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Effects of Floral Position, Stamen Quality, Hand Pollination, And

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Effects of Floral Position, Stamen Quality, Hand Pollination, And AN ABSTRACT OF THE THESIS OF Elena L. Alba for the degree of Master of Science in CROP SCIENCE presented on September 10, 1986 Title: EFFECTS OF FLORAL POSITION, STAMEN QUALITY,HAND POL- LINATION, AND TEMPERATURE DURING REPRODUCTIVEDEVEL- OPMENT ON MEADOWFOAM SEED SET ANDSEED YIELD Redacted for orivacy Abstract Approved: V l'f/4 Dr. Gary D. Jolliff Inconsistent seed yields of meadowfoam (Limnanthesalba Benth.) interfere with profitable production of thisnew oilseed crop. Significant correlation of fieldgrown meadowfoam seed yields with years having temperatures above 240Cin mid-May at Corvallis, OR., led to the hypothesis that ambienttemperature during reproductive development affects meadowfoam seed yields. The objective of this experimentwas to determine the effect of three day/night temperature regimes (16/10, 24/10, 32/100C), imposed for seven days during bud, earlyflowering or peak bloom stages on seed yield, seed numberper flower, and seed weight of meadowfoam when grown undera controlled environment. In separate experiments, studies were performed to verifythe effectiveness of a hand pollination technique in field-grown meadowfoam;and influences of flower location and stamen qualityon seed set in hand-pollinated growth chamber-grown meadowfoamwere examined. No significant differences in seed setwere found among flowers at different locations on the plants,nor in flowers having normal or abnormal anthers. Supplementally hand-pollinated flowers of field-grown meadowfoam setmore seed than bee-pollinated flowers on the same plants. Temperature and floral stage treatments did not result in significant seed numberor seed size (1000-seed weight) differences, but high temperature (320C) imposedat the bud stage did increase seed yield (total weight of allseeds produced per plant). High temperature did not increase seed yield whenimposed at early flowering or peak bloom. Temperature during reproductive development does appear to playan important role in determining meadowfoam seed yield, and further researchis necessary to determine the extent of seed yieldresponse to temperature in the field. EFFECTS OF FLORAL POSITION, STAMENQUALITY, HAND POLLINATION, AND TEMPERATUREDURING REPRODUCTIVE DEVELOPMENT ON MEADOWFOAM SEED SET AND SEED YIELD by Elena L. Alba A THESIS submitted to Oregon State University in partial fulfillment of the requirements for the degree of Master of Science Completed September 10, 1986 Commencement June, 1987 APPROVED: Redacted for privacy Professor ofrop Scie ce in Charge of Major Redacted for privacy Head of Department of Crop Science Redacted for privacy Dean o uateSchoc111 Date Thesis is Presented: September 10, 1986 TABLE OF CONTENTS Page INTRODUCTION 1 CHAPTER I. REVIEW OF LITERATURE 4 CHAPTER II. EFFECTS OF FLORALPOSITION, STEMEN QUALITY, HAND POLLINATION, AND TEMPERATURE DURINGREPRODUCTIVE DEVELOPMENT ON MEADOWFOAM SEED SETAND SEED YIELD. 11 Introduction 11 Materials and Methods 14 Results 21 Discussion 32 CHAPTER III. SUMMARY AND CONCLUSION 36 BIBLIOGRAPHY 39 APPENDIX 43 LIST OF APPENDIX TABLES Table Page Table 1. Number of meadowfoam seedsproduced per hand- 44 pollinated flower as affectedby flower position. Table 2. Analysis of variance for numberof meadowfoam 45 seeds produced per floweras affected by flower position. Table 3. Number of meadowfoam seeds producedper hand- 46 pollinated flower on 15 normal flowersand 15 flowers with abnormalstamens. Table 4. Analysis of variance for number ofmeadowfoam seeds 47 produced per floweron 15 normal flowers and 15 flowers with abnormalstamens. Table 5. Mean number of meadowfoam seeds producedper 48 flower on 10 field-grown plants with 30flowers bee-pollinated and 30 flowers supplementally hand-pollinated. Table Page Table 6. Mean number of meadowfoam seedsproduced per flower 49 on 30 flowers of each of 10 plants in 2replications of 3 temperatures and 3 floralstages. Table 7 Mean number of meadowfoam seedsproduced per flower 50 under 3 temperatures and 3 floralstages. Table 8. Meadowfoam seed weight (milligrams)produced per plant 51 by 30 flowers on each of 10 plantsin 2 replications of 3 temperatures and 3 floralstages. Table 9. Mean weight (milligrams)per meadowfoam seed produced 52 per plant under 3 temperatures and 3 floralstages. Table 10. Meadowfoam seed yield(total seed weight produced per 53 plant, in grams) produced by 30flowers on each of 10 plants in 2 replications of 3temperatures and 3 floral stages. Table 11. Mean meadowfoam seed yield(total seed weight produced 54 per plant, in grams) under 3 temperatures and 3 floral stages. Table 12. Analysis of variance of the effects of3 temperatures 55 imposed during 3 flowering stages on seed yield of meadowfoam. Table Page Table 13. Coefficients of determinationderived from linear 56 regressions of climatic data against yieldof meadowfoam seed from 1975 to 1983. Table 14. Schedule of meadowfoamseeding, transplanting and 57 growth chamber use for 3temperature and 3 floral stage treatments. LIST OF FIGURES Figure Page Fig. 1 Meadowfoam seed yields at Hyslop Crop ScienceField 2 Laboratory, Corvallis, Oregon, from 1975 to 1985. Fig. 2 Patterns of light/dark cycle and temperaturetreat- 19 meet regimes for study of temperature effectson meadowfoam seed yield. Fig. 3 Effects of three temperature treatments at three 25 stages of reproductive developmenton number of seeds per flower in meadowfoam plants. Fig. 4 Effects of three temperature treatments at three 27 stages of floral development on meadowfoam seed size. Fig. 5 Effects of three temperature treatments at three 29 stages of floral development on yield (total seed weight per plant) in meadowfoam. LIST OF TABLES Table Page Table 1. Treatment means and stistical comparisons for number of seeds producedper meadowfoam flower in 22 three experiments using hand pollination. Table 2. Treatment means and statistical comparisons for 24 seeds per flower, seed size and total seedweight (yield) of meadowfoam under threetemperatures and three stages of floral development. EFFECTS OF FLORAL POSITION, STAMENQUALITY, HAND POLLINATION AND TEMPERATURE DURING REPRODUCTIVEDEVELOPMENT ON MEADOWFOAM SEED SET AND SEED YIELD INTRODUCTION Meadowfoam is a winter annualnative to the Pacific Coast areas of southern Oregon, California, and VancouverIsland, British Columbia. Meadowfoam seed contains 25 to 33% oilprimarily composed of C20 and C22 fatty acids,with unsaturation at the fifth and/or the thirteenth carbonatoms. This unusual structure allows meadowfoam seed oil to remain clearand fluid at temperatures as high as 1800C, making it potentiallyuseful as an industrial lubricant additive. Other uses have been suggested, and the first commercial sale of the oilwas to a Japanese firm in 1985 for use in cosmetics. Meadowfoam is a crop of special interestin the Willamette Valley of Oregon because it isadapted to the mild, wet winters and the poor internal drainage typicalof approximately 80,000 hectares of soils in the region. In recent decades annualryegrass for seed has been the only adapted cashcrop which growers could produce on these soils. Air pollution caused by the burning ofryegrass seed crop residue, and severe fluctuations in the price of annual ryegrass seed have resulted in a serious need for alternative crops. High seed yields could make meadowfoama profitable alternative for farmers, but seed yields from experimental 1.7 1.5 1.3 1.1 0.9 0.7 75 76 77 78 79 80 81 82 83 84 85 Years Figure 1. Meadowfoam seed yields at Hyslop Corp Science Field Laboratory, Corvallis, Oregon, from 1975 to 1985. 3 production trials at Oregon StateUniversity have been inconsistent, varying from 788 to 1760kg/ha (Fig. 1). The factors contributing to yearly fluctuationsin seed yield in the Willamette Valley of Oregon have not beenidentified. A significant positive correlation was found between seed yieldand the number of days having average maximum temperatureabove 24°C from May 10th to May 17th (Appendix Table 13). The objective of this researchwas to test the hypothesis that temperaturevariation during reproductive development can affect seed yield. Additional experiments were performed to validate samplingtechniques, examine differences in flower quality, and verify theeffectiveness of a hand pollination procedure. 4 CHAPTER I REVIEW OF LITERATURE Temperatures during reproductive developmentare known to affect plant processes contributingto final seed yield by influencing seed number, seed size,or both. The number of seeds produced by a plant is dependentupon: the number of reproductive structures that differentiate and successfullydevelop, successful pollination and fertilization, andfinally sufficient dry matter accumulation to mature the seed. Environmentalstress present during any one of these phases couldprevent a plant from reaching its full genetic potential for seedyield. Gamete differentiation and development, pollination, andfertilization are especially sensitive to temperature extremes (Leopoldand Kriedemann, 1975; Stanley and Liskens, 1974). Elevatedtemperatures during premeiotic or meiotic stages can disturb cell division and result inreduced gamete viability (Carlson and Williams,1985). Low temperatures induce male sterility insome cereals and in strawberry (Kinet et al., 1985), whereas favorabletemperatures promote pollen germination and pollen tube growth (Savithri et al.,1980). Whole flower abortion often results from theexposure of emerging flower buds to either high or low temperatureextremes (Brevedan et al., 1978). The rates at which many reproductiveprocesses occur
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