and leaf or bud shading and the effects of the treatments

HORTSCIENCE, VOL. 43(4), JULY 2008 1145 8:30–8:45 am top three performers, 101-14, 3309, and 420A and in 2004 each of Nutrient Response of ‘Pinot Noir’ in a Sand-culture these rootstocks again bore fruit which had significantly lower TA, but also significantly higher °Brix and pH than self rooted. Observed yield Vineyard was also higher in 2004 for plants grafted on the three rootstocks, due R. Paul Schreiner* mainly to higher incidence of early bud stem necrosis (EBSN) on self USDA-ARS-HCRL Corvallis OR; [email protected] rooted plants. In 2005-2007 data consistently showed lower fruit TA levels on all three of the grafted rootstocks compared to self rooted Jungmin Lee plants. Over the six-year period of this study, these three rootstocks USDA-ARS_HCRL Parma ID; [email protected] resulted in lower acids, which translates into earlier maturity (10-14 Nitrogen, phosphorus and potassium supply to grapevines (Vitis days) on the scion cultivar Pinot Noir 2A. Preliminary comparisons vinifera, cv. Pinot noir) grown in sand were each manipulated to bet- using 101-14 and 3309 rootstock on other cultivars indicates a similar ter understand how nutrients influence the growth, physiology and effect of lower fruit TAs and thus earlier maturation over self rooted fruit quality attributes of this winegrape variety. In 2006 and 2007, vines. four rates of N, four rates of P, or four rates of K were supplied to Specified Source(s) of Funding: Private (Association, Foundation, vines with other plant nutrients held constant. Effects on vine growth Industry) Industry/Association Program Name, Award Number: (shoot length, leaf area) were not significant in either year, but vines Washington State Wine Advisory Board Northwest Ag Research receiving low N had lower N concentrations in leaves and petioles Foundation and lower SPAD readings in both years. Low N vines also had lower K concentrations in petioles and higher P concentrations in petioles in 2007. P and K treatments did not alter P and K status in 2006, but did so in 2007. Effects of nutrient treatments on leaf gas exchange, 9:00–9:15 am chlorophyll fluorescence, leaf water potential, or soil moisture were Light Quality Affects Flowering in Short-day generally not significant in either year. High levels of inflorescence ‘Strawberry Festival’ Strawberry necrosis occurred in both years, although it was exceptionally vari- Fumiomi Takeda* able from vine to vine. The incidence of flower necrosis was lower in those vines receiving less N in 2006, but this did not occur in 2007. USDA-ARS, Kearneysville WV; [email protected] Fruit was dropped from all vines in 2006 to minimize potential ef- David Michael Glenn fects of crop load differences on subsequent growth and physiology USDA-ARS, Kearneysville WV; [email protected] of these vines. Since nutrient treatments did not affect flower necrosis in 2007, fruit clusters were retained and carried to maturity. N, P, or Gary Stutte K treatments did not effect fruit yield, cluster weight, or berry size. Dynamac Corporation, Kennedy Space Center FL; [email protected] Juice soluble solids, titratable acids, and pH were also unaffected by The effect of red light (600-700 nm) directed at the crowns of ‘Straw- nutrient treatments in 2007. However, juice P concentrations were berry Festival’ strawberry transplants maintained under long-day lower in vines receiving less P, and juice P was correlated to leaf and photoperiod in August on flower bud induction was investigated. petiole P. Juice K was lower in both low N and low K vines, but juice When the July-plugged transplants were retained in tray flats at high K was correlated to N status of vines (SPAD & leaf/petiole N). Effects plant density during July and August the leaves developed high leaf of nutrient treatments on other fruit quality parameters, including area index above the plant crowns and the crown near the base of leaf nitrogen, will be discussed. petioles was completely shaded. Wavelengths less than 700 nm did Specified Source(s) of Funding: Department, College, State and/or not reach the crown because the leaves absorbed the photosyntheti- HATCH cally active radiation incident on the leaf surface. Illuminating the crown for 16 h/day for 4 weeks in August with red light decreased transplants that flowered by mid October. The results suggest that the 8:45–9:00 am absence of red light on the crown has a quantitative effect on flower bud induction in ‘Strawberry Festival’ strawberry transplants under Effect of Certain Grape Rootstocks on Harvest Indices in non-photo inductive conditions. Pinot Noir Grape Clone 2A Specified Source(s) of Funding: Private (Association, Founda- Gary Moulton* tion, Industry) -Department, College, State and/or HATCH Project Washington State University, Mt Vernon WA; [email protected], GREEEN Industry/Association Program Name, Award Number: Carol Miles MNLA MCTA Washington State University, Mt Vernon WA; [email protected]

In a maritime climate with low growing degree days (GDD), a major 9:15–9:30 am factor in determining fruit maturity is the level of titratable acid (TA). In 2000, a trial was begun to test the effect of seven grape rootstocks Strawberry Light Sensors and Their Integration grafted on Pinot Noir 2A (Wadenswil clone). Rootstocks were Milllardet into the Photoperiod Pathway et de Grasset 101-14 and 420A, Couderc 3309, Kober 5BB, Malegue Mithu Chatterjee* 44-53, Riparia Gloire, and Teleki 5C. Control was self rooted plants. University of Florida, Gainesville; [email protected] Plots each contained five plants and were replicated five times. The location was three miles from Puget Sound in western Washington, Philip Stewart with average 1693 GDD during the six harvest years. In 2002, GDD University of Florida Gainevsille FL; [email protected] were low at 1527, went up to 1945 in 2003, and declined thereafter. Kevin Folta* Juice analysis at harvest began in 2002 and initially showed that Pinot University of Florida, Gainesville; [email protected]fl.edu Noir 2A grafted on all rootstocks had significantly lower TA than self rooted plants. In 2003, only plants grafted on 101-14, 3309, and 420A Light regulates many events during plant growth and development, showed significantly lower TA than self rooted plants. Plants on 5BB many of which directly affect horticultural traits and production. The and 5C were lower but not significant at the 5% level, while Riparia goal of this work is to identify the set of light sensors in strawberry Gloire and 44-53 were intermediate. In 2003-4 plants on rootstocks (Fragaria sp.) and test their integration with the pathways that regulate 5BB, 5C, and Riparia Gloire were eliminated. Focus was given to the plant morphology, physiology and reproductive habits (particularly flowering). These processes have been elegantly dissected in model

1146 HORTSCIENCE, VOL. 43(4), JULY 2008 systems using physiological, molecular and biochemical techniques. 9:45–10:00 am In this study, we translate the findings from model systems to the dip- Use of Gibberellic Acid to Inhibit Flower Bud Formation loid and cultivated strawberry. This study presents identification and characterization of components related to the photoperiodic flowering in Newly Established Blueberries pathway, including the phytochrome, cryptochrome, and phototropin Chrislyn Particka* light sensors. Their effects are demonstrated in transgenic plants. The Sakuma Bros., Inc., Burlington WA; [email protected] structure and function of the CONSTANS (CO) gene is described. Brent Black Fragaria CO is a single copy gene per haploid genome with multiple, differentially-expressed alleles, and has been assigned to Group VI of Utah State University, Logan UT; [email protected] the Fragaria linkage map. Overexpression of the Fragaria CO restores Recent studies indicate that early cropping in northern highbush normal flowering habits to the Arabidopsis co mutant, and contributes blueberries (Vaccinium corymbosum L.) adversely impacts vegetative to an uncharacteristic long hypocotyl phenotype in developing seed- growth, plant establishment, and subsequent yields. There are currently lings. Expression analyses indicate that unlike other plants, Fragaria no efficient methods for regulating early cropping in blueberries. We CO transcripts peak only at dawn on short days. Expression patterns recently reported that late summer foliar applications of GA3 (ProGibb) are similar in octoploid and diploid accessions, in both short-day and and GA4+7 (ProVide) (Valent BioSciences) could effectively reduce day-neutral cultivars. Limited accumulation is observed under long flower bud number in young potted plants of ‘Bluecrop’ and ‘Duke’. day conditions in all genotypes tested. This report provides an initial The present study evaluated foliar applications of these formulations characterization of the input side of the photoperiodic flowering applied to field-grown ‘Liberty’ blueberry plants at 400 mg·L-1 active pathway and how light signals are integrated to control the flowering ingredient concentration. Treatments compared application timings transition in strawberry. from 30 Aug. 2006 through 25 Oct 2006, at weekly intervals. Floral Specified Source(s) of Funding: Department, College, State and/or and vegetative buds were counted and yield data were collected the HATCH following spring and summer. The GA products were equally effective and there was a linear relationship between application date and response with the earliest treatments most effectively reducing flower bud number (53% reduction), estimated fruit number (41% reduc- 9:30–9:45 am tion), and yield (24% reduction). The reduced crop load resulted in ITS-PCR Characterization of Ericoid Mycorrhizal significantly larger fruit in the remaining crop. This study indicates Fungal Communities in Cultivated Cranberry from the that foliar applications of commercial GA formulations can effectively Field and in Trap-culture reduce flowering and fruiting in the field, and may be an effective tool in blueberry crop load management, both for reducing precocity and Kevin Kosola* optimizing fruit size. University of Wisconsin, Madison Chesterfield MO; [email protected] Specified Source(s) of Funding: Private (Association, Foundation, Karsten Holmquist Industry) USDA-ARS, Madison WI; [email protected] Beth Ann Workmaster University of Wisconsin–Madison; [email protected] Oral Session 35: Cranberry (Vaccinium macrocarpon) is typically colonized by ericoid Postharvest Physiology/Disorders/Handling and Quality mycorrhizal fungi both in cultivation and in its native habitat. Fungal communities can be characterized by PCR amplification of the internal Thursday, 24 July 8:00–10:00 am Salon 7 transcribed spacer of fungal ribosomal DNA using the primers ITS1F and ITS4. We have characterized the ericoid mycorrhizal fungal com- Moderator: Kevin Folta, kfolta@ufl.edu munity in roots of cranberry collected from both wild and cultivated populations in Wisconsin. Cultivated plant samples were collected from 8:00–8:15 am ORALS–THURSDAY seven different farms from a wide range of bed ages and 8 different cultivars. Based on cloning of PCR products, fungal communities on GABA Changes in Tomatoes in Response to Chilling cultivated cranberry roots contained multiple cultured (especially Rhi- Temperature zoscyphus ericae) and uncultured fungal species, but were dominated Rujira Deewatthanawong* by uncultured fungal species. We have evidence of mycorrhizal fungal Cornell University, Ithaca NY; [email protected] transfer in solution culture from a live inoculum cranberry plant to surface-sterilized recipient cuttings (trap culture); fungi transferred Chris Watkins included Sebacina types previously found in salal (Gaultheria shallon) Cornell University, Ithaca NY; [email protected] in British Columbia. After approximately eight weeks of exposure in The relationship between gamma aminobutyric acid (GABA), a non solution culture, individual recipient plants each contained subsets of protein amino acid shown to be involved in the biotic and abiotic stress the terminal restriction fragment length (T-RFLP) patterns found in responses in plants, and chilling stress of cold stored tomatoes has the host plants, and in one out of eight cases a single recipient plant been investigated. Tomato fruit of 68 introgression lines of a popula- contained only a single T-RFLP ribotype. Control surface-sterilized tion of Lycopersicon pennellii in the background of L. esculentum cuttings grown during this same period in hydroponic containers were screened for chilling sensitivity. Fruit were stored at 3 °C for 3 without inoculum plants were free of mycorrhizal colonization. Trap weeks and incidences of surface pitting and decay determined after culture methods should allow isolation and characterization of the removal to 20 °C. Lines 3-4 and 7-4-1 were found to be the most function of uncultured mycorrhizal fungi in cranberry. sensitive to chilling stress, while lines 2-6 and 11-2 were the most Specified Source(s) of Funding: Department, College, State and/or chilling tolerant lines. GABA response in those four lines with dif- HATCH Private (Association, Foundation, Industry) USDA-CSREES ferent sensitivity to chilling stress was investigated in the following University of Wisconsin Hatch 142-E778 Industry/Association Program year. Higher chilling sensitivity of the introgression lines was related to Name, Award Number: Wisconsin Cranberry Board Robert and Helen higher amounts of GABA in cold stored fruit. Reduced concentrations Gottschalk Endowment of GABA in cold stored fruit were observed in more tolerant lines. GABA concentrations declined after removal of the fruit to 20 °C in all lines. Glutamate decarboxylase (GAD) and GABA transaminase (GABA-T) activities of fruit of sensitive lines were similar to those

HORTSCIENCE, VOL. 43(4), JULY 2008 1147 of untreated fruit, while tolerant lines had lower GAD activities and Muhammad Nafees higher GABA-T activities. Differences in GABA pattern in chilled The Islamia University Bahawalpur, Pakistan; nafeescaes@googlemail. tomato fruits suggests that there is a relationship between the GABA com shunt and chilling sensitivity. Saeed Ahmad Specified Source(s) of Funding: Department, College, State and/or University of Agriculture, Faisalabad, Pakistan; sandhu100hasan@yahoo. HATCH Federal competitive USDA-ARS Specific Coop. Agree- com ment 58-6402-4-026 with CRIS MIS-223010. Specific project: Field Establishment of Medicinal Herbs and Potential for Commercial Ishtiaq Ahmad Bahauddin Production” Zakariya University, Multan, Pakistan; [email protected] Storage life of mango fruit is considered to be low enough than required for export through sea freight as air freight is a costly transportation 8:15–8:30 am method for mango industry of many developing countries, including Incidence of Chilling Injury in Fresh-cut ‘Kent’ Mangoes Pakistan. This experiment was conducted with a view to subject fruit to higher temperature before storage which would extend their storage Sharon Dea* life. Healthy, mature, and hard green mango fruit cv. Samar Bahisht University of Florida, Gainesville; shdea@ufl.edu Chaunsa were harvested from a commercial orchard and subjected to Jeffrey K. Brecht high-temperature treatment at 36 °C, 38 °C, or 40 °C for 24 or 48 hours University of Florida, Gainesville; jkbrecht@ufl.edu and kept at 9 °C, 13 °C, and 15 °C until fruit reached eatable ripening stage with respect to skin color and/or fruit softness. Severe skin dis- Maria Cecilia N. Nunes coloration was observed in fruit that were subjected to storage at 15 °C University of Florida, Gainesville; nunes@ufl.edu without high-temperature treatment while this disorder decreased with Elizabeth A. Baldwin increase in conditioning temperature. Early fruit softness was observed in fruit conditioned and stored at higher temperature. Total carotenoids, USDA–ARS Winter Haven, FL; [email protected] TSS, and sugar contents increased while total titrable acidity decreased The preferred storage temperature for fresh-cut fruits in terms of with increase in conditioning temperature and storage temperature. visual quality retention is around 5 °C, which is considered to be a High-temperature treatment of fruit at 40 °C for 24 hours and further chilling temperature for chilling sensitive tropical fruits like mango storage at 9 °C exhibited maximum storage life i.e. 25 days. Moreover, (Mangifera indica L.). Changes in visual and compositional quality chilling injury symptoms were also less produced in same treatment factors, aroma volatile production, respiration rate, and electrolyte as compared with control. High-temperature treatment of fruit at 40 leakage were evaluated in whole and fresh cut ‘Kent’ mangoes stored °C for 48 hours further increased fresh fruit weight loss (11.5%) and for 10 days at chilling (5 °C) and non-chilling (12 °C) temperatures. skin shriveling. Overall, results revealed the efficacy of pre-storage The experiment was repeated twice during two Florida mango seasons high-temperature treatment to increase storage life and inhibiting from two different sources; tissue firmness was measured in the second chilling injury in mango fruit cv. Samar Bahisht Chaunsa. experiment only. Whole fruit (control) were stored along with the Specified Source(s) of Funding: Department, College, State and/or fresh-cut mango slices and processed as such on the days of analysis. HATCH Soluble solids content and aroma volatile production (based on the quantification of 16 aroma volatiles) did not differ among whole fruit and fresh-cut slices stored at chilling or non-chilling temperatures for both experiments, with the exception of ethanol, which was higher 8:45–9:00 am in whole fruit and slices stored at 12 °C. Visual quality degradation Shelf Life and Quality of “Ready-to-Eat” Edamame was faster at 12 °C than at 5 °C, limiting the shelf life to between 3 Douglas Archbold* and 4 days at 12 °C vs. 5 to 6 days at 5 °C. The respiration rate, pH, University of Kentucky, Lexington KY; [email protected] and total ascorbic acid were highe r in the fruit stored at 12 °C, while titrable acidity was higher at 5 °C. Electrolyte leakage was higher in Xiaodan Zhao fresh-cut slices than in whole fruit, but no conclusion could be made University of Kentucky, Lexington KY; [email protected] as to the effect of storage temperature. It is unclear whether the storage period at 5 °C was sufficiently long to cause chilling (CI) in fresh-cut Chlodys Johnstone mango slices since no visual CI symptoms developed in whole fruit. University of Kentucky, Lexington KY; [email protected] However, reduced ascorbic acid content and increased softening at 5 ‘Ready-to-eat’ edamame may have potential as a healthy snack food. °C suggest that the fresh-cut slices did experience chilling stress. For this to occur, the edamame could be blanched in the pod, frozen Specified Source(s) of Funding: Federal competitive USDA TSTAR for storage and shipping, and thawed prior to purchase. This study examined the effects of a delay before blanching and of post-thawing shelf life duration on pod and seed quality traits, including pod color, and seed content of soluble sugars, phenolics, ascorbic acid, and total 8:30–8:45 am antioxidant activity, of 11 edamame cultivars. Following harvest or Assessment of Storage Life and Ripening Quality after a 3-day delay while held at 4 °C, pods were blanched, frozen in of Mango Fruit after Pre-storage High-temperature sealed poly bags at -20 °C, then thawed and held in 4 °C storage for Treatment 0, 3, 7, and 14 days. Pods became lighter in color if blanching was delayed for 3 days and as a result of blanching, but not while in cold Raheel Anwar* storage. Pods became less green when blanching was delayed for 3 University of Agriculture, Faisalabad, Pakistan; [email protected] days and was lower at each sampling date while in cold storage. A Muhammad Khawar Nadeem couple of cultivars exhibited some blackening by 14 days. Sucrose University of Agriculture, Faisalabad, Pakistan; [email protected] was the major sugar present, at 10x the level of glucose. Sucrose content declined 10% through 7 days of cold storage, and another Waqar Ahmed 9% from 7 to 14 days. Glucose content nearly doubled from 0 to 7 University of Agriculture, Faisalabad Faisalabad, Pakistan days but changed little thereafter. Total amino acid content declined [email protected] at each sampling date. Total antioxidant activity, phenolic content, Muhammad Aslam Pervez and ascorbic acid content declined 20-30% as a result of blanching and from 0 to 3 days of cold storage, but levels of these traits did not University of Agriculture, Faisalabad, Pakistan; [email protected]

1148 HORTSCIENCE, VOL. 43(4), JULY 2008 change due to the delay in blanching or from 3 to 14 days of cold stor- mg·L-1 BA or 5, 10, or 25 mg·L-1 BA+GA4+7. A non-sprayed control age. The impact of these changes on marketability of “ready-to-eat” was maintained. Plants were grown in the same environment until edamame will be discussed. marketable and then were placed in a growth chamber at 15 °C in darkness for 2 or 4 d to simulate shipping. Subsequently, plants were Specified Source(s) of Funding: Department, College, State and/or placed in a growth chamber at 20 °C under a 12-h photoperiod (~50 HATCH mol·m-2·s-1 PPF) for 4 weeks, spaced so their leaves were touching, to simulate a retail environment. Numbers of deteriorated leaves (chlorotic, necrotic, or abscised) were recorded 2 and 4 weeks after 9:00–9:15 am initiation of storage. Irrespective of the application time or shipping ‘Camarosa’ Strawberry Postharvest Quality is Affected duration, BA+GA4+7 did not influence the number of deteriorated leaves by Hot Water, Salicylic Acid and Calcium Dipping at the rates tested after 2 or 4 weeks of storage of miniature rose and gerbera daisy. In geranium, BA sprays had no effect on the number Toktam Sadat* of deteriorated leaves after storage for 2 or 4 weeks. However, when Taghavi University of Tehran, Karaj FL Iran [email protected] geranium was sprayed with BA+GA4+7 at 2.5, 5, and 10 mg·L-1 at the Maaedeh Shafiee visible bud stage, the mean number of deteriorated leaves decreased University of Tehran, Karaj FL Iran maaedeh_shafi[email protected] by 30%, 82%, and 93% after storage for 2 weeks and 9%, 46%, and 28% after storage for 4 weeks, respectively, compared with the non- Mesbah Babalar sprayed control. In addition, the mean number of deteriorated leaves University of Tehran, Karaj FL Iran [email protected] on geranium sprayed with BA+GA4+7 at first open flower decreased by 152%, 91%, and 116% after storage for 2 weeks and 104%, 45%, Kevin Folta and 70% after storage for 4 weeks, respectively, compared with the University of Florida, Gainesville; [email protected]fl.edu non-sprayed control. This experiment was conducted to study the effects of three different Specified Source(s) of Funding: Department, College, State and/or postharvest treatments and their combinations on keeping quality of HATCH Private (Association, Foundation, Industry) strawberry (Fragaria ananassa Duch. cv. Camarosa) during storage. Postharvest heat treatment has been used for insect disinfestations and disease control, modification of fruit responses to different stresses, and maintaining fruit quality during storage. Application of salicylic 9:30–9:45 am acid (SA), a phenolic antioxidant compound, has been studied as an Effects of Foliar Calcium Application on Peach Fruit alternative to chemicals to maintain the quality and reduce decay of Quality and Yield strawberry fruits. Postharvest application of calcium also prevents Kathryn Taylor* postharvest disorders, retards fruit ripening and decreases postharvest decay. This experiment was a randomized complete-block design University of Georgia Byron GA; [email protected] (RCBD) with two factors (treatments) and three replications. Posthar- Calcium is essential for plant cell function and plant tissue integrity. vest treatments were in eight levels [25 °C water, 45 °C water, 25 °C Its physiological activity as a second messenger and its requirement in & 45 °C water containing CaCl2 (1%), 25 °C & 45 °C water contain- cell wall structure make it important to fruit growth and development, ing salicylic acid (2 mM) and 25 °C & 45 °C water containing CaCl2 fruit quality, the rate of fruit senescence, and abiotic and biotic stress (1%) and salicylic acid (2 mM)]. Fruits were divided in 3 groups and resistance. This is an intermediate report of the impacts of several quality characteristics of the first group were evaluated immediately calcium formulations applied throughout peach fruit development and after harvest. Quality characteristics of the other two groups were growth. These studies were initiated to assess the effect of Ca(NO3)2, evaluated 7 & 14 days after treatments at 2 °C. Heat treatment, SA CaCl2 and Calcium Metalosate on fruit firmness and shelf life. All and Ca dipping decreased decay, chroma (brightness) and a* (red of the formulations tested improved fruit quality, by reducing fruit color development) in comparison with control. SA and calcium cracking and post harvest fruit rots relative to the untreated control, dipping decreased weight loss and increased firmness. Hot water and with the exception of an excessively high level of Calcium Metalosate

SA dipping increased hue angle (less browning). The combination of ORALS–THURSDAY . Among the treatments, CaCl2 gave the best impact on reduction for the three postharvest treatments improved characteristics like firm- peel cracking and fruit rots. However, an unexpected effect was noted ness and vitamin °C and decreased decay and weight loss. Therefore, with the Calcium Metalosate of increasing fruit yield via an increase adding SA to hot water or Ca solution acted like the combination of in fruit size, i.e., the proportion of fruit that was in the size category three treatments in maintaining strawberry fruit quality and can be ® of 2.75 inches and larger was not different for Nutrical and CaCl2, recommended for commercial use in this cultivar. but it was higher for the Calcium Metalosate® fruit. Data concerning the impact of formulation nitrogen content on fruit quality will also be presented. We noted that increasing nitrogen content was negatively 9:15–9:30 am correlated with fruit quality with comparison of the high rate of Calcium ® -1 -1 The Influence of Benzyladenine Alone or with Gibberellic Metalosate ; at 16 m·L relative to the labeled rate of 2.5 m·L . Acid on Inhibition of Postharvest Leaf Chlorosis of Specified Source(s) of Funding: Private (Association, Foundation, In- Potted Geranium, Miniature Rose, and Gerbera Daisy dustry) Industry/Association Program Name, Award Number: Georgia Agricultural Commodity Commission for Peaches Sonali Padhye* Michigan State University, East Lansing; [email protected] Erik Runkle 9:45–10:00 am Michigan State University, East Lansing; [email protected] Optimum Harvest Maturity for Extended We quantified the influence of benzyadenine (BA) alone or with gib- Postharvest Quality of Melting and Non-melting berellic acid (GA4+7) on the inhibition of postharvest leaf chlorosis Flesh Subtropical Peach Varieties and necrosis of potted geranium (Pelargonium ‘Pinto Red’), miniature Ming-Wei Kao* rose (Rosa ‘Alicante’) and gerbera daisy (Gerbera ‘Festival Dark Eye Orange’). Young plants were grown in a glass greenhouse set at University of Florida, Gainesville; kaoming@ufl.edu 20 °C under a 16-h photoperiod. At visible bud or first open flower, Jeffery G. Williamson -1 4+7 geranium was sprayed with 2.5, 5, or 10 mg·L BA or BA+GA and University of Florida, Gainesville; jgrw@ufl.edu miniature rose and gerbera daisy were sprayed with 25, 50, or 100

HORTSCIENCE, VOL. 43(4), JULY 2008 1149 Jeffrey K. Brecht greenhouse (PRC)]. Random amplified polymorphic DNA (RAPD) University of Florida, Gainesville; jkbrecht@ufl.edu - and simple sequence repeat (SSR)-based genetic distances (GD) among and between parents (5) and their hybrids (6) were calculated Peach fruit can be categorized as melting flesh (MF) and non-melting and compared to phenotype. These germplasms were evaluated for flesh (NMF). The latter fruit remain firmer during ripening, and thus, lateral branch number (LBN), days to 50% flower (DF), fruit number have longer potential shelf life and can be harvested at more advanced and weight per plant, and fruit length (L): diameter (D) ratio. General maturity. Little is known about potential differences in physiological combining ability was significant for all characters, except for L:D in and biochemical changes during fruit ripening and softening for MF all locations, and LBN and DF in the plastic greenhouse environment. and NMF peaches grown in subtropical regions. Thus, there is limited Both market types were discriminatory, and provided similar assess- information on determining optimum harvest maturity and possible ments of relationships among parents and hybrids. Although dramatic differences in postharvest behavior for those peaches. To identify the performance differences were detected between parents and among optimum harvest maturity of subtropical peaches, two MF cultivars, F1 hybrid progeny, a strong relationship between GD and heterotic ‘Tropic Beauty’ and ‘Florida Prince’, and two NMF cultivars, ‘UF Sun’ effects was not detected. and ‘Gulfking’, were harvested randomly when the ground color break (GCB) had occurred on 50%, 70%, and 90% of 100 tagged fruit. Each Specified Source(s) of Funding: Department, College, State and/or 50-fruit sample was classified according to the ground color and fruit HATCH This experiment was supported by National Natural Science diameter, assuming that the sampled peaches accurately represented Funding of China, by Program for Innovative Research Team of North- the maturity distribution in the true population; destructive analyses east Agricultural University, by International Cooperative Funding of of fruit firmness and flesh color were conducted at harvest on 10- Science and Technology Department in Heilongjiang Province, and by fruit subsamples. The remaining fruit were divided into two groups funding of Education Department in Heilongjiang Province. of 20 fruit for two storage experiments. The first group was ripened at 20 °C for 7 days (S1) and the second group was stored at 0 °C for 14 days, and then ripened at 20 °C for 7 days (S2). Ripened fruit were 8:15–8:30 am analyzed for peel ground color and blush color, flesh color, firmness, Inheritance and interaction of Flesh Color Genes Among soluble solids, and titratable acidity. In general, extensive softening in MF peaches in both storage experiments resulted in minimal shelf Canary Yellow, Pale Yellow, and Red Watermelon life for all three harvests. The NMF peaches maintained higher flesh Haejeen Bang* firmness and had longer shelf life than MF fruit in both storage ex- Texas A&M University, College Station TX; [email protected] periments. ‘UF Sun’ fruit harvested at 50% or 70% GCB had greater firmness than fruit harvested at 90% GCB after S1, but not after S2. Sunggil Kim ‘Gulfking’fruit harvested at different percentage of GCB did not show Chonnam National University, Gwangju, South Korea; [email protected] obvious differences in firmness for either storage experiment. The Daniel Leskovar results suggest that harvesting at a more advanced maturity is possible Texas AgriLife Research, Vegetable & Fruit Improvement Center, Texas with NMF peaches, but may be cultivar dependent. A&M System, Uvalde TX; [email protected] Specified Source(s) of Funding: Department, College, State and/or Stephen King HATCH TSTAR Texas AgriLife Research, Texas A&M University, College Station TX; [email protected] There are two genes, canary yellow (c) and inhibitor of canary yellow Oral Session 36: (i-C), reported to control watermelon flesh color between canary yellow and red. Recently, we proposed LCYB as a color determining gene Breeding, Genetics and Germplasm: Vegetable Crops 2 for c locus. We also developed a co-domimant CAPS marker from an Thursday, 24 July 8:00–10:00 am Salon 6 identified critical SNP to distinguish between the canary yellow and red alleles. However, the inhibitory effect of i-C was not detected in Moderator: Kevin Crosby, [email protected] any of our original populations, suggesting that only a single gene was involved in flesh color determination. None of our original populations 8:00–8:15 am contained ‘Sweet Princess’, which was the reported source for i-C. We crossed ‘Yellow Doll’ (canary yellow) with ‘Sweet Princess’ (red) Performance of Melon Hybrids Derived from and selfed the F1 to create a segregating F2 population and included Parents of Diverse Geographic Origin backcrosses to both parents. Over two hundred individual plants were Feishi Luan* genotyped using the CAPS marker. As had been previously reported, Horticulture College Harbin, China; [email protected] canary yellow was dominant to red in this new population. However, a new and distinct color phenotype (pale yellow) was observed in Yunyan Sheng our new population that segregated with CAPS marker for canary Horticulture College Harbin, China; [email protected] yellow flesh. The genetics of this pale yellow phenotype fit a model Yuhan Wang for a single recessive gene influenced by the presence of c. As in our original populations, the inhibitory gene action of i-C was not identi- Agriculture Bureau Penglai, China; [email protected] fied; however, we did notice a low frequency of mixed flesh colors, Jack Staub suggesting that a modifier gene may be influencing the expression University of Wisconsin-Madison Madison WI; [email protected] pattern of c. Most of these mixed flesh colors were characterized by being either mostly canary yellow with streaks of red or pinkish Genetic relatedness and phenotype are important factors that govern red. There were a few phenotypes which were mostly red with minor the expression of heterosis in hybrid progeny. Since this relationship streaks of yellow, but these were always associated with poor fruit is not well understood in melon (Cucumis melo L.), three monoecious development and are not considered to be influenced by modifier genes. and andromonoecious melon lines of diverse Chinese [Peoples Republic These results suggest that i-C does not inhibit the c gene, since our of China (PRC)] origin were crossed to the andromonoecious U.S. marker for the c gene has matched flesh color (either yellow or red) Western Shipping market type Top Mark ™ and the andromonoe- in over 400 PCR tests, but there are modifier genes that influence the cious, highly branched TM derived line H16 to determine parental expression patterns for c. combining ability and heterosis for five yield component traits in three test environments [open-field (USA), and energy-saving and plastic Specified Source(s) of Funding: Federal competitive Designing Foods For Health, USDA CSREES #2006-34402-17121

1150 HORTSCIENCE, VOL. 43(4), JULY 2008 8:30–8:45 am popping time of at least 90 seconds resulted in popping percentages Combining Rust Resistance and Heat Tolerance greater than 90%. in Snap Beans Speciﬁed Source(s) of Funding: Private (Association, Foundation, Charles Wasonga* Industry) Cornell University Geneva NY; [email protected]

Phillip Griffiths 9:00–9:15 am Cornell University Geneva NY; [email protected] Low Temperature Tolerance on Pepper Marcial Pastor-Corrales (Capsicum annum) USDA-ARS Beltsville MD; [email protected] Davut Keles* Tim Porch Alata Horticultural Research Institute Erdemli-MERSIN, Turkey; USDA-ARS Tropical Agriculture Research Station Mayaguez PR; Timo- [email protected] [email protected] Saadet Buyukalaca The production of snap bean (Phaseolus vulgaris L.) is restricted in Cukurova University Adana, Turkey; [email protected] high temperature environments where pods fail to set due to heat stress at flowering. Snap bean production regions that experience heat stress Low temperature tolerance is crucial for off-season protected pepper are also frequently exposed to bean rust caused by Uromyces appendicu- cultivation under Mediterranean region. The objective of this study was latus Pers.:Pers. (Unger). Selection of lines combining these traits could to determine the tolerance of pepper genotypes to low temperatures. improve the yield potential in these areas, and expand the production A total of 1607 genotypes, resulted from six generations of selfing, regions and length of the growing season. Snap bean breeding lines were grown in an unheated greenhouse where plants were protected that are able to set under higher temperatures were selected and used against the frost during the first year of the study. The best performing to develop populations for the introgression of bean rust resistance 562 of the lines grown under sub-obtimal temperatures were selected. genes Ur-4 and Ur-11. Heat-tolerant snap bean breeding lines HT601, The selected genotypes were grown in both heated (minimum night HT603, HT608, and HT611 developed from previous diallel studies temperature is >10 °C) and greenhouses (minimum night temperature that combined heat-tolerant lines were crossed with two rust resistant is >1 °C) in order to measure the level of low temperature tolerance. snap bean breeding lines from USDA-Beltsville (BelJersey-RR-15 and Plant growth rate, number of branches and buds, dates of flowering BelFla-RR1-4) containing the Ur-4 and Ur-11 rust resistance genes. and fruit set, and number of fruits were recorded. The data collected for each line were evaluated using the weighted rankit method. The The hybrids were advanced to the F2 generation and 14 populations were evaluated for yield components under high temperature condi- genotypes were then ranked from the most tolerant to the least tolerant tions (32 °C/27 °C day/night with 14-hour photoperiod) in a controlled according to their rank scores. The 30 genotypes (10 most tolerant, 10 greenhouse environment with heat sensitive and heat tolerant controls. A medium tolerant and 10 least tolerant) were selected for the growth total of 75 selections from the 14 populations were made and re-tested chamber studies. The selected genotypes were kept for 7 days in the flowering period in a growth chamber that was kept at 2 °C and 26 under high temperature stress conditions at the F3 generation. The lines were simultaneously evaluated for bean rust genes Ur-11 and Ur-4 °C during night and day, respectively. The mature flower buds of the through inoculations at USDA-Beltsville, and DNA was isolated from genotypes were removed before placing into the growth chamber. After low temperature treatment, pollens were collected and pollen the F3 plants in the heat trial and tested with SCAR markers for the Ur-11 and Ur-4 genes. Selections combining rust resistant genes and germination test was performed using agar in petri method. When the pollen germination results and the weighted rank scores were tolerance to high temperatures will be tested under high temperature 2 field conditions in Juana Diaz, Puerto Rico, in Summer 2008. Selec- compared, a moderately high correlation (R = 0,74) was observed tions are being crossed to snap bean varieties common in East Africa, between two measurements. Therefore, pollen germination test can be where field trials of materials will be undertaken in 2009. used as morphological marker to determine low temperature tolerance of pepper genotypes. Results of both greenhouse and growth room

Specified Source(s) of Funding: Department, College, State and/or experiments showed that the most tolerant pepper genotype is Alata ORALS–THURSDAY HATCH Cornell Assistantship for Horticulture in Africa (CAHA) 111 and the most susceptible one is Alata 195. Specified Source(s) of Funding: Federal competitive 8:45–9:00 am Environmental Effects on Nuña Bean Popping 9:15–9:30 am James Nienhuis* Characterization of Novel Traits and Cultivar University of Wisconsin, Madison WI; [email protected] Development in Habanero-type Peppers (Capsicum Jesse Vorwald chinense Jacq.) University of Wisconsin, Madison WI; [email protected] Kevin Crosby* Nuña beans are a type of common bean (Phaseolus vulgaris L.) na- Texas A&M University Weslaco TX; [email protected] tive to the Andean region of South America that possess the unusual Daniel Leskovar property of popping; however, little is known about the environmental Texas AgriLife Research, Vegetable & Fruit Improvement Center, Texas factors affecting popping. Seed of a photoperiod insensitive, temperate A&M System Uvalde TX; [email protected] adapted nuña bean breeding line, PB24, was produced at the Arlington Agriculture Research Station, Arlington, WI, and evaluated in a hot John Jifon air popper. The experimental design was a factorial with three levels Texas A&M University, Texas Agricultural Experiment Station Weslaco of popping time (60, 90, and 120 seconds), five levels of chamber TX; [email protected] temperature (101, 146, 208, 244, and 268 °C), and eight levels of Kil Sun Yoo seed moisture 2.5%, 3.2%, 5.2%, 6.6%, 8.3%, 12.0%, 15.3%, and 20%. Larger mean squares were observed for main effects and first Texas A&M University-VFIC College Station TX; [email protected] order interactions associated with seed moisture content and chamber Several important virus resistance genes have been documented from temperature compared to popping time. A combination of seed mois- Capsicum chinense germplasm, including pvr1 and Tsw. However, ture below 5%, popping chamber temperatures above 240 °C, and there are only a few reports of genes or resistance traits related to

HORTSCIENCE, VOL. 43(4), JULY 2008 1151 other pathogens or arthropods in this species. The pepper improvement Specified Source(s) of Funding: Department, College, State and/or project at Texas AgriLife Research center at Weslaco has investigated HATCH resistance to aphids, leafminers, mites, powdery mildew, bacterial leaf spot, and CMV in diverse germplasm accessions of C. chinense for the last 8 years. In addition, we have examined heat tolerance, plant 9:45–10:00 am habit, concentrated fruit set, and capsaicin levels and the importance of heterosis to these traits. Resistance to powdery mildew (Leveillula Development of Broccoli Adapted to taurica), has been verified in multiple C. chinense lines by both natural Summer Conditions in the field infection and controlled inoculation in a greenhouse. Resistance Southeastern United States in PI 315017 has been backcrossed into multiple C. annuum lines to Mark W. Farnham* develop resistant jalape os and other commercial types. Inheritance in USDA-ARS-U.S. Vegetable Laboratory, Charleston SC; mfarnham@saa. two different families appears to involve two recessive genes based ars.usda.gov on Chi-Square analyses. Resistance to aphids and leafminers has been observed in replicated field plots, based on natural infestation in PI Thomas Bjorkman 260491, PI 543184, and Guadeloupe Red C. chinense accessions. Cornell Univ., Geneva NY; [email protected] Resistance to cotton aphids was confirmed in PI 543184 by controlled inoculations in cages, with jalapeno as the susceptible check. This For over ten years, the USDA-ARS broccoli breeding and genetics may contribute to CMV resistance observed in three consecutive field project at the U.S. Vegetable Laboratory (USVL) in Charleston, South trials at Uvalde, where more than 90% of C. annuum entries showed Carolina has conducted a breeding program in which broccoli has been severe symptoms, but several C. chinense, including PI 543184 and its selected for adaptation to summer environments. The program was initiated in the early 1990s using a few commercial hybrids available progeny evinced resistance to the virus. Several new experimental F1 hybrid Habanero-type peppers have been developed, and exceptional at the time that showed some potential for head production under heterosis for yield, earliness, and fruit quality have been documented. summer conditions and other noncommercial broccolis obtained from Several of these demonstrated resistance to both PepMoV and TSWV, other sources. The program uses a conventional pedigree breeding ap- under controlled inoculations, and additional field resistance to CMV, proach in which different inbreds are crossed to one another to form bacterial leaf spot and powdery mildew has been observed. hybrids that are subsequently selfed to create segregating populations. Through several rounds of selection and recombination, lines increas- Specified Source(s) of Funding: Department, College, State and/or ingly adapted to hot and humid summer conditions at Charleston HATCH Federal competitive Private (Association, Foundation, In- have been identified. These USVL summer broccoli lines appear dustry) Federal Program Name, Award Number: Designing Foods for to be different than any broccoli lines designated as “heat tolerant” Health USDA CSREES 2004-34402-14768, 2006-34402-17121 developed by western U.S. breeding programs. Western broccoli is generally selected under hot day/cool night conditions, while USVL lines have been selected under hot day/hot night conditions. Field 9:30–9:45 am studies conducted at different locations and times of the year indicate that USVL lines adapted to southeastern summer conditions perform Modelling the Effects of Drought Stress on Leaf very similar regardless of the temperature conditions they are grown Development in a Brassica oleracea in. On the contrary, western broccoli lines perform well under optimal DH-Population using n-phase Linear Functions temperature conditions (e.g., in the autumn), but do not head at all or Ralf Uptmoor only produce very poor quality heads in summer. These observations Leibniz Universität Hannover, Institute of Biological Production Systems lead to a hypothesis that the USVL broccoli is different than western Hannover, Germany; [email protected] “heat tolerant” broccoli. The USVL broccoli might be more accurately designated “heat resistant “ or “heat insensitive .” Mildred Osei-Kwarteng Leibniz Universität Hannover, Institute of Biological Production Systems, Hannover, Germany; [email protected] Oral Session 37: Human Issues/Education and Outreach Hartmut Stützel* Leibniz Universität Hannover, 30419 Hannover, Germany; stuetzel@gem. Thursday, 24 July 10:00–11:15 am Salon 8 uni-hannover.de Moderator: Tina Waliczek, [email protected] Quantitative traits are too complex to be described by single values, since phenotypes change with time and environmental conditions. 10:00–10:15 am Variation within populations can be described by genotype specific parameterization of response curves on time and influential envi- Gardening as a Physical Activity for Health ronmental factors like soil water status. We used a two-phase linear in Older Adults function to describe pre-flowering leaf area development in a Brassica Sin-Ae Park* oleracea DH-population. In order to illustrate the effects of drought on Kansas State University, Manhattan KS; [email protected], leaf growth, the function was combined with a plateau function that estimates the soil water status at which stress effects begin to reduce Candice Shoemaker leaf expansion, a genotype specific slope of the response to soil water Kansas State University, Manhattan KS; [email protected] status, and the soil water status at which leaf expansion becomes zero. Mark Haub A total number of 14 QTLs was detected on five model parameters. Nine of these QTLs co-localized to QTLs detected on data of static Kansas State Univeristy, Manhattan KS; [email protected] leaf area measurements and osmotic adjustment. The entire model At least 30 minutes of moderate intensity physical activity (PA) on was able to discriminate between genotypes during later growth most days of the week is recommended to maintain or improve health. stages under well watered and drought stress conditions. However, the In our previous research, gardening was determined to offer moderate predictability was largely reduced when drought stress became more intensity PA, thus may offer the health benefits associated with PA. severe at the final measurement dates. Independent evaluation trials This study was conducted to compare the physical and psychological showed that the accuracy of the model was on the same level or even health conditions and leisure-time activities, particularly PAs of older increased when genotype specific input parameters were replaced by gardeners and non gardeners. Fifty-three elderly (age ranged 58-86 allele specific QTL effects.

1152 HORTSCIENCE, VOL. 43(4), JULY 2008 years) were randomly recruited from the community of Manhattan, Contemporary children’s gardening began in 1993 when the Ameri- KS. Based on results of the Community Healthy Activities Model can Horticultural society held its first symposium entitled “Children, Program for Seniors (CHamPS) questionnaire, subjects were classi- Plants, and Gardens: Educational Opportunities.” The focus of the fied as Active-Gardeners (n=11, subjects met the PA recommendation symposium was to demonstrate ways in which children’s gardens through gardening), Gardeners (n=14, subjects did not meet the PA could support educational curricula. Much research has been conducted recommendation through gardening but did garden for 120-150 minutes on the skills children need to have the social competence to achieve per week at both low and moderate intensity), and Non-Gardeners (n their goals successfully and appropriately. These skills include: life, = 28). Overall physical and mental health conditions were determined interpersonal, anger control, and stress management skills. Each of with the Short Form 36 Health Survey (SF-36), hand function ability these skills can be learned or practiced in the garden. There is limited was determined by hydraulic hand dynamometer and pinch gauge, and research to show the connection between life skills and gardening bone mineral density (BMD) was determined by dual-energy X-ray for children. This purpose of this study was to assess the effects absorptiometry. Active-Gardeners were significantly different than that gardening/plant activities have on children’s life skills and the Gardeners and Non-Gardeners in physical health, hand strength, and effectiveness of the Junior Master Gardener curriculum, Literature pinch force (P d 0.05). There were no differences in mental health in the Garden, in increasing those skills. This study focused on five between the three groups, but all groups had scores higher than the life skills: teamwork, self-understanding, leadership, decision mak- norm for elderly over 55 years old. There was no difference in BMD ing skills, and communication skills. Approximately 130 third-grade between the groups, but all participants had higher scores than the students from a Lee County, AL, school were equally divided into standard BMD value of their age. The only significant difference control and experimental groups and each student was given the Youth of caloric expenditure in leisure-time PAs between the groups was Life Skills Inventory as a pre-and post-test. The experimental group gardening(P < 0.001). These results begin to provide direct evidence participated in eight gardening/plant activities after the pre-test while that gardening, as a leisure-time PA, can help older adults meet the PA the control group did not complete the activities. The activities from recommendation and experience the health benefits associated with a the Literature in the Garden curriculum are based on six children’s physically active lifestyle. literature books that are all related to gardening or nature. The results of the study may validate that Literature in the Garden supports life Specified Source(s) of Funding: Department, College, State and/or skills as well as teaches children about plants and nature. Also, as more HATCH Grant from Center on Aging at Kansas State University data is gathered, the amount of information about children’s gardening as its related to life skills will increase, hopefully establishing a theoretical precedent. 10:15–10:30 am Specified Source(s) of Funding: Department, College, State and/or Horticultural Responsibility Improves Seniors’ Sense of HATCH Well-being Angela O’Callaghan* University of Nevada, Reno, Las Vegas; [email protected] 10:45–11:00 am Claudia Collins The Influence of Gardening on Eating Habits and Universtiy of Nevada, Reno, Las Vegas; [email protected] Nutrition Knowledge In order to determine whether the health and well-being of elderly Tina Waliczek* residents of an assisted living facility would improve with horticultural Texas State University, San Marcos TX; [email protected] responsibility, 18 persons were enrolled in a 4-week indoor gardening Jayne Zajicek program. The assisted living housing development was the first specifi- Texas A&M University, College Station TX; [email protected] cally geared for low-income seniors. Self-selected participants were tested and interviewed at the beginning of the program concerning their R. Daniel Lineberger satisfaction with their living situations and their belief in their control Texas A&M University, College Station TX; [email protected]

over their lives, in addition to their gardening experiences (pre-test). ORALS–THURSDAY This program included transplanting houseplants, starting plants from The purpose of this study was to investigate the effect of gardening on seed, and maintaining them in small apartments. Participants selected eating habits and nutrition knowledge. A nutritional survey was posted the plants for which they would be responsible. The questions about for four months on one of the largest online resources for Texas Master their control over their lives were repeated at the end of the study (post- Gardeners within the Aggie Horticulture network, the Texas Master test). At that time, all plants had survived, and wellness indicators of Gardener Web page. During that time, 402 responses were gathered. all participants improved statistically. The participants who remained Additionally, identical “paper/pencil” format surveys were distributed at the facility were interviewed again four months after the conclusion to garden, church, social, and community groups with approximately of the study (post post-test). While there was some decrease in well- 400 responses received. In each group of participants, respondents ness parameters, an overall increase in wellness indicators persisted differentiated themselves as gardeners or non-gardeners by respond- relative to the initial values. ing positively or negatively to the survey question, “Do you garden?” Survey questions included those that asked the frequency at which Specified Source(s) of Funding: Department, College, State and/or respondents consumed certain foods including fruits and vegetables, as HATCH well as sweets and salty snacks. Other questions asked respondents to choose from two responses the food that was the most healthful option in terms of fat, fiber, and salt content. Results for the study compared 10:30–10:45 am gardeners’ and non-gardeners’ responses to survey questions on their frequency of eating certain kinds of foods, as well as on the questions The Effects of Literature in the Garden on Children’s relating to knowledge of nutrition. In addition to the evaluation of Life Skills habits and knowledge of nutrition of gardeners and non-gardeners, Ann Fleener* demographic comparisons were made amongst gardeners. Auburn University, Auburn AL; [email protected] Specified Source(s) of Funding: Department, College, State and/or Carolyn W. Robinson* HATCH Federal Program Name, Award Number: U.S. Department Auburn University, Auburn AL; [email protected] of Agriculture - Agricultural Research Station

HORTSCIENCE, VOL. 43(4), JULY 2008 1153 11:00–11:15 am Two Buddleia cultivars, B. davidii ‘Potters Purple’ and Buddleia Development of Healthy Snack Alternatives ‘Lochinch’, were transformed using Agrobacterium tumefaciens strain EHA105 harboring binary vector pBI121 carrying the neomycin phos- Using Local Produce photransferase gene (nptII) and -glucuronidase (GUS) gene (uidA). Sheeka Afaisen* Plants were recovered from the Agrobacterium-infected leaf tissues College of Natural and Applied Sciences, University of Guam, Mangilao, via organogenesis on woody plant medium (Wpm) supplemented Guam (USA); [email protected] with 5 M 6-benzyladenine (BA) plus 5 M indole-3-butyric acid (IBA) for ‘Potters Purple’ or 20 M BA plus 4 M IBA for ‘Lochinch’ and Joanne Schlub 250 mg·L-1 cefotaxime plus 500 mg·L-1 carbenicillin plus 40 mg·L-1 College of Natural and Applied Sciences, University of Guam Mangilao, kanamycin (CCK40). Factors including co-cultivation time (3, 6, and Guam (USA); [email protected] 9 days) and tissue wounding affecting the transformation frequency Kristen Cruz were investigated. After 9 days co-cultivation with the Agrobacterium, College of Natural and Applied Sciences, University of Guam Mangilao, an average of 32% of leaf explants produced shoots from CCK40 Guam (USA) [email protected] medium. Wounding leaf tissues with a blunt-teeth scissors enhanced plant recovery from Agrobacterium-infected tissues. Transformation Jian Yang was verified with polymerase chain reaction (PCR) and southern blot College of Natural and Applied Sciences, University of Guam Mangilao, analysis. Southern blot analysis confirmed that one to three copies of Guam (USA); [email protected] the transgenes were integrated into the plant genome. Transgenic in Mari Marutani vitro shoots were rooted in half-strength MS medium containing 0.5 College of Natural and Applied Sciences, University of Guam Mangilao, M naphthalene acetic acid (NAA). Rooted plants were transferred Guam (USA); [email protected] to potting mix and grown in the greenhouse. This research shows a potential for future improvement of Buddleia species. Healthy snack alternatives using local produce were developed. In the initial phase, three crops, breadfruit (Artocarpus altilis), bananas (Musa Specified Source(s) of Funding: Department, College, State and/or spp.), and purple sweet potatoes (Ipomoea batatas) were dehydrated to HATCH Private (Association, Foundation, Industry) Landscape Plant make chips without using oils. Purple sweet potato (PSP) chips were Development Center selected for further development based on consistency of texture, color, and flavor, as well as the availability of the crop and ease of preparation. The objective of this study is to evaluate the sensory quality of 10:15–10:30 am dehydrated and microwave PSP chips. Three methods of making PSP Big Vein-resistant Lettuce Carrying chips were studied: baking, dehydrating, and using a microwave. Since Inverted Repeats of the Coat Protein Gene baked chips did not have a favorable color and taste, the microwave and dehydrated chips were selected for further evaluation by way of of Mirafiori Lettuce Virus a preference test and a consumer acceptance test. In the preference Yoichi Kawazu* test, the dehydrated PSP chips were shown to be equally preferred as National Institute of Vegetable and Tea Science Mie, Japan; the commercial chips, while the microwave PSP chips were shown [email protected] to be significantly less preferred than the dehydrated and commercial Yuji Noguchi chips. The dehydrated PSP chips were shown to be comparable to the commercial chips and more accepted than the microwave chips. The National Institute of Vegetable and Tea Science Mie, Japan; ynogu@affrc. overall acceptance of the dehydrated PSP chip can be attributed to its go.jp desirable color, flavor, texture, crispiness, and sweetness. The PSP Lettuce big-vein disease is a soil-borne viral disease found in major chips prepared through dehydration exhibited good sensory quality lettuce production areas worldwide. The most desirable method to and consumer acceptance, indicating a potential market on Guam. control big-vein disease is the use of resistant cultivars. However, Specified Source(s) of Funding: Federal competitive USDA-CREES- cultivars released to date do not exhibit a high level of resistance Multicultural Higher Education because breeding sources with high resistance to the disease have not been found in lettuce (Lactuca sativa L.). Transgenic strategies are attractive alternative methods for developing lettuce that is more resistant to the disease. Two viruses, lettuce big-vein associated virus (LBVaV) and mirafiori lettuce virus (MiLV), are associated with the disease, and MiLV is regarded as the causal agent of lettuce big-vein Oral Session 38: Biotechnology 3 disease. In this study, we introduced the inverted repeats of the MiLV coat protein (CP) gene into lettuce to produce MiLV-resistant lettuce. Thursday, 24 July 10:00 am–12:00 pm Salon 7 Forty T1 lines were analyzed for resistance to MiLV, and two lines Moderator: Dennis J. Gray, djg@ufl.edu (lines 408 and 495) were selected as resistant to MiLV. Both lines were susceptible to LBVaV, and line 495 showed higher resistance to MiLV than line 408. Further analysis indicated that line 495 showed 10:00–10:15 am resistance to MiLV and big-vein expression in a growth chamber and Agrobacterium-Mediated Transformation of Buddleia a greenhouse. Small interfering RNA (siRNA) molecules derived from Species the transgene were detected in plants of line 495. Detection of siRNAs suggests that RNA silencing is active against MiLV CP gene-derived Wenhao Dai* RNA in plants of line 495 and that the siRNAs contribute to MiLV North Dakota State University Fargo ND; [email protected] resistance. The MiLV-resistant lettuce produced in this study can be Yuanjie Su used as a resistant cultivar or as a breeding source. North Dakota State University Fargo ND; [email protected] Specified Source(s) of Funding: Federal competitive The Scientific Hongxia Wang and Technological Research Council of Turkey (TUBITAK), Project North Dakota State University Fargo ND; [email protected] No:105 O 056 Cielo Castillo North Dakota State University Fargo ND; [email protected]

1154 HORTSCIENCE, VOL. 43(4), JULY 2008 10:30–10:45 am that threatens many production areas. Damage caused by sting nema- Transformation and Regeneration of Transgenic tode Belonolaimus longicaudatus may lead to almost 100% of yield loss in localized areas of infested fields. The most efficient way to ‘W. Murcott’ (Nadorcott) Mandarin Using a control sting nematode population is the usage of methyl bromide, Protoplast-GFP Transformation System a fumigant that effectively reduces the nematode population. The Ahmad Omar* use of this fumigant has been restricted to critical use exemptions. University of Florida, Lake Alfred FL; omar71@ufl.edu The goal of this work is to test if bioengineering of strawberry plants can confer resistance to this destructive pest. Cystatin, a cysteine Milica Calovic protease inhibitor, is a good candidate since cysteine protease has University of Florida, Lake Alfred FL; milica@ufl.edu been shown a major digestive enzyme in nematode intestine. Cyf1 Hesham El-Shamy (FaCPI-1) is a strawberry cystatin reported to be resistant to two Zagazig University, Egypt Zagazig, Egypt [email protected] major fungal diseases Botrytis cinerea and Fusarium oxysporum in strawberry (Martinez et al., 2005). However, the Cyf1 inhibitory Hyun Joo An activity against nematode cysteine protease has not been tested. In NISA, RDA Jeju, Seogwipo, South Korea joo@ufl.edu this study, we have identified several strawberry cystatins (FaCys) that comprise a small multigene family. Variant-specific expression Jude Grosser patterns have been examined. The inhibitory activity of strawberry University of Florida, Lake Alfred FL; jgrosser@ufl.edu cystatin family members has been tested in vitro by expressing the The approach of using genetic transformation offers an attractive FaCys recombinant proteins in Escherichia coli. Inhibitory activity alternative to the conventional genetic improvement of Citrus sp. against papain and human legumain, as well as the proteases from Genetic transformation of several Citrus genotypes has been achieved nematode extract was ascertained. Transgenic strawberry plants were by co-cultivating different explants (mainly juvenile) with Agrobac- generated to test the effect of FaCys on sting nematodes in soil. The terium tumefaciens. However, mandarin is considered to be the most successful identification and deployment of plant cystatins may be difficult Citrus sp. for transformation using the Agarobacterium- a useful tool in engineering nematode resistant plants, and also may mediated system. ‘W. Murcott’ mandarin (a hybrid of ‘Murcott’ and substantially curb use of volatile fumigants, decreasing environmental an unknown pollen-parent) is a commercially important cultivar impacts of strawberry farming in Florida. grown in many regions around the world. Few reports describe the Specified Source(s) of Funding: Federal competitive Federal Program transformation and regeneration of transgenic lines of mandarin cul- Name, Award Number:; Department of Agriculture T-STAR tivars. Strong influence of the genotype in citrus organogenesis and genetic transformation suggested the need for specific studies on in vitro protocols for efficient plant transformation and regeneration. We undertook the study to develop efficient direct DNA uptake using 11:00–11:15 am PEG-mediated transformation of mandarin protoplasts and regenera- Transgenic Grapevine Rootstocks for tion of transgenic plants, using our protoplast-GFP transformation Pierce’s Disease Resistance system. Plasmid DNA (pAO3), encoding the non-destructive select- Sadanand Dhekney* able marker GFP (Green Fluorescent Protein) gene and the cDNA of the Xa21 Xanthomonas resistance gene from rice, was transformed University of Florida/IFAS Apopka FL; sadanand@ufl.edu into ‘W. Murcott’ embryogenic protoplasts. Following protoplast Zhijian Li culture in liquid medium and transfer to solid medium, transformed Univeristy of Florida/IFAS Apopka FL; zjli@ufl.edu colonies were microscopically selected via expression of GFP, physically separated from non-transformed tissue, and cultured on somatic Donald Hopkins embryogenesis induction medium. More than 50 transgenic embryoids University of Florida/IFAS Apopka FL; dhop@ufl.edu were recovered. So far, eight transgenic plantlets were regenerated and Thomas Zimmerman cultured on rooting medium. PCR analysis revealed the presence of University of the Virgin Islands Kingshill, St. Croix VI; [email protected] the Xa21 and the GFP genes in the transgenic plantlets. The recovery ORALS–THURSDAY of multiple transgenic plants will be expedited by in vitro grafting. Dennis Gray* The transgenic plants have shown stable GFP expression. Following University of Florida/IFAS Apopka FL; djg@ufl.edu successful acclimation in the greenhouse, molecular characterization including Southern blot analysis and Western blot analysis will be Use of transgenic rootstocks to impart Pierce’s disease (PD) resistance performed to study transgene integration and expression in these to non-transgenic scions of grapevine varieties would eliminate con- transgenic plants. cerns of transgene flow by pollen and/or seed dispersal. Embryogenic cultures were initiated from rootstocks Vitis champinii ‘Ramsey’, Specified Source(s) of Funding: Department, College, State and/or Vitis riparia ‘Gloire’, and Vitis hybrids ‘Freedom’, ‘Harmony’and HATCH ‘Richter 110’. Two genes encoding anti-microbial peptides LIMA-A and LIMA-B, plus an egfp/nptII fusion gene were placed under the control of a CaMV 35S derived bidirectional promoter complex and 10:45–11:00 am introduced into Agrobacterium ‘EHA 105’. Somatic embryos (SE) at the mid-cotyledonary stage were co-cultivated with Agrobacterium Evaluation of Strawberry Cystatin Gene Family and transgenic SE were recovered via secondary embryogenesis. Members as Sting Nematode Antifeedants ELISA was used to detect the presence of transpeptides in regenerated Kevin Folta* transgenic rootstocks. Non-transgenic scions of commercial grapevine University of Florida, Gainesville; [email protected]fl.edu varieties are currently being grafted on transgenic rootstocks to detect the presence and movement of transpeptides in the scions and for field Hui Yi Wang* evaluation of PD resistance. Univeristy of Florida ,Gainesville; heidiwang@ufl.edu Specified Source(s) of Funding: Federal competitive -Department, Sasha Ricaurte College, State and/or HATCH FDACS Viticulture Trust Fund Fed- Univeristy of Florida, Gainesville; sar821@ufl.edu eral Program Name, Award Number: USDA Tropical, Sub-Tropical Strawberry cultivation in Florida faces a serious nematode problem Agricultural Research Grant

HORTSCIENCE, VOL. 43(4), JULY 2008 1155 11:15–11:30 am pollen shed from transgenic vines to receptive flowers over varying Transgenic Apple Lines Carrying Vfa Genes in Tandem distances allows confident determination of pollen-mediated gene flow. Thus, the GFP marker system provides a convenient method for Resistance to Apple Scab to address risk assessment and to answer outstanding questions of Ruth Soria-Guerra grapevine reproductive biology in general. University of Illinois at Urbana-Champaign Urbana IL; [email protected] Specified Source(s) of Funding: Department, College, State and/or Mingliang Xu HATCH Federal competitive FDACS Viticulture Trust Fund Federal China Agricultural University Beijing, China; [email protected] Program Name, Award Number: USDA Tropical, Sub-Tropical Ag- ricultural Research Grant Schuyler Korban* University of Illinois at Urbana-Champaign Urbana IL; [email protected] Apple scab, incited by the fungal organism Venturia inaequalis, is 11:45 am–12:00 pm one of the most serious diseases of apple. Most major apple cultivars In silico Estimations of Height and Diameters of Daylily are susceptible to this disease. Although several sources of genetic resistance to apple scab are known, resistance encoded by the Vf Hybrids using Artificial Neural Networks and Multiple locus derived from Malus floribunda 821, has been the most widely Linear Regression Models used source. A total of four Vf paralogs have been identified in the Vf Ramana Gosukonda* locus (Vfa1, Vfa2, Vfa3, and Vfa4). Previously, we have determined Fort Valley State University Fort Valley GA; [email protected] that Vfa1 and Vfa2 are functional, while Vfa3 and Vfa4 are not. A high homology in the C-terminal region of Vfa1 and Vfa2 suggests Masoud Naghedolfeizi that these two Vf paralogs activate the same defense system in apple. Fort Valley State University Fort Valley GA; [email protected] Here, we report on the development of transgenic lines carrying the Daylilies (Hemerocalli spp.) are important in international trade and two Vfa genes in tandem. cDNA clones of Vfa1 and Vfa2 genes, includ- domestic economy with revenues over millions of dollars per year. ing native promoter and 3’-UTR region were cloned into the binary Daylily growers are often interested in knowing what pod and pol- vector pCamBIA2301 to obtain pCAUVfa1&2. This construct was len parents would result in a desired hybrid, as the seeds bear by the transferred to Agrobacterium tumefaciens strain GV3101. Leaf tissues pod parent frequently results in hybrids with different patterns. from in vitro-grown proliferating shoots of the scab-susceptible apple Further, the growers have to wait at least a year before these hy- cv. ‘Honeycrisp’ were transformed with the construct pCAUVfa1&2 brids can grow and exhibit patterns. Use of artificial neural network via Agrobacterium-mediated transformation. Putative transformed (ANN) models could provide this information in advance to growers shoots were observed after 8-10 weeks, and these were then transferred for efficient breeding. The objective is to make a better use of available to rooting medium, and acclimatized. Transgenic apple lines were data for estimating daylily hybrid in silico using ANN and/or regres- confirmed for presence of the transgene using PCR and GUS assays. sion models. In the initial training and testing, ANN and regression Levels of the Vfa transgene expression will be determined using models were employed to predict height and diameter of hybrids from Northern and Western blot analyses. Characterization of these plants known characteristics of parents used in hybridization. About 800 pat- will have implications for the development of new apple varieties terns were used in training and 400 were used in testing. Each pattern with resistance to apple scab. contains five fields of input data and two fields of outputs. The input Specified Source(s) of Funding: Department, College, State and/or data includes ploidy and the heights and diameters of both parents HATCH Illinois Council for Food and Agricultural Research (C-FAR) and the outputs consist of height and diameter of the hybrid (child). project no. IDA CF 06FS-0303. Data pre-processing was performed to meet the format requirements of ANN and regression models. Backckpropagation and Kalman filter learning algorithms were used to develop nonparametric models be- 11:30–11:45 am tween the input and output data sets. Prediction plots for both height Tracking Pollen-mediated Gene Flow in Transgenic and diameter indicated that the regression model had a better accuracy in predicting unseen patterns. However, ANN models were able to Grapevine more robustly generalize and interpolate unseen patterns within the Dennis Gray* domain of training. Our analysis reveals that neural networks have University of Florida/IFAS, Apopka FL; djg@ufl.edu great potential for improving model predictions in nonlinear decision contexts without sacrificing performance in linear decision contexts. Zhijian Li The conclusion is based on small sample of data and more research Univeristy of Florida/IFAS, Apopka FL; zjli@ufl.edu is needed to verify the applicability of these models to a much larger Sadanand Dhekney sample size. University of Florida/IFAS, Apopka FL; sadanand@ufl.edu Specified Source(s) of Funding: Federal competitive Thomas Zimmerman University of the Virgin Islands, Kingshill, St. Croix VI; [email protected] Quantitative information has been lacking concerning distances that Oral Session 39: grapevine pollen can move to successfully fertilize outlying vines. However, such information has become important with the establish- Culture & Management: Vegetable Crops 3 ment of transgenic grapevine field tests and the need to assess the risks Thursday, 24 July 10:00–11:15 am Salon 6 associated with gene flow in the environment. Stable insertion of the egfp gene, which codes for green fluorescent protein (GFP), into grapevine Moderator: William Neily, [email protected] has become routine. Expression of GFP serves as a convenient marker to detect transgene presence because it can be readily visualized. The 10:00–10:15 am GFP gene segregates as a dominant in transgenic grapevines. With grapevines that contain a single copy of egfp, the segregation ratio, Stimplex from Ascophyllum nodosum Improves Salinity as judged by GFP expression in endosperm and zygotic embryos, is Tolerance in Tomato 75% GFP positive/25% GFP negative in selfed transgenic plants and 50% GFP positive/50% GFP negative in non-transgenic vines fertilized Will Neily* with transgenic pollen. Correlation of wind direction and speed with Acadian Seaplants Ltd., Cornwallis NS Canada [email protected]

1156 HORTSCIENCE, VOL. 43(4), JULY 2008 Laurel Shishkov concentration in non-treated control plots. There were no significant Acadian Seaplants Ltd., Cornwallis NS Canada [email protected] marketable yield differences in plots treated with either AN + PS or ASN. Average marketable yield ranged between 61.6 and 63.2 t/ha in Dayna Titus the S-treated plots. In contrast, average yield in the AN-treated plots Acadian Seaplants Ltd., Cornwallis NS Canada [email protected] was 41.9 t/ha, which was 44 and 42% less than the yields in the AN Soil salinity is an increasingly important abiotic stress limiting crop + PS and ASN-treated plots. These results suggest that soil analysis productivity worldwide. Seaweed extracts are known to improve root should be performed in tomato fields before planting to determine and shoot development of agricultural plants as well as to alleviate appropriate S application rates. Based on these results, it seems that S some symptoms typically associated with salinity and drought stress. A fertilization should be considered for tomato production and it should greenhouse experiment was designed to test the effects of a commercial be evaluated in other vegetable fertilizer programs. seaweed extract (Stimplex , a derivative from Ascophyllum nodosum) Specified Source(s) of Funding: Private (Association, Foundation, on salinity-stressed tomatoes, Lycopersicon esculentum ‘Florida 91’. Industry) Industry/Association Program Name, Award Number: A 200 mM NaCl drench was applied to newly transplanted 20 day Honeywell, Inc. old seedlings along with either a commercial fertilizer (10-52-10) or fertilizer plus Stimplex applied at rates of 5 and 10 mL/L. The seedlings were grown in 8-0-6 cell packs at 23:20 °C L:D under natural light 10:30–10:45 am supplemented with HID lighting for 16 hours daily. After fourteen days, the roots and leaves of plants selected randomly from each treatment Effect of Nitrogen Rates on Yield and Quality of Tomato were examined with both WinRhizo root and WinFolia leaf image Grown in the Spring with Sub-surface (Seepage) analysis systems. Significant increases in root length (122%), surface Irrigation area (68%), and tip number (78%) were observed in salt-stressed seedlings where Stimplex was applied compared to the fertilizer controls. Monica Ozores-Hampton* An increase in leaf surface area and a reduction in plant mortality University of Florida/IFAS/SWFREC, Immokalee; [email protected] were also observed in Stimplex -treated plants. The results show that Eric Simonne Stimplex applied as a root drench provides some degree of protection University of Florida, Gainesville; [email protected]fl.edu against salinity stress in young tomato seedlings. Phyllis Gilreath Specified Source(s) of Funding: Private (Association, Foundation, University of Florida, Palmetto; phyllisg@ufl.edu Industry) Eugene McAvoy University of Florida Labelle; [email protected]fl.edu 10:15–10:30 am Steven Sargent Influence of Sulfur Fertilization on Tomato Growth and University of Florida, Gainesville; sasa@ufl.edu Development Daniel McClure Camille Esmel* West Coast Tomato, Inc., Palmetto; [email protected] University of Florida, Wimauma; [email protected] Thomas Wilkes Bielinski Santos* West Coast Tomato, Inc., Palmetto; [email protected] University of Florida, Wimauma; bmsantos@ufl.edu Kelly Morgan Eric Simonne University of Florida, Immokalee; conserv@ufl.edu University of Florida, Gainesville; esimonne@ufl.edu The optimum fertilization management and application section of Jack Rechcigl the Water Quality/Quantity Best Management Practices (BMP) for

University of Florida, Wimauma; rechcigl@ufl.edu Florida Vegetables and Agronomic Crops manual are based on the ORALS–THURSDAY recommendations of University of Florida (UF-IFAS) (224 kg/ha of Joseph Noling N for tomato grown in any seasons, soil types or irrigation methods). University of Florida, Wimauma; jnoling@ufl.edu With subsurface irrigation, fertilizer is applied broadcast in the bed Sulfur (S) is an important component in plant physiology, because of as a cold mix (7% of N and K and 100% of P and micronutrients) and it is required for the synthesis of the amino acids cysteine and me- in two bands (with the remaining N and K or hot mix ) placed on the thionine. Sulfur deficiencies are often confused with other deficient bed shoulders. The objective of this study was to evaluate the effect elements such as nitrogen (N). This could be due to the synergistic of N rates (0 to 448 kg/ha) in the hot mix on crop nutritional status, effect between N and S as they are both important to photosynthesis. yield and fruit quality of ‘Florida 47’ tomato grown in the spring with Tomato production in Florida is typically on deep Spodosols (fine subsurface irrigation (perched water table). Spring conditions in central sand) with low organic matter (>2%) and therefore inherently low in Florida are dry, with a low chance of frost. In 2007, a dry year (254 organic and inorganic S. Two field studies were conducted to determine mm of rain at the end of the season), weekly sap testing indicated that the effect to determine the effect of S fertilization on tomato yield and N rates lower than 112 kg/ha resulted in insufficient NO3-N petiole foliar S concentration. The soil had very low S content (<30 ppm) and concentrations (600 mg/L) 60 days after transplanting. The N rates 1.5% organic matter. Fertilizer source treatments were a) ammonium that resulted in sufficient petiole NO3-N until second and third harvest nitrate (AN; 34% N) at a rate of 342 kg/ha of N; b) AN + potassium were 315 and 448 kg/ha. Yield components responses to N rates were sulfate (PS; 23% S and 55% K) at rates of 342 + 391 kg/ha of N and quadratic. Extra-large yield at first (XL-YL1), second (XL-YL2), third S; c) ammonium sulfate nitrate (ASN; 26% N and 14% S) at a rate of (XL-YL3), all-harvests cumulated (XL-YT), and total marketable yield 342 + 391 kg/ha of N and S; and d) a non-treated control. Muriate of (TMKT; all in 25-lb boxes/ha) represented 65%, 15%, 1%, 81%, and potash (60% K) was used to balance total K amounts in each treatment 100% of total marketable yield, respectively. The regression equations to ensure that this nutrient was under non-limiting conditions. Plots XL-YL1=-0.0119x2 + 5.91x + 1,599, XL-YL2 = -0.0059x2 + 4.17x - treated with either rate of AN or non-treated had the lowest foliar S 11.6, XL-YL3 = -0.0009x2 + 0.49 11.26, XL-YT = -0.0187x2 + 10.57x concentration, ranging between 0.55 and 0.53%. However, plots treated + 1,576 and TMKT= -0.0222x2 + 13.03x + 1,883 (R2 = 0.19, 0.83, with S-containing fertilizers increased foliar S concentration when 0.25, 0.46, and 0.63, respectively) had maximum yields corresponding compared with the non-treated control and AN-treated plots. Average to 278, 397, 307, 314 and 328 kg/ha of N. Fruit soluble solids concen- S concentration was about 0.74%, which was 40% higher than the tration, total titratable acidity and pH at harvest did not respond to N rates. The results of this one-year study under dry conditions suggested

HORTSCIENCE, VOL. 43(4), JULY 2008 1157 that N rates ranging between 278 and 328 kg/ha resulted in highest (phytophthora-tolerant) and Camelot (phytophthora-susceptible), yields of marketable-quality tomato, which are slightly greater than were arranged in a split-block design with cultivar as the main block current recommendations with three harvests. factor and fertility treatments as the split-block factor. Season long fertility treatments were 1) 201.8 kg/ha Nitrogen (20-20-20); 2) 336 Specified Source(s) of Funding: Department, College, State and/or kg/ha Nitrogen (4-0-8); 3) 201.8 kg/ha Nitrogen (liquid Nitamin ); HATCH 4) 151 kg/ha Nitrogen (liquid Nitamin ); 5) 201.8 kg/ha Nitrogen pre-plant (Granular Nitamin ); and 6) 151 kg/ha Nitrogen pre-plant (granular Nitamin ). Treatments 1-4 were applied through the drip 10:45–11:00 am weekly. Treatments 5 and 6 were granular materials applied after Developing an Integrated Crop Management System bed making, but prior to laying plastic in two bands per bed 2 inches for Managing Soil-borne Diseases in Sweet Pepper (5 cm) from the drip tape. Additionally, phosphorus, potassium, and boron were applied at the same rates for all plots season long. Each Production plot was harvested six (2006) or seven (2007) times and fruit graded Deng-Lin Wu and weighed according to marketable, marketable with silvering and AVRDC–The World Vegetable Center Shanhua, Tainan, Taiwan culls. Both years, harvest date × variety interactions was significant [email protected] with ‘Aristotle’ producing more fruit with silvering at all harvest dates except one. ‘Aristotle’ produced significantly more marketable fruit Manuel Palada* than ‘Camelot’ at all harvest dates. Nitrogen fertility was not a factor AVRDC–The World Vegetable Center Shanhua, Tainan, Taiwan in development of silvering in 2006. In 2007, there were no significant [email protected] interactions with fertility, but the cultivar main effect was significant Tien-Chen Wang (P = 0.0092). Treatment 1 - 201.8 kg/ha Nitrogen (20-20-20) and AVRDC—The World Vegetable Center Shanhua, Tainan, Taiwan 2 - 336 kg/ha Nitrogen (4-0-8) had more silvered fruit than treatment [email protected] 5 - 201.8 kg/ha Nitrogen pre-plant (Granular Nitamin ). All other treatments were not significantly different from either 1, 2, or 5. Sweet pepper production during the hot wet season in lowland humid tropics is constrained by high temperatures, flooding and a high Specified Source(s) of Funding: Private (Association, Foundation, incidence of soil-borne diseases such as bacterial wilt (Ralstonia Industry) solanacearum) and Phytophthora blight (Phytophthora capsici). An integrated crop management system consisting of grafted transplants, rain shelters, and resistant cultivars was developed to address this problem and increase sweet pepper production during the off-season. Oral Session 40: Pest Management In 2006 and 2007, sweet pepper grafted onto chili pepper rootstocks Thursday, 24 July 10:00 am–12:00 pm Salon 12 and grown under rain shelters and in the open field was evaluated for yield and the incidence of soil-borne diseases. In both seasons, the Moderator: Matt Kleinhenz, [email protected] incidence of bacterial wilt and Phytophthora blight was significantly (P < 0.05) reduced in grafted plants compared to non-grafted plants. 10:00–10:15 am Disease incidence was also lower under rain shelters than in the open field. Chili rootstock accessions 9852-62 and CO2548 provided better Efficacy of Organic Seed and Drench Treatments for disease resistance to grafted sweet pepper than 242-62 and the non- Control of Damping-off/Seedling Blight Pathogens of grafted control. Marketable yield was significantly (P < 0.05) higher Spinach in grafted sweet pepper, and cultivar Andulas consistently produced Jaime Cummings higher marketable yields than cultivars Blue Star, Hazera, and V20230 in both seasons. This study indicates the integration of grafting tech- Washington State University, Mount Vernon WA; jaime_ nology with rain shelters and improved disease-resistant cultivars [email protected] can lead to successful sweet pepper production during the off-season Lindsey du Toit* through the effective control of soil-borne diseases. Washington State University, Mount Vernon WA; [email protected] Specified Source(s) of Funding: Private (Association, Foundation, Carol Miles* Industry) Washington State University, Mt Vernon WA; [email protected] The demand for organically-produced seed has increased since 11:00–11:15 am implementation of the USDA National Organic Program. However, concern regarding losses to seedborne and soilborne pathogens has Bell Pepper Skin Separation (Silvering) Influenced by also increased because of the limited effectiveness of options currently Fertilizer Treatments available for seed treatments that satisfy organic standards. The ef- Wesley Kline* ficacy of a range of organic seed and drench treatments for control of Rutgers Cooperative Extension, Millville NJ; [email protected] soilborne seedling blight and damping-off pathogens of spinach was investigated to provide objective evaluation of EPA-registered products C. Andrew Wyenandt approved for use in organic systems, or products being developed Rutgers University, Bridgeton NJ; [email protected] for organic production. Spinach was used as a model small-seeded vegetable. Greenhouse inoculation rate trials were completed for each Daniel Ward of three soilborne pathogens, Fusarium oxysporum f. sp. spinaciae, Rutgers University, Bridgeton NJ; [email protected] Pythium ultimum, and Rhizoctonia solani. Fourteen seed and/or drench June Sudal treatments plus three control treatments were evaluated in greenhouse Rutgers University, Bridgeton NJ; [email protected] trials against each of the pathogens. For Pythium ultimum, two experimental seed treatments, Experimental #1 (a proprietary organic Silvering in bell pepper fruit has been consistently observed in disinfectant) and Experimental #2 (organic disinfectant + Trichoderma breeding lines and cultivars with tolerance to Phytophthora capsici harzianum T22), each provided equivalent control to that of a seed in New Jersey. The objectives of this research were to determine the treatment with the conventional fungicide Apron XL LS (mefenoxam); effects of fertilizer regimen and cultivar on the marketable yield and while Natural II and Natural X (actinomycete), and Subtilex (Bacillus incidence of silvering in bell pepper fruit. Two cultivars, Aristotle subtilis) seed treatments each suppressed damping-off significantly

1158 HORTSCIENCE, VOL. 43(4), JULY 2008 in one of two trials. For F. oxysporum f. sp. spinaciae, a compost tea The Ohio State University International Programs in Agriculture, The drench, Prestop (Gliocladium catenulatum) drench, and Yield Shield Ohio State University College of Food, Agricultural and Environmental (Bacillus pumilis) seed treatment each suppressed post-emergence wilt Science Federal Program Name, Award Number: Higher Education significantly in only one trial; but none of the treatments was highly Partnerships for African Development (HEPAD): Strengthening effective. For R. solani, Experimental #1 and Natural II seed treat- the Capacity of East African Faculties of Agriculture to Improve ments each reduced damping-off as effectively as a drench with the Smallholder Productivity, Kenya, Tanzania and Uganda. Developing conventional fungicide Terraclor (PCNB). The results demonstrated a a Regional Ipm Program for East Africa. 2005-2010. Integrated Pest number of organic products have potential for effective management Management Collaborative Research Support Project (Ipm CRSP). of damping-off of spinach. USAID Cooperative Agreement No.EPP-A-00-04-00016-00. Specified Source(s) of Funding: Department, College, State and/or HATCH Washington State University Center for Sustaining Agriculture and Natural Resources 10:30–10:45 am Plastic Film Mulches Affect Root Zone Temperature and the Manifestation of 10:15–10:30 am Tomato Spotted Wilt Symptoms and Yield in Tomato Seed Treatment and Mulch Effects on Seedborne Juan Diaz-Perez* Bacterial Pathogens and Yield of Tomato in Tanzania University of Georgia, Tifton GA; [email protected] Hosea Mtui Sokoine Ron Gitaitis University of Agriculture, Morogoro, Tanzania [email protected] University of Georgia, Tifton GA; [email protected] Amon P. Maerere Bikash Mandal Sokoine Univ. of Agriculture, Morogoro, Tanzania; [email protected] University of Georgia, Tifton GA; [email protected] Matthew Kleinhenz* Tomato spotted wilt (TSW) disease is a serious constraint to tomato The Ohio State University, OARDC, Wooster OH; [email protected] production in various regions of the world. The effect of TSW on Sally A. Miller tomato yield is largely influenced by time of infection. Early infection The Ohio State University-OARDC, Wooster OH; [email protected] usually results in severe stunting of the seedling and even death of the plant. Plastic film mulches affect both the incidence of TSW, and J. Mark Erbaugh plant growth and yield of tomato. The objective of the present study The Ohio State University, Columbus OH; [email protected] was to determine the effect of root zone temperature (RZT) as affected by plastic film mulch on the manifestation of symptoms of TSW, and Mark Bennett growth and yield of tomato plants either artificially inoculated with Ohio State University Columbus OH; [email protected] tomato spotted wilt virus (TSWV) or under natural TSW infection. In This project is part of larger overall efforts to: a) strengthen the artificially inoculated plants as well as in plants under natural TSW capacity of East African universities through innovative degree and infection, vegetative top fresh weight (FW) and fruit FW both increased non-degree training programs and b) develop Ipm systems for high with the length of time after transplanting that the plants remained free value horticultural crop production in East Africa. H.D. Mtui earned from TSW symptoms. The root zone temperature was highest under an MS from The OSU by completing coursework and exams in black mulch (seasonal mean = 27.5 °C), followed by gray (27.0 °C), Ohio and research in Tanzania. Field and lab studies were conducted silver (25.8 °C), and white (24.8 °C) mulches. The plants grown on to: i) assess the presence of seedborne bacteria in four different black mulch showed the earliest appearance of TSW symptoms, and tomato(Lycopersicon esculentum mill.) seedlots; and ii) evaluate the had significantly reduced vegetative growth and fruit yields compared efficacy of seed treatments and a 15-cm thick, Panicum spp.-based to plants on the other mulches. In conclusion, utilization of plastic dry grass mulch in reducing bacterial contamination and improving mulches that created conditions of high RZT stress resulted in reduced yield. The seedlots used were commercially available Cal J and Tanya plant growth and yield and predisposed the plants to earlier expression ORALS–THURSDAY and farmer-collected Tanya G1 and Tanya G2, the latter two being one of TSW symptoms compared to plants grown at RZTs more favorable and two generations removed from commercial lots, respectively. All to tomato plant growth (optimal RZT = 26.1 °C ). Since these plant lots were contaminated with Clavibacter michiganensis subsp. michi- responses to TSW under heat stress occurred in artificially inoculated ganensis (CMM), Xanthomonas spp. (XS) and Pseudomonas syringae plants as well as in plants under natural TSW infection, high RZTs pv. tomato (PST). Tanya G1, Tanya G2 and commercial Cal J seed probably affected the plants directly, independently of any possible were more highly contaminated with XS than commercial Tanya seed. effects on the thrips vectors. Tanya G2 seed had the highest PST contamination, but did not differ Specified Source(s) of Funding: Department, College, State and/or from other seed for CMM contamination. Chlorine and hot water seed HATCH Private (Association, Foundation, Industry) Industry/Associa- treatments significantly reduced bacterial populations on seed but treat- tion Program Name, Award Number: Ampacet Lewis Taylor Farms ment with Ridomil did not affect bacterial seed contamination levels. Average fruit yields were higher in commercial Tanya and Tanya G1 than in Cal J and Tanya G2. Seedlot did not influence the incidence of blossom end rot (BER) and fruit blemishes due to sunscald. Treating 10:45–11:00 am seed with chlorine or hot water led to a higher number of fruit per Use of Cultural and Chemical Practices to plant and yield per acre compared to no treatment or treatment with Reduce Tuber Damage from the Ridomil. While seed treatment did not affect the incidence of BER, Potato Tuberworm in the Columbia Basin sunscald was lower in plants produced from hot water treated seed than in control plants. Mulching plots increased fruit number per George Clough* plant, fruit weight and marketable yield and reduced the incidence of Oregon State University Hermiston OR; [email protected] sunscalding compared to not mulching plots. Sandra DeBano Specified Source(s) of Funding: Department, College, State and/or Oregon State University Hermiston OR; [email protected] HATCH Federal competitive Department of Horticulture and Crop Silvia Rondon Science, The Ohio State University Department of Plant Pathology, Oregon State University Hermiston OR; [email protected]

HORTSCIENCE, VOL. 43(4), JULY 2008 1159 Nicholas David rotundus) control has been inconsistent, in many cases due to a lack of North Dakota State University, Fargo ND; [email protected] knowledge about application techniques. Field studies were conducted to determine the effect of MK concentrations on purple nutsedge Philip Hamm control. Treatments were 0, 2000, 3000, 4000, 5000, and 6000 ppm Oregon State University, Hermiston OR; [email protected] of MK. There was a significant effect of MK concentrations obtained from a single application rate resulted in improved purple nutsedge Cultural practices and insecticide treatments and combinations were 2 evaluated for effect on tuber damage by potato tuberworm (PTW), control up to 10 WAT, reducing densities to less than 50 plants/m Phthorimaea operculella, in the Columbia basin of eastern Oregon with 6000 ppm of MK. and Washington. A range of intervals between initial application of Specified Source(s) of Funding: Private (Association, Foundation, several insecticides and vine-kill were tested to determine how early Industry) Industry/Association Program Name, Award Number: to implement a program to control PTW tuber damage. Esfenvalerate, Amvac methamidophos, and methomyl were applied at recommended intervals, with programs beginning 28 to 5 days prior to vine-kill. Indoxacarb was applied post vine-kill as a chemigation treatment. All insecticide 11:30–11:45 am treatments significantly reduced tuber damage as compared to the untreated control, but there was no apparent advantage to beginning Distribution and Persistence of Imidacloprid control efforts earlier than later in the season. Another study exam- in Ash Trees Following Trunk Injection: ined green foliage and increased soil moisture impact on PTW tuber Spring Versus Fall Injections damage. ‘Russet Norkotah’ and ‘Russet Burbank’ plants were allowed to naturally senesce or were chemically defoliated. They received Sara Tanis* either no irrigation or were irrigated by center-pivot with 0.25 cm Michigan State University, East Lansing; [email protected] water daily from vine-kill until harvest 2 weeks later. Tuber damage Bert Cregg was similar between varieties, but daily irrigation following vine-kill Michigan State University, East Lansing; [email protected] reduced tuber damage, and chemical vine-kill tended to reduce tuber damage as compared to natural senescence. Covering hills with soil David Mota-Sanchez provides good protection, but must be done at vine-kill. Rolling of Michigan State University, East Lansing; [email protected] potato hills in sandy soils may expose tubers and is not recommended Deb McCullough in this Columbia Basin area. Michigan State University, East Lansing; [email protected] Specified Source(s) of Funding: Private (Association, Foundation, Therese Poland Industry) USDA Forest Service East Lansing MI; [email protected] Robert Hollingworth 11:00–11:15 am Michigan State University, East Lansing; [email protected] Drip Tape Placement Affects Development of Raspberry Emerald Ash Borer (EAB, Agrilus planipennis Fairmaire, Coleop- Root Rot tera: Buprestidae) is a phloem boring exotic insect pest from Asia. It Thomas Walters* arrived in the; near Detroit, MI, in the late 1990s and was first identified in 2002. Since its arrival, it has killed over 25 million ash Washington State University, Mount Vernon WA; [email protected] (Fraxinus spp.) trees and is now found across six states and Canada. Michael Particka Trunk-injected applications of imidacloprid are an effective but Washington State University, Mount Vernon WA; [email protected] variable means of control for EAB. Trunk-injections are usually performed by arborists in either the spring or fall of the year. There is Under conditions of high root rot pressure from Phytophthora fragariae some evidence that a single application of imidacloprid can provide var. rubi (Pfr), above-ground symptoms of raspberry root rot in the two years of EAB control but the mechanism and overall length of moderately-susceptible cultivar ‘Meeker’ were determined by the control remains unknown. This experiment examined the difference placement of irrigation drip tape. Symptoms were most severe when in pesticide concentrations between trees injected during the spring the tape was directly above the crowns, and were less severe when tape and trees injected during the fall. The objectives of the study were was either buried or elevated but offset from the crowns. Soil matric to determine: 1) if fall trunk injections can provide adequate EAB potentials beneath the tape remained low for over 24 hours following control the following spring and; 2) if a single spring or fall trunk irrigation. These matric potentials stimulated Pfr sporangia formation injection can provide more than one season of EAB control. On June in laboratory studies. The Pfr-resistant cultivar Cascade Bounty did not 27, 2006, and September 5, 2006, we trunk-injected 32 trees and 8 show symptoms of root rot regardless of drip tape placement. trees, respectively, with 14Carbon labeled imidacloprid and Imicide Specified Source(s) of Funding: Private (Association, Foundation, imidacloprid. A single injection point was made either directly below Industry) Washington Red Raspberry Commission, and Washington or at a right angle to a branch in the first whorl. Each branch of the Commission on Pesticide Registration Industry/Association Program first three whorls was labeled 0 /180 or L90 /R90 (depending on the Name, Award Number: Washington Red Raspberry Commission, and location of the branch in relation to the injection point) and sampled Washington Commission on Pesticide Registration separately. Leaf samples of trees injected in both June and September were taken 21 days after treatment (DAT), and again in June 2007, during EAB peak flight. Imidacloprid equivalent concentration in leaves varied by injection date, sampling time, orientation to the injection 11:15–11:30 am point, and whorl height. Trees that were injected in June 2006, had Influence of Metam Potassium Concentrations on 25% to 50% residual imidacloprid equivalent concentration in 2007 Nutsedge Control in Mulched Beds when compared to 2006. Trees that were injected in September had Bielinski Santos* lower concentrations during the year of injection than trees that were injected in June. University of Florida, Wimauma FL; bmsantos@ufl.edu James Gilreath Specified Source(s) of Funding: Department, College, State and/or HATCH PhytoServices, Myakka City FL; bmsantos@ufl.edu The efficacy of metam potassium (MK) on purple nutsedge (Cyperus

1160 HORTSCIENCE, VOL. 43(4), JULY 2008 11:4–12:00 pm early in the chilling process and stored at 4 °C to provide additional New Strategies for the Chemical Control of Fire Blight chilling. The response curve was hyperbolic, with time to initial bud break declining from 4-5 weeks for minimally chilled buds, down Disease on Pears to 7-10 days for buds with extended chilling. It appeared that incre- Kubilay K. Bastas* mental chilling dramatically reduced heat unit requirement to bud Selcuk University Konya, Turkey [email protected] break when the shoots were under-chilled, but the effect diminished as buds received more chilling. As with naturally-chilled shoots, the Fire blight caused by Erwinia amylovora (Burr.) Winslow et al., is one percentage of bud break increased as chill increased, suggesting that of the most destructive diseases of pome fruits. Shoot blight phase of the buds on a single shoot have a wide range of chill requirements. This disease is more injurious on various hosts especially for overwinter response curve may be useful in developing a peach chilling model survival of the pathogen and secondary infections. In vitro and in vivo that better accounts for the transition between chilling accumulation conditions; the effectiveness of the plant growth regulator, prohexa- and heat accumulation. dione-Ca; the systemic acquired resistance (SAR) inducers, harpin protein, benzothiadiazole, as the bactericides; and copper salts of fatty Specified Source(s) of Funding: Federal competitive USDA Germplasm and rosin acids and streptomycin and fungicide mixture, maneb+copper Committee: Pecans were evaluated on the most susceptible host pear varieties that are grown extensively: ‘Ankara’; ‘Santa Maria’; ‘Williams’; ‘Deveci’; and ‘Riza Bey’. Application times of chemicals and inoculation of E. amylovora 10:45–11:00 am were based according to shoot lengths. Applicable possibilities and effects of used chemicals on disease severity and shoot growth in early Afterripening in Coreopsis lanceolata L. Seeds stages of growing season were also examined after inoculation with E. Dzingai Rukuni* amylovora for continuousness of protection. Streptomycin controlled University of Florida, Gainesville; drukuni@ufl.edu the shoot blight phase of fire blight around 95% and it was followed Jeffrey G. Norcini by harpin protein using four times on pear cv. Ankara reached about 58% and 72% effectiveness of the chemical in greenhouse and field, University of Florida Quincy FL; wldflowr@ufl.edu respectively. Prohexadione-Ca significantly reduced shoot lengths on Daniel J. Cantliffe pears. After benzothiadiazole and prohexadione-Ca applications, the University of Florida, Gainesville; djcant@ufl.edu severity of disease was reduced on shoots inoculated compared with copper compound, maneb+copper and untreated controls. Before and Seeds of the wildflower (Coreopsis lanceolata L.) have been reported after inoculations each two times applications of the chemicals gave to exhibit dormancy. Studies were conducted to identify factors better results than application of chemicals before inoculation two times. imposing dormancy. The effects of potassium nitrate, seed tissues The results indicated that quince cv. Ankara showed lower disease enveloping the embryo, gibberellic acid (GA4+7), temperature, af- severity than other pear cultivars. In the bioassay tests, firstly harpin terripening period (dry storage at 10 °C) and cold stratification were protein and then prohexadione-Ca, benzothiadiazole, were significantly investigated in the germination of freshly harvested seeds. Seeds were delayed the development of bacterial ooze at lower doses. Using of produced in a passively ventilated greenhouse, harvested, and bulked resistance inducing substances during the early phase of shoot growth over a 4 week period. After harvest they were dried to 8.1% moisture was offered in managing shoot blight phase of fire blight disease. content, sealed in a moisture-proof plastic bag and stored at 10 °C and 50% relative humidity in the dark. Seeds were taken at 14 day intervals for germination studies. In light, 1 and 10 mM potassium nitrate significantly increased germination from 38% to 49% and 54%, Oral Session 41: Cross-commodity Physiology respectively, but germination declined to 30% and 8% at 50 and 100 mM, respectively. Excised embryos germinated 100% in light after Thursday, 24 July 10:30 am–12:00 pm Salon 9 60 days of afterripening, whereas seeds without a pericarp achieved Moderator: W.R. Okie, [email protected] the same level in light after 90 days and germination of intact seeds was 99% after 150 days of dry storage. Germination increased as afterripening time increased; optimal temperatures being 15 °C and ORALS–THURSDAY 10:30–10:45 am 20 °C. A requirement for light to overcome dormancy was gradu- Interaction of Chill and Heat in ally lost with increasing afterripening duration. Dormancy was not Peach Flower Bud Dormancy overcome by GA in either light or darkness. Cold stratification led to a 50% reduction in germination in darkness. The results indicated William Okie* that potential dormancy imposed by the endosperm and pericarp was ARS-USDA, SEFTNRL Byron GA; [email protected] alleviated at 90 and 150 days of afterripening, respectively. Excised Bryan Blackburn embryos were virtually non-dormant. ARS-USDA, SEFTNRL Byron GA; [email protected] Specified Source(s) of Funding: Department, College, State and/or Peach bud dormancy requirement is a critical factor in selecting adapted HATCH cultivars, but the dormancy process is not well-understood. The Utah model proposes bloom occurs after a cultivar-specific amount of chilling followed by 5000 heat units above 4 °C. This model works well 11:00–11:15 am in colder climates, but is difficult to apply in moderate climates where Some Factors Affecting Carrot Seed Germination at High chilling is interspersed with extended warm spells. Observations over Temperature 5 years on orchard shoots (‘Flordaprince’, ‘Flordadawn’, ‘Flordaking’, Warley Nascimento ‘Juneprince’, ‘Sunland’, ‘Redglobe’, ‘Cresthaven’, and ‘Contender’) cut at weekly intervals consistently showed that as the field chilling Embrapa Vegetables Brasilia, DF, Brazil; [email protected] increased, percentage of flower buds able to break increased while Roseane Pereira time to bud break (days at 18 °C) decreased. No bud break occurred Embrapa Vegetables Brasilia, DF, Brazil; [email protected] if shoots were more than about 150 chill units below their standard chill requirement. However these results are confounded by the ef- Jairo Vieira fects of heat during the chilling process and vice versa. We studied Embrapa Vegetables Brasilia, DF; Brazil [email protected] the response (18 °C days to greeneye stage) of 40 cm long excised Daniel Cantliffe* shoots (‘Juneprince’, ‘Goldprince’, ‘Redglobe’, and ‘Blazeprince’) cut University of Florida, Gainesville; djcant@ufl.edu

HORTSCIENCE, VOL. 43(4), JULY 2008 1161 Carrot seed germination and, consequently stand establishment, may was slow and continual over a period of days to weeks, most likely due be reduced under temperatures above 35 °C. Studies on carrot seed to de-adsorption from media components. (S)-ABA exposure intervals germination at high temperature in response to genotype, umbel order, were 7.5 min, 15 min, 30 min, 1 hr, 2 hr, and 4 hr. Transpiration rate seed maturation, seed vigor, and priming were performed to determine was measured at 4 hr, 24 hr, and 48 hr after application (HAT) using potential germplasm and/or conditions that led to improved germi- a steady-state porometer. At 4 HAT, all exposure intervals resulted in nation at 35 °C. Seeds from 34 commercial cultivars and 125 carrot transpiration rates between 0.38 and 0.43 compared with 8.73 µmol·m- accessions were germinated at 25 °C (optimal) and 35 °C (high) in 2·s-1 for the control. At 24 and 48 HAT, exposure of 7.5 min resulted constant light. Also, seeds from 120 half-sib families from a ‘Bras lia in transpiration rates of 4.43 and 5.49 while exposure of 1 hr resulted ‘ carrot population were evaluated under the same conditions. In other in transpiration rates of 2.51 and 3.59, compared to transpiration rates studies, seeds from primary, secondary, and tertiary umbels were har- of 12.35 and 13.14 µmol·m-2·s-1 for the control. The (S)-ABA uptake vested separately, and also seeds from three different vigor levels (lots was rapid over a period of minutes by movement in the transpiration from 1998, 1999, and 2000) were tested for germination at 20 °C and stream. Differences in efficacy between exposure intervals and across 35 °C. Seeds harvested at different maturation periods [(20, 30, and time were probably due to metabolism. 40 days after anthesis (DAA)] and primed in an aerated PEG solution (30%) at 15 °C for 0, 3, 6, and 9 days, under light, were also evaluated in both germination temperatures. In all studies, high temperatures 11:30–11:45 am (35 °C) decreased carrot seed germination. Many of the commercial cultivars had reduced germination at 35 °C;’XPC-3617’, ‘Alvorada’, ABA Drenches Can Increase the Shelf Life of ‘Brasilia’,and ‘Esplanada’, had the greatest germination at 35 °C. The Salvia splendens accession PI 319858 germinated 95% in both temperatures and was Jongyun Kim* considered as thermotolerant. The 120 half-sib families of ‘Brasilia’ The University of Georgia, Athens GA; [email protected] had good germination and vigor at 20 °C; however, at 35 °C, only a few families germinated above 60%. Seeds from primary and secondary Marc van Iersel umbels had greater vigor and germination at high temperature than University of Georgia, Athens GA; [email protected] seeds from tertiary umbels. High vigor seed lots germinated better at Jong-Goo Kang 35 °C than low vigor seed lots. At 20 °C, unprimed seeds from umbels Sunchon National University, Sunchon, Korea [email protected] harvested after 20, 30, and 40 DAA germinated 88%, 95%, and 95%, respectively, while at 35 °C, seeds germinated only 4%, 13%, and 28%, Post-production care of bedding plants in retail centers is often poor respectively. Seeds from umbels harvested after 40 DAA and primed and a lack of adequate watering may reduce the shelf life of the plants. for 9 days germinated 98% and 89% at 20 °C and 35 °C, respectively. Using ABA applications to close the stomates and reduce plant water Selection of superior thermotolerant genotypes, as well as the use of loss can potentially extend the shelf life of bedding plants. To test this seed priming and/or other cultural practices during seed production hypothesis, we conducted two studies to quantify the effects of ABA may help circumvent carrot thermoinhibition problems. on water use and shelf life. In the first study, 50 mL of ABA solution was applied as a drench to Salvia splendens ‘Bonfire’ at concentrations Specified Source(s) of Funding: Federal competitive of 0, 250, 500, 1000, and 2000 mg·L-1. Plants were not watered after this initial drench. The substrate volumetric water content (VWC) was monitored continuously with soil moisture sensors and the stomatal 11:15–11:30 am conductance and transpiration rate were measured for 10 days. On the Determining Uptake of Paclobutrazol and (S)-Abscisic 3rd day after the ABA application, VWC in the control was less than 3 -3 Acid using a Split-root System Model 0.10 m ·m , whereas the substrate in ABA treatments still contained 0.24, 0.31, 0.44, and 0.47 m3·m-3 water at ABA concentrations from Jessica Boldt* 250 to 2000 mg·L-1. ABA application decreased stomatal conduc- University of Florida, Gainesville; jlboldt@ufl.edu tance from 166 mmol·m-2·s-1 in the control to 18 mmol·m-2·s-1 in the -1 James Barrett 2000 mg·L treatment within 3 hours after the application. Control University of Florida, Gainesville; jbarrett@ufl.edu plants started wilting just one day after the application, whereas 2000 mg·L-1 ABA treatments delayed wilting by 5 days. A negative side Paul Fisher effect of the ABA applications was leaf abscission, which increased University of Florida Gainesville FL United States; pfisher@ufl.edu with increasing ABA concentrations. ABA concentrations of 2000 mg·L-1 resulted in the abscission of 40 leaves/plant after 6 days. In James Gibson the second experiment, 10 different concentrations, ranging from Conrad Fafard, Inc. Anderson SC; [email protected] 8 to 1000 mg·L-1 were applied to S. splendens ‘Vista red’. Even an Gregory MacDonald 8 mg·L-1ABA drench delayed complete wilting by one day. No leaf University of Florida, Gainesville; pineacre@ufl.edu abscission occurred in the second study. Overall, ABA concentrations below 1000 mg·L-1 increased the shelf life of salvia without major Studies evaluating chemical uptake typically use labeled material and negative effects. Drenches with ABA can extend the shelf life of salvia results are determined using radiography or isolation and extraction in retail centers where effective water management is difficult. procedures. In a model system using Chrysanthemum × morifolium ‘Snowmass’, the root system was separated and grown in two adjoin- Specified Source(s) of Funding: Department, College, State and/or ing compartments of a cell pack. The chemical being evaluated was HATCH applied to one-half of the root system, which was then excised at different time intervals to stop exposure, and uptake was determined by changes in plant response between time intervals. Two plant growth 11:45–12:00 pm regulators, paclobutrazol {(±)-(R*,R*)β-[(4-chlorophenyl)methyl]- Tolerance of Several Sedum spp. to Various Ratios of α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol)} and (S)-abscisic acid [S-5-(1-hydroxy-2,6,6-trimethyl-4-oxo-2-cyclohexen-1-yl)-3- Crumb Rubber Amendments in Green Roof Expanded methyl-2,4-pentadienoic acid], were evaluated. Paclobutrazol exposure Shale Substrate intervals were 1, 2, 4, 8, 12, and 24 days. Stem elongation data were Lorelly Solano* recorded on day 24 and maximum inhibition of 55% was achieved University of Maryland College Park MD; [email protected] after 24 days exposure. Regression analysis was significant for the quadratic equation stem elongation (cm) = 0.96096 – 0.39878x + Andrew Ristvey* 0.00072x2, where x is exposure interval in days. Paclobutrazol uptake University of Maryland Queenstown MD; [email protected]

1162 HORTSCIENCE, VOL. 43(4), JULY 2008 Jennifer Himmelstein assists in the development of higher level thinking in students, team University of Maryland, College Park MD; [email protected] building skills, and situational analysis skills. While cases are routine in business and agribusiness classes, their use occurs less often in Steve Cohan other agriculture disciplines. Case study solutions require a different University of Maryland, College Park MD; [email protected] approach than traditional learning exercises in that several right an- John Lea-Cox swers may exist. This ambiguity challenges students. The true power University of Maryland, College Park MD; [email protected] of the case study method is evident when former students easily meet decision-making challenges because of the experience gained Recently, there has been increased interest in green roofs becoming a in preparing case solutions. The infrequent use of cases in agriculture part of American cityscapes, primarily to mitigate storm water runoff classrooms extends beyond national boundaries because instructors from impervious surfaces in dense urban areas. Extensive green roofs are unfamiliar with the development and use of case studies. Cases are functional, increasing stormwater retention by incorporating a thin are an opportunity for student, faculty, and agribusiness interaction. layer of substrate (approximately 10 cm) with specific roof liners and Case success is dependent upon proper analysis, planning, attention planted with xerophytic species which are tolerant of large diurnal and to detail, evaluation, and implementation. In 2006 and 2007, faculty seasonal temperature fluctuations. Soon, new city buildings may be members from Egyptian and American universities collaborated to required to have systems in place for greater stormwater retention, yet develop interdisciplinary case studies of Egyptian agribusinesses. in some cases, city planners will be asked to retrofit extensive green The”Train the Trainer “ workshops used in the development of these roofs on older structures. The substrates presently used in extensive cases proved to be a powerful set of training tools for faculty members. green roof designs consist primarily of light-weight heat expanded This case development resulted in interdisciplinary collaboration, shales, clays and slates. Physical and chemical processes may result improved relations with industry, training of other Egyptian faculty, in the degradation of these particles over time, reducing aeration and and the development of seven cases. We will discuss the processes, increasing the potential for waterlogging, whereby causing reductions challenges, and solutions experienced during case development for in plant health with a consequent increase in maintenance and renova- Egyptian undergraduate classrooms. tion costs. We therefore seek to investigate the addition of a potentially stable, recycled tire product (crumb rubber) to these substrates, to Specified Source(s) of Funding: Federal competitive MUCIA Coop- increase their long-term performance and sustainability. At the same erative Agreement for Institutional Linkages Activity - Agricultural time crumb rubber would decrease the weight of the substrate and Exports and Rural Incomes (AERI) RFA #263-P -03-002/USAID/ increase the percentage of buildings able for retrofit of extensive green Egypt. Federal Program Name, Award Number: RFA #263-P -03- roof systems. However, crumb rubber has been shown to leach quanti- 002/USAID/Egypt ties of zinc that affect growth of sensitive plants. At the same time, it is known that the genus Sedum, which is widely used for extensive green roofs, includes one species that can hyperaccumulate zinc. This research studied the growth of three Sedum species in expanded shale 11:30–11:45 am substrate with incremental rates of incorporated crumb rubber, the goal being to find the highest ratio of crumb rubber amendment tolerated Exchange of Culture: Thailand Exploration by several Sedum species. Brian Trader* Specified Source(s) of Funding: Department, College, State and/or Mississippi State University; [email protected] HATCH Private (Association, Foundation, Industry) Study abroad opens the minds of students to diverse cultures, foreign tastes, and exotic flora. The opportunity to study abroad allows students to learn based on experience, relationship, interaction, and choice. On Dec. 12, 2007, eight students and the author embarked on a three-week tour of Thailand. The experience in Thailand was designed to expose Oral Session 42: students to Asian culture using an interdisciplinary approach. The

course allowed students from different backgrounds, matriculating ORALS–THURSDAY Teaching Methods: Outside the Classroom Learning in different subjects to converge in a foreign setting and share in a Thursday, 24 July 11:15 am–12:00 pm Salon 8 unique learning opportunity. The course was organized in collaboration with Maejo University in Thailand, and fostered interaction with Moderator: Brian W. Trader, [email protected] Thai faculty and students. The emphasis was agricultural, however other topics including history, ecology, business, architecture, politi- cal science, geology, natural resources, and textiles were also areas 11:15–11:30 am of interest and focus. Overall, the course was a huge success. The International Case Studies: Capacity Building for students were required to maintain daily journals throughout the dura- Undergraduate Education tion of the study abroad program. It was enlightening to see how the Daniel F. Warnock viewpoints change among the students from first step into Thailand until the return flight to the United States. The students walked away University of Illinois, Urbana; [email protected] with a life-changing experience. One student had never even flown Roger Natzke on a plane before. In their final papers, students discussed varied top- University of Florida, Gainesville; [email protected]fl.edu ics ranging from prostitution and adoption to agriculture and natural resource renewal. Feedback from student participants was positive. David Hahn Watching the development and the influence of this course in the ac- Ohio State University Columbus OH; [email protected] tions and personalities of the students was truly rewarding. Equally Experience shows that case studies bring an exciting dimension rewarding was how well the Thai people welcomed our small delega- to classrooms. The development of cases can be a challenging but tion. Our guides and the faculty and students of Maejo University also rewarding opportunity. Cases present a realistic and meaningful learned during this cultural exchange. The excursion to Thailand has experience based on real world data to students. Agribusiness man- renewed opportunities for faculty and student exchange between the agers make decisions that directly influence future revenues, costs, two universities and paved the way for future collaboration. and profits of the firm. Thus, a student’s academic training must be Specified Source(s) of Funding: Department, College, State and/or applicable to agribusiness problem solving. The case study method HATCH

HORTSCIENCE, VOL. 43(4), JULY 2008 1163 11:45–12:00 pm where techniques are different, EMS often require more labor. Insect One Potential Model for Required Internships Backed by pest control is the exception. Where techniques are similar, labor requirements will likely not differ. No SQ indicator or efficiency Employer Satisfaction Survey was significantly affected by management regime. Thus, in most Terry Ferriss* respects, ecological sustainability did not change with management. University of Wisconsin–River FallsI; [email protected] This contrasts with most studies to date. Yield was also unaffected by management regime, indicating that EMS do not necessarily yield less. Internship experiences have become an integral part of the undergradu- Given results, neither agroecosystem seems to be more sustainable. ate academic curriculum. Required internships benefit the student and Similar inputs between EMS and CMS may explain this. the academic programs. Students connect real world experience to classroom content; gain technical, business and communication skills; Specified Source(s) of Funding: Private (Association, Foundation, develop professional networks; assess career options; earn wages to Industry) Compton Foundation Tropical Environment and Sustain- help fund future tuition; and demonstrate leadership capabilities and ability Fellowship critical thinking skills. The campus-based faculty coordinators build industry connections; gain first-hand exposure to current industry issues and needs; obtain feedback related to the content of the curriculum 2:15–2:30 pm that is preparing students for the industry; and assess student ability to translate theory into practice. The College of Agriculture, Food and Evaluation of Brassica Cover Crops as Potential Environmental Sciences at the University of Wisconsin River Falls has Alternative to Methyl Bromide for Eggplant Production implemented a model for required student internships. Key compo- Mathieu Ngouajio* nents include: the development of learning objectives; student weekly Michigan State University, East Lansing; [email protected] reports; a special student project completed as part of the internship; employer evaluations; student evaluations of the employer and of the Mary K. Hausbeck program; and faculty coordinator on-site visits. Faculty are financially Michigan State University, East Lansing; [email protected] supported for their involvement in the program as they would be sup- Ronald G. Goldy ported for teaching other parts of the curriculum. A 2007 survey of Michigan State University Benton Harbor MI; [email protected] participating employers revealed strong employer satisfaction with the program. Additional details of the program structure and survey James W. Counts, Jr. results will be discussed. Michigan State University, East Lansing; [email protected] Specified Source(s) of Funding: Department, College, State and/or With the phase-out of methyl bromide, commercial eggplant (Solanum HATCH melongena) growers who have traditionally relied on fumigation to maintain acceptable yields are currently interested in effective alternative strategies to remain competitive. Brassica cover crops produce isothiocyanates upon tissue breakdown that are similar to active Oral Session 43: Sustainable Production compounds found in some commercial fumigants, and therefore, could be used as biofumigants in an eggplant production system. Thursday, 24 July 2:00–3:30 pm Salon 8 Field experiments were conducted in 2007 at the Michigan State Moderator: Alvaro Valle Valenzuela, chevalle@ufl.edu University Southwest Research and Extension Center to compare eggplant performance when using various Brassica cover crops and methyl bromide fumigation. The cover crop treatments were oilseed 2:00–2:15 pm radish (Raphanus sativus ‘Defender’), yellow mustard (Sinapis alba Labor, Soil Quality, and Yield in Ecological and ‘Tilney’), and oriental mustard (Brassica juncea ‘Forge’) at 20, 9, Conventional Small-scale, Tropical Agroecosystems and 8 Lb/A, respectively. Methyl bromide (67/33% methyl bromide chloropicrin) was applied at 350 Lb/A under black plastic mulch. Alvaro Valle* Eggplant yields were highest with the methyl bromide treatment (666 Valenzuela University of Florida, Gainesville; chevalle@ufl.edu bushels/A) and lowest with the untreated control (427 bushels/A). Ideally, sustainable management of small-scale systems in the devel- All cover crop yields fell between the methyl bromide standard and oping tropics would simultaneously lower labor inputs, increase soil the untreated control. The cover crops showed potential to reduce quality (SQ), and increase yields. Whether ecological management Verticillium wilt and improve eggplant yield, but their performance systems (EMS) or conventional management systems (CMS) are more did not match methyl bromide for disease suppression and crop yield. sustainable in this context was studied. A cross-sectional design with Therefore, the cover crops should be used as a component of integrated referral sampling was used during June-Aug. 2006 in Leon, Nica- management strategies. ragua, to answer this question. All replicates were <7 hectares and Specified Source(s) of Funding: Federal competitive Federal Program planted late- season Sesamum indicum L. on sandy-loam andisols. Name, Award Number: USDA Methyl Bromide Transition Labor and labor productivity, SQ and SQ efficiency, and Sesamum yield were measured. A management index identified the approach to overall agroecosystem management on a scale from conventional to ecological. A semi-structured interview was used to gather labor 2:30–2:45 pm and yield data. Soil sampling and indicator analysis measured SQ. Impacts of Double-line Drip Irrigation and Straw The SQ indicators included percentage of organic matter, acidity, Mulching on Sweet Cherry Water Use and Productivity phosphorus availability, biotic activity, and bulk density. Statistical Xinhua Yin* tests include t-tests and Mann-Whitney. Total labor was unaffected by management approach, nor was labor productivity. Labor amounts University of Tennessee Jackson TN; [email protected] (man-days/manzana) differed significantly only for fertilization Clark Seavert (P < 0.05) and disease control (P < 0.10) practices, with EMS being Oregon State University Hood River OR; [email protected] more labor intensive. Conventional farmers allotted greater proportions of their labor to weed (P < 0.10) and insect pest (P < 0.10) control Nick Tomasini than did ecological farmers. Labor productivity was not different Oregon State University Hood River OR; [email protected] between treatments for any practice or in totality, though very small Irrigation water and ground management are two key management sample sizes lowers confidence in these results. Results indicate that practices in sweet cherry production in Oregon and the Pacific North-

1164 HORTSCIENCE, VOL. 43(4), JULY 2008 west. This project was designed to evaluate the impacts of converting rate of 6 g CRF. We conclude that inoculated CRF-treated plants of A. micro sprinkler irrigation into double-line drip irrigation, the effects maritima can form nodules, and that these plants maintain acceptable of changing no ground cover to straw mulch ground cover, and their growth and N-status at CRF levels lower than that prescribed. interactions on water use, fruit yield, quality, and storability of sweet cherry, plant nutrition, and soil quality. A field experiment was con- Specified Source(s) of Funding: Federal competitive Center for Water ducted on the Omeg Orchards at The Dalles, OR, in 2006 and 2007. Efficient Landscaping, Utah Botanical Centers & Utah Ag. Exp. Sta. Two irrigation systems (double-line drip irrigation, micro-sprinkler #375 irrigation) and two ground management systems [straw mulch, control (no ground cover, but herbicides were used to control weeds)] were evaluated in a split-plot design with four replicates. The two-year 3:00–3:15 pm results showed that double-line drip irrigation saved 50% to 57% ir- Effect of Drip Irrigation System Operating Pressure on rigation water compared with micro-sprinkler irrigation each season. Flow Rate and Uniformity of Water Application Straw mulch reduced irrigation water use by 5% to 16% relative to no cover each year. Fruit yields were similar for double-line drip irrigation Aparna Gazula* and micro sprinkler irrigation. However, there was a trend of yield University of Florida, Gainesville; virgoinc@ufl.edu increase with straw mulch. Fruit quality including fruit size, firmness, Eric Simonne color, titratable acidity, and sugar content did not differ significantly University of Florida, Gainesville; [email protected]fl.edu regardless of irrigation and ground cover system. Double-line drip irrigation showed a tendency of increasing the percentage of market- Robert Hochmuth able fruit by reducing fruit surface pitting and bruising compared with University of Florida, Live Oak; bobhoch@ufl.edu micro-sprinkler irrigation. Straw mulch seemed to enhance the electric conductivity and populations of active bacteria and fungi in the soil. Increasing lateral water movement as an attempt to reduce vertical Overall, double-line drip irrigation has the potential to significantly water movement may help reduce nutrient loss below the root zone of reduce sweet cherry water use while maintaining compatible productiv- vegetables grown with plasticulture. While it is believed that lateral ity relative to micro sprinkler irrigation. Straw mulch not only reduces movement of water may be increased with reduced operating pres- irrigation water use, but also eliminates herbicide applications and sure, changing the operating pressure may affect drip tape (DT) flow improves soil quality compared with no ground cover. rate and uniformity of water application. The effect of combinations of three commercial DT (30.5-cm emitter spacing; with 248 (DT1), Specified Source(s) of Funding: Department, College, State and/or 298 (DT2), 484 (DT3) L/100 m/hr flow rate at 84 kPa) and two op- HATCH Private (Association, Foundation, Industry) Federal com- erating pressures (84 and 42 kPa) on actual flow rate and uniformity petitive Oregon State Unversity Agricultural Research Foundation of water application was assessed on a flat Blanton-Foxworth-Alpin Industry/Association Program Name, Award Number: Oregon Sweet fine sand soil complex. Treatments were replicated four times, and Cherry Commission Federal Program Name, Award Number: USDA the length of the laterals was 91 m each. Desired operating pressures NRCS Conservation Innovation Grant, 68-3A75-6-130 were achieved by using two pressure regulators (42 and 84 kPa with 15-61 and 8-76 L/min. flow rates, respectively). Uniformity of water application (Us) was calculated as Us = 100 × (1 - Vqs), where Vqs 2:45–3:00 pm = statistical coefficient of variation of emitter discharge rates, and was rated “unacceptable” (Us < 60%), “poor” (60% to 70%), “fair” Nodulation of Seaside Alder Topdressed with Controlled (70% to 80%), “good” (80% to 90%), or “excellent” (Us >90%). Release Fertilizer Flow rate was measured from two emitters at six different lengths on Taun Beddes each lateral. Mean flow rate was significantly higher at 84 than at 42 Utah State University Logan UT; [email protected] kPa operating pressure (298 and 224 L/100 m/hr, respectively). Us was also affected by operating pressure. At 84 kPa, Us was “good” Heidi Kratsch for DT2 (83.1%) and DT3 (80.3%), whereas Us was “poor” for DT1 Utah State University Logan UT; [email protected] (60.6%). At 42 kPa, Us was “poor” for DT1 (63.1%) and DT3 (69.9%), ORALS–THURSDAY Alnus maritima (seaside alder) is a rare species adapted to ornamental and Us was “unacceptable” for DT2 (52.1%). A slight increase in Us landscape use. It can be easily produced by commercial growers and at the 42 kPa operating pressure was observed with DT1. However, when soil-inoculated in nursery containers, will form root nodules DT2 and DT3 showed an unacceptable reduction in uniformity of containing N-fixing Frankia bacteria. Nodulated N-fixing plants water application suggesting that growers should be aware of their may better adapt to landscape situations as a result of their enhanced DT response to operating pressure (level of pressure compensation). ability to grow in nutrient-poor soils. It was demonstrated previously Hence, reducing operating pressure from 84 to 42 kPa as an attempt that nodulation within this species can be controlled by the amount to increase lateral movement of water in the soil may reduce Us to of N plants receive from a liquid source. However, controlled release an unacceptable level. fertilizers (CRF) are more commonly used by commercial growers Specified Source(s) of Funding: Federal competitive and nutrient-release rates from these products can be highly variable. Our objectives were to determine if greenhouse-grown inoculated plants treated with CRF will form nodules, and what level of CRF 3:15–3:30 pm maximizes nodule formation while sustaining acceptable plant health and growth. Plants were grown in a substrate containing 1 Sphagnum Developing Decision Tools to Assess Water and Nutrient peat moss : 1 perlite (by volume). On 14 Aug. 2007, inoculated plants Runoff from Ornamental Operations in Maryland were arranged in a randomized complete-block design and topdressed John Majsztrik* with CRF at 0, 0.5, 1, 2, 4, 8, 16, and 32 g by weight. An additional University of Maryland, College Park; [email protected] treatment was irrigated twice daily with 250 ml of a complete nutrient solution containing 8 mM NH4NO3, and a group of uninoculated John D. Lea-Cox plants received the prescribed rate of 6 g CRF. All CRF-treated plants University of Maryland, College Park; [email protected] were irrigated twice daily with 250 ml tap water. On 25 Sept, 2007, Andrew G. Ristvey all plants were destructively harvested. We found that treatment with 2 g CRF maximized root nodule formation (21 nodules; 8.8 mg dry University of Maryland, Queenstown; [email protected] weight), and that plant growth parameters and leaf N content of these David S. Ross plants were similar (P < 0.05) to those of plants receiving the prescribed University of Maryland, College Park; [email protected]

HORTSCIENCE, VOL. 43(4), JULY 2008 1165 The Chesapeake Bay watershed is 64,000 square miles and collects academic mission, to rethink the “land-grant” mission of agriculture water from six states in the Mid-Atlantic region and the District of education. Findings of the summit and follow-up workshop will be Columbia. Nutrient and sediment runoff into the watershed has caused presented and discussed in a horticultural context. Suggestions for the Bay’s health to decline and continues to impact its long-term sus- involvement of ASHS through its membership and its leadership will tainability. Much of the research on nitrogen (N), phosphorous (P), and be presented. sediment loading into this watershed has focused on reducing point sources and non-point sources from traditional farms, with minimal Specified Source(s) of Funding: Department, College, State and/or research focusing on ornamental nursery and greenhouse operations. HATCH There are about 500 of these operations in Maryland, which contain 15% of the irrigated land, often combined with high nutrient applications, since plant densities are often extremely high. The Maryland 2:15–2:30 pm Department of Agriculture requires every registered nursery and green- Skills Needed to Start Horticultural Careers house operation in Maryland to submit a detailed water and nutrient Ron Larson* management plan, which identifies among other things, the number of plants produced, production area, and yearly N and P application Western Michigan University, Kalamazoo MI; [email protected] rates to that area. We have developed a GIS database that aggregates One option to enhance college curricula is to ask professionals what nutrient application data at the 12-digit watershed level, to examine skills they perceive to be most important. Most prior surveys on total nutrient applications by land use and proximity to surface water, horticultural skill needs focused either on a particular specialization in an effort to predict where nutrient runoff potentials are highest. or on technical skills within the field. This study asked horticul- Decision management tools are currently being developed to assess tural practitioners in the Midwest what technical skills, computer potential runoff from greenhouse, field, and container-nursery opera- information and data skills, previous experiences, communication tions, based on inputs and management, to identify the best mix of skills, business and economics skills, and interpersonal character- management practices that will reduce water and nutrient runoff, yet istics would be most important for starting a career. More than 175 maintain plant health and profitability. This will help target cost-share usable responses were received (about 35% from landscape design monies for improvements, promote the long-term sustainability of this and management, 28% from wholesale plant and flower production, sector of agriculture and work toward meeting the goals of the 2010 and 25% from retail nursery or floral). Respondents rated skills on a Chesapeake Bay agreement. 7-point scale with 7 being critically important and 1 being not impor- Specified Source(s) of Funding: Department, College, State and/or tant. The interpersonal characteristics group contained 18 traits and HATCH had the highest average. The communication skills group was second highest. In the business and economics skills group, “identification of customer needs and wants” and “identify firm objectives and goals” had averages exceeding 5.5. In the computer, information and data Oral Session 44: Teaching Methods—Assessment skills group, only “use of the internet” had an average exceeding 5.5. None of the previous experience group items had averages exceeding Thursday, 24 July 2:00–3:15 pm Salon 9 5.0. The technical skills group contained 36 items. “Plant identification and nomenclature,” “plant disease identification and control options,” Moderator: Ron Larson, [email protected] “insect identification and control options,” and “water/moisture management” had averages exceeding 5.5. People from different areas 2:00–2:15 pm rated skills differently, suggesting that specialized courses for specific Is there a Quiet Crisis Developing in careers are needed. Eleven technical skills and eleven business and economics skills had averages exceeding 4.5. Covering these busi- Horticulture Higher Education? A Role for ness and economics skills in a curriculum may require adding courses ASHS Members to Help in Setting a including a capstone course focused on horticultural business issues National Agriculture Higher Education Agenda using industry case studies. Curt Rom* Specified Source(s) of Funding: Department, College, State and/or University of Arkansas, Fayetteville; [email protected] HATCH Private (Association, Foundation, Industry) University of Dr. Shirley Jackson has presented the idea that a “perfect storm “ has Florida/IFAS Industry/Association Program Name, Award Number: been brewing with the greying of the American scientific commu- Florida Nursery, Growers and Landscape Association Southwest nity and a lack of well-trained scientists, and educational programs Florida Water Management District preparing scientists to replace them. This is leading to what she has called a “Quiet Crisis” in science and technology education in the U.S., ultimately leading to lack of international competitiveness. 2:30–2:45 pm At congressional request, the National Academy of Sciences (NAS) Use of Rubrics in Horticulture Laboratory Courses studied U.S. global competitiveness. In the NAS report, “Rising Kimberly Moore* Above the Gathering Storm,” there are forecast problems in training and retaining the best and the brightest in sciences and technology. A University of Florida, Davie; klock@ufl.edu recommendation from the NAS in the “Storm “ publication suggested Students enrolled in horticulture curricula around the country are often that the U.S. develop a more attractive setting in which to study and concerned about how they will be graded especially in laboratories perform research and development in universities in order to recruit where they will be expected to write laboratory reports. Many profes- and retain the best students. The Board of Agriculture and Natural sors use checklists of criteria that they are looking for in laboratory Resources under the aegis of the NAS held a “Leadership Summit reports. However, checklists do not describe the desirable qualities or to Effect Change in Teaching and Learning Agriculture Science” in common pitfalls students encounter. Rubrics are tools that list criteria Oct. 2006, with a regional follow-up workshop in June 2007. Summit for a piece of work as well as delineate how the work is assessed. goals were to enhance excellence in higher education, increase col- The assessment is grounded in a list of desired outcomes (qualities) laborative and integrative efforts of education and research, increase that provide specific targets for the student to achieve. However, for communication among the scientific professions, to foster integration rubrics to be successful, they must be shared with the student. This of teaching, research and outreach, and to set a national agenda for presentation will share several rubrics used in horticulture laboratory higher education in academic programs in agriculture and the life sci- courses taught at the University of Florida, Fort Lauderdale, teach- ences. This leadership summit was a call to arms to think about a new ing program.

1166 HORTSCIENCE, VOL. 43(4), JULY 2008 Specified Source(s) of Funding: Department, College, State and/or to assure institutional conformity to specified norms. HATCH Private (Association, Foundation, Industry) Specified Source(s) of Funding: Department, College, State and/or HATCH 2:45–3:00 pm Curriculum Evaluation: An Outcomes Assessment of the Department of Horticulture at Iowa State University Oral Session 45: Postharvest Physiology Elizabeth Duncan* Thursday, 24 July 2:00–3:30 pm Salon 7 Iowa State University, Ames; [email protected] Moderator: Thomas L. Davenport, tldav@ufl.edu Ann Marie VanDerZanden Iowa State University, Ames; [email protected] 2:00–2:15 pm Cynthia Haynes Bio-based Containers and 2E-hexenal: Commercial and Iowa State University, Ames; [email protected] Environmental Benefits to Prolong Blueberry Shelf Life Levon Esters Eva Almenar* Iowa State University, Ames; [email protected] Michigan State University, East Lansing; [email protected] The Iowa State University undergraduate horticulture program has Rafael Auras been nationally ranked as one of the best by the Gourman Report. Michigan State University, East Lansing; [email protected] Regular and systematic outcomes assessment is one means to evaluate the program for purposes of sustaining this level of ex- Hayati Samsudin cellence. The purpose of this study was to conduct a survey of Michigan State University, East Lansing; [email protected] horticulture graduates to determine preparedness when entering the Maria Rubino workforce, departmental effectiveness, and to evaluate how well Michigan State University, East Lansing; [email protected] graduates met departmental learner outcomes. A 59-question survey instrument was distributed electronically to a proportional sample of Bruce Harte 339 horticulture alumni who graduated between 2000 and 2006. The Michigan State University, East Lansing; [email protected] response rate was 48%. Results showed that graduates found jobs quickly, and a majority (76.7%) noted that their first and current jobs The blueberry industry contributes significantly to the American were highly related to their degree. Further, 41.8% rated themselves economy since the U.S. is by far the leading producer of these fruits as adequately prepared, 37.9% more than adequately prepared, and in the world. Domestic and export demands of this fruit are expected 15.5% exceptionally well prepared for their first job. Respondents also to grow in response increasing consumer demand due to the clinical ranked their abilities related to the 33 learner outcomes questions as evidence supporting the health benefits of berry consumption. Storage good to excellent. conditions, which slow down aging and prevent decay due to pathogen attack, are highly desirable. Packaging technologies, such as equilib- Specified Source(s) of Funding: Department, College, State and/or rium modified atmosphere packaging (EMAP), are well-known to HATCH prolong fresh produce shelf life. However, this technology may need to be combined with other technologies, such a low temperature, to effectively reduce fungal attack. Naturally-occurring plant volatiles, 3:00–3:15 pm such as 2E-hexenal, are well-known for their effectiveness in reducing fungal growth. 2E-hexenal combined with EMAP may be a perfect Student Learning Assessment: Useful or Odious? solution to prolong blueberry shelf life even when berries are exposed Candice Shoemaker* to high temperatures. In addition, the use of biodegradable containers as

Kansas State University, Manhattan KS; [email protected] packaging for blueberry marketing may be a useful solution to reduce ORALS–THURSDAY the environmental impact caused by the petroleum-based clamshell Catherine Lavis container. In this study, blueberries were packed in polylactide (PLA) Kansas State University, Manhattan KS; [email protected] non-vented containers and then 2E-hexenal (10 and 20 microliters) Many of us in higher education are involved, at some level, with as- was injected. Packages without volatile were used as controls. In ad- sessment. New accreditation requirements for assessment in the 1990s dition, commercial petroleum-based vented clamshell containers were required us to respond. This trend for assessment coincided with a used to compare the effectiveness of the new package against today’s second trend for accountability. Unfortunately both trends have been commercial packaging system for fresh blueberries. Physicochemi- erroneously referred to as “assessment” and affected how we responded cal and microbiological changes of blueberries were studied during to our administrations requests. At Kansas State University, when the storage at 23 °C for 12 days. Results showed the effectiveness of this initial request to prepare student learning outcomes and an assessment new packaging system (PLA + 2E-hexanal) in improving blueberry plan was made the overwhelming faculty perception was that it had to shelf life. since both the respiration rate of the fruit and fungal growth do with accountability. This was no different for the horticulture teach- (Alternaria alternata) were reduced. Other quality parameters were ing faculty. And how were horticultural-trained scientists expected to also modified with the presence of the volatile. know anything about SLOs, assessment, direct and indirect measures, Specified Source(s) of Funding: Department, College, State and/or rubrics, and so on. As with other administrative mandates, maybe if HATCH Project GREEEN (Generating Research and Extension to we ignored it or held it off long enough, the issues (like the misguided Meet Economic and Environmental Needs) new administrator) would finally give up and go away. However, as we reluctantly moved through the process of writing SLOs and the assessment plan, implementing the plan, and evaluating the results our perception shifted. The process and components of K-State’s under- 2:15–2:30 pm graduate horticulture program assessment plan will be presented to Differential Degreening and Expression of Ethylene demonstrate this shift in recognizing “assessment for excellence” as Biosynthesis and Signaling Genes in Two Citrus Types an information feedback process to guide students, faculty members, Karthik-Joseph John-Karuppiah* programs, and schools in improving their effectiveness while “assessment for accountability” as essentially a regulatory process, designed University of Florida Lake Alfred FL; jkjoseph@ufl.edu

HORTSCIENCE, VOL. 43(4), JULY 2008 1167 Jacqueline K. Burns* orchards and at both storage temperatures. Overall, our results indicated University of Florida, Lake Alfred; [email protected]fl.edu that flesh browning development in untreated or 1-MCP treated apples during CA storage was related to PPO and POX activities. Two citrus varieties (‘Fallglo’ and ‘Lee × Orlando’) that show differential degreening response when treated with ethylene were selected. Specified Source(s) of Funding: Federal competitive USDA T-Star Fruit were harvested at commercial maturity but at different develop- 83 mental periods. Fruit harvested in early October had an a/b ratio of -0.48 and -0.61 and acid/°Brix ratio of 5.8 and 9.0 for ‘Fallglo’ and ‘Lee × Orlando’, respectively. The rate of color change was greater 2:45–3:00 pm in ‘Fallglo’ than in ‘Lee × Orlando’ when fruit were treated with 5 A Lab Scale Low-pressure Chamber System for ppm of ethylene for 24 hr. The a/b ratios increased to -0.15 and -0.52 and attained maximum value of 0.17 and -0.36 in ‘Fallglo’ and Lee × Conducting Hypobaric Research Orlando, respectively, after 7 days of storage. At the end of the experi- Thomas Davenport* ment, the a/b ratio of control fruit was -0.33 and -0.59 for ‘Fallglo’ University of Florida, IFAS Homestead FL; [email protected]fl.edu and ‘Lee × Orlando’, respectively. Apart from faster degreening rate in ‘Fallglo’, fruit were completely degreened following ethylene Stanley Burg treatment; however, ‘Lee × Orlando’ fruit were not and were green VacuFresh Inc. Miami FL; [email protected] in color. The expression of genes involved in ethylene biosynthesis Peter Follett and signaling pathways were studied in flavedo to test if differences USDA, ARS Hilo HI; [email protected] in these pathways could lead to differential ethylene sensitivity of the citrus types. In ‘Fallglo’, ETR2 receptor expression was induced Commercial scale, low-pressure shipping of fresh produce will soon during and after 24 hr following ethylene exposure; in contrast, be a reality. Invented by the second author, this technology preserves ETR2 expression was not affected in ‘Lee × Orlando’. In ‘Fallglo’, the fresh picked quality of horticulturally mature fruits, vegetables, and expression of ETR1, ACO, ACS1 and Chlase genes were induced flowers far longer than any other method. Its ability to kill quarantine by 3-, 21-, 510- and 40-fold, respectively, after ethylene treatment, insects during shipment has been demonstrated in the Caribbean fruit whereas in ‘Lee × Orlando’, ethylene induced gene expression by 2.3-, fly, and research on this and other insects of quarantine concern is 4-, 233- and 16-fold, respectively. Expression of ERS1, EIN2, EIL1, continuing. Lab scale investigations in the vacuum range necessary and EIL2 was not affected by ethylene in either citrus types. Hence, for efficacious results are plagued by air leaks in equipment that is not degreening results in differential effects on ethylene biosynthesis and designed to operate at such low pressures, thus causing desiccation of signaling pathways in ‘Lee × Orlando’ and ‘Fallglo’, possibly leading the fresh produce. A lab-scale, leak-free vacuum system designed by to a reduced rate of degreening through reduced ethylene sensitivity the authors has been built by Atlas Technologies in Port Townsend, in ‘Lee × Orlando’. The effects of degreening on these citrus types at WA. It provides accurate control and monitoring of the operating two additional developmental periods will be presented. pressure, metered gas flow, and relative humidity in the vacuum chamber regardless of the volume of commodity under investigation. Specified Source(s) of Funding: Private (Association, Foundation, The design features and operation of this system will be discussed in Industry) T.K. McKnight Foundation conjunction with results of current research on postharvest storage of commodities.

2:30–2:45 pm Specified Source(s) of Funding: Department, College, State and/or HATCH Involvement of Ethylene in Browning Development of Apple Fruit Seok-Kyu Jung* 3:00–3:15 pm Cornell University, Ithaca NY; [email protected] Evaluation of Respiration Rate of a Tomato Fruit Using Chris Watkins Near-infrared Spectrophotometry Cornell University, Ithaca NY; [email protected] Yoshio Makino* Flesh browning has been a long term problem for storage of many apple The University of Tokyo Tokyo, Japan; [email protected] cultivars, including ‘Empire’. This cultivar is susceptible to chilling Masayuki Ichimura injury at low storage temperatures and senescent breakdown at warmer The University of Tokyo Tokyo, Japan ;[email protected] storage temperatures, and current storage temperature recommendations are 1-2 °C. In this study we have used 1-methycyclopropene (1-MCP) as Yoshinori Kawagoe a tool to investigate the role of ethylene in browning development. The The University of Tokyo, Tokyo, Japan; [email protected] internal ethylene concentration (IEC), flesh firmness, flesh browning, Seiichi Oshita total phenolic concentrations, and the activities of polyphenol oxidase The University of Tokyo, Tokyo, Japan; [email protected] (PPO) and peroxidase (POX) in flesh tissues have been studied during storage of ‘Empire’ apples. Fruit were harvested from two orchards, An agricultural product deteriorates due to consumption of assimi- either untreated or 1-MCP treated, and they were then stored under lates by respiration. Therefore, evaluation of the respiration rates is CA conditions at either 0.5 or 3 °C. Fruit were removed from stor- effective for determining the shelf life of a product. Conventional age at 1.5-month intervals and evaluated. The 1-MCP-treated apples flow-through or stop-flow methods that use gas chromatography and were firmer than those of untreated apples, and had lower IECs, at sophisticated air-sealing chambers require several hours to measure all removals. After 9 months of CA storage at 0.5 °C, the incidence the respiration rate. The terminal enzyme of the respiratory chain, of browning in untreated apples was 12% and 10% in orchards 1 and cytochrome c oxidase (EC 1.9.3.1), reduces >90% of O2 and absorbs 2, respectively, while 1-MCP treated apples harvested from the two near-infrared light (J bsis, Science, 198, 1264-1267, 1977). In this orchards was 19% and 10%, respectively. In contrast, untreated apples study, we developed a method for rapid evaluation of the respiration stored at 3 °C had browning incidences of 6% and 50% in orchards 1 rate using near-infrared spectrophotometry. Tomato (Lycopersicum and 2, respectively, while 1-MCP-treated apples from both orchards had esculentum Mill., f. Round 1) fruits at various ripening stages (n=155; 85% browning. No major differences in total phenolic concentrations avg. mass 91.5 g) harvested from a farm in Iwaki city, Japan, were were detected between untreated and 1-MCP treated apples at either used in the study. Oxygen uptake and CO2 production rates were storage temperature. However, PPO and POX activities in flesh tissues measured at 15 °C as dependent variables by a closed method using were higher in 1-MCP treated apples than untreated apples from both gas chromatography (Fonseca et al., J. Food Eng., 52, 99-119, 2002).

1168 HORTSCIENCE, VOL. 43(4), JULY 2008 Diffuse reflectance spectra of the fruits were obtained in the range Melinda R. Vinquist-Tymchuk of 700-950 nm as independent variables and were measured using Agriculture & Agri-Food Canada, Kentville, NS Canada; [email protected] a portable FQA-NIR-GUN spectrophotometer (FANTEC Research Institute and International, Kosai, Japan). Calibration equations were Sherry A.E. Fillmore derived using a multiple regression method and validated with JMP Agriculture & Agri-Food Canada, Kentville, NS Canada; fi[email protected] ver. 7.0 software. A visible/near-infrared spectrum for cytochrome c Controlled atmosphere storage of fresh blueberries is effective in oxidase was obtained using UV-3600 spectrophotometer (Shimadzu reducing decay and extending market-life. However, the effects of Co., Kyoto, Japan). A weak absorption band was detected at 865 nm, atmosphere modification on the phenolic composition and nutritional which was due to the absorbance of activated Cu2+ present in the en- value of the fruit are not well understood. Therefore, 3 cultivars of zyme. The absorbance at wave lengths near 865 nm was selected as an highbush blueberries (‘Duke’, ‘Bluecrop’, and ‘Brigitta’) were stored independent variable of calibration lines for calculating the respiration at 0 °C under 9 combinations of O2 and CO2 ranging from 1 to 15 and rates (multiple correlative coefficient 0.77; standard error prediction 0 to 16 kPa, respectively. Fruit were analyzed for antioxidant capacity 0.11 mmol·kg-1·h-1). Thus the absorbance at the wave lengths may (ORAC), total phenolics, anthocyanins, and tannins following 3, 6, be effective for evaluating respiration rate. and 9 weeks of storage. Atmosphere composition did not affect these Specified Source(s) of Funding: Grant-in-Aid for Scientific Research parameters, but they differed among cultivars and changed during (No.19380140) from Japanese Society for the promotion of Science storage. ‘Duke’ had the highest antioxidant capacity (32.8 µmol trolox equivalents (TE)/g FW) and concentration of total phenolics (2.01 mg gallic acid equivalents (GAE)/g FW) and anthocyanins (1.36 mg cyanidin 3-glucoside equivalents (CGE)/gFW), while ‘Brigitta’ had 3:15–3:30 pm the lowest antioxidant capacity (24.0 µmol TE/g FW) and ‘Bluecrop’ Effects of Controlled Atmosphere Storage on had the lowest concentration of total phenolics (1.43 mg GAE/g FW) Antioxidant Capacity and Phenolics in and anthocyanins (0.61 mg CGE/gFW). ORAC and the concentration Three Highbush Blueberry Cultivars of phenolics and anthocyanins decreased during storage at a rate of 0.43 µmol TE/g FW/week, 0.025 mg GAE/g FW/week, and 0.022 mg Charles F. Forney* CGE/gFW/week, respectively. The correlation coefficient of ORAC Agriculture & Agri-Food Canada, Kentville, NS Canada; [email protected] with total phenolics and anthocyanins was 0.747 and 0.551, respec- Wilhelmina Kalt tively. The concentration of tannins, which are polymerized pheno- Agriculture & Agri-Food Canada, Kentville, NS Canada; [email protected] lics, followed an opposite trend. Tannins were greatest in ‘Bluecrop’ (22.4%), least in ‘Duke’ (12.5%), and increased during storage at Michael A. Jordan an average rate of 0.48%/week. The correlation coefficient between Agriculture & Agri-Food Canada Kentville NS Canada jordanm@agr. ORAC and tannins was -0.288. Changes in phenolic antioxidants gc.ca during commercial storage should be considered in order to optimize the nutritional and sensory properties of fruit, like blueberries, that are rich in these compounds. ORALS–THURSDAY

HORTSCIENCE, VOL. 43(4), JULY 2008 1169 Undergraduate Student Oral Competition Monday, 21 July 1:15–2:00 pm Salon 11

1:15–1:30 pm a year had international tours. Recently, international activity has In Vitro Shoot Proliferation of ‘Dog Ridge’ Grapevine increased, such that in 2007, 50 people, including undergraduate Kah-Yat Isaac Wong* and graduate students and faculty, were able to have an interna- Texas A&M University; [email protected] tional experience. There are two structured opportunities: a 10-day non-credit study tour, sponsored by the Henry P. Orr Endowment, R. Daniel Lineberger and a for-credit study abroad program. The purpose of the study Texas A&M University; [email protected] tour is to recognize outstanding students and enable them, along with one to two professors, to explore horticultural operations Vitis champini ‘Dog Ridge’ is a highly desirable grape rootstock (gardens, production areas, etc.) and other cultures. Students are for Texas because of its disease resistance. Some have reported selected by a committee based on their academic performance, this selection to be difficult to root through hardwood cuttage, as faculty references, impact statement, extracurricular involvement, is often practiced for grapevine. This study was undertaken to and interview performance. The study tour began in 2003, and oc- establish a protocol to proliferate shoots of ‘Dog Ridge’ grapevine curs annually between the spring and summer semesters; the study in vitro by comparing combinations of explant type, basal salts, abroad program is designed to provide undergraduate students with and benzyladenine (BA) concentration. Shoot tip and axillary an equivalent of a semester’s worth of credit in another country bud explants were harvested from actively growing stock plants, with exposure to a broader perspective of horticulture. Students disinfected with 10% Clorox (v/v), rinsed in sterile distilled water, earn up to 16 credits, including courses in landscape gardening, and cultured on either Murashige and Skoog (MS) or Woody Plant garden history and design, international agriculture, herbaceous Medium (WPM) containing 0, 4.4, or 8.8 µM benzyladenine for 12 plant materials, and plant growth and development. The teaching weeks. Axillary bud explants cultured on MS medium proliferated is subcontracted to Myerscough College in northwest England, better than shoot tip or bud explants regardless of the basal salts with at least one Auburn faculty member on site at all times for used. Lateral bud explants cultured on media containing 4.4 or 8.8 supervision, tutorial, and organization of trips. Occurring every µM BA proliferated better than shoot tip explants regardless of other year, the study abroad program takes place in summer the BA concentration in the medium. Increasing the concentration semesters. The variety of these two programs, among others, ac- of BA in the medium resulted in poor leaf expansion. Shoot tip commodates the diverse student population offering opportunities explants cultured in WPM containing no BA rooted frequently, to enrich the curriculum. suggesting that changing basal salts during in vitro rooting phase might be beneficial. Additional studies must be conducted to determine optimal media for multiplication of established cultures 1:45–2:00 pm and to identify methods for rooting and establishment of plants in the greenhouse. Control of Microbial Growth and Browning on Pre-cut Apples Thomas Bottoms* 1:30–1:45 pm California Polytechnic, San Luis Obispo; [email protected] Undergraduate International Opportunities: Two J. Wyatt Brown* Approaches California Polytechnic, San Luis Obispo; [email protected] Laureanne Bond* Auburn University; [email protected] Enzymatic browning is the major factor affecting the aesthetic quality of pre-cut fruits and vegetables. Multiple formulations Carolyn W. Robinson were tested to determine the efficacy of antibrowning agents in Auburn University controlling the microbial growth on and browning of pre-cut Amy N. Wright apples stored at 4.4 °C, 90% RH. All formulations were tested against NatureSeal® (Mantrose-Haeuser Co., Westport, Conn.), a Auburn University; [email protected] formula primarily consisting of calcium ascorbate. Total aerobic Jeff L. Sibley plate count (APC), coliforms, yeasts, and molds were determined Auburn University; [email protected] at 0, 7, 14 or 21 days for mixtures that were effective in controlling browning. A mixture containing 3% ascorbic acid, 2% citric Donald J. Eakes acid, 0.2% CaCl2, and 2% sodium polyphosphate was developed Auburn University that controlled browning and microbial growth on apple slices for The Auburn University Department of Horticulture is nationally at least 14 days. As a minimum of 17 days without browning is recognized as having one of the largest undergraduate student required by the pre-cut apple industry, further research is needed enrollments in the nation with a strong emphasis on internships. to refine the formula to yield a mixture which will control both Over the past 6 years, the department has increased international microbes and browning for at least 17 days. opportunities within its program. Prior to 2000, about 10 people

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