Quick viewing(Text Mode)

Trends in U.S. Sweet Orange, Grapefruit, and Mandarin-Type Cultivars

Trends in U.S. Sweet Orange, Grapefruit, and Mandarin-Type Cultivars

the result of hybridization between Trends in U.S. Sweet , , these progenitor , subsequent and Mandarin-type hybridization and rehybridization between progenitor species and pre- viously derived hybrids, fi xation of Ed Stover1, William Castle2, and Chih-Cheng T. Chao3 identifi able types through , and derivation of sports (either - sports or sports derived from apomictic ADDITIONAL INDEX WORDS. , grapefruit, , mandarin, orange, processing embryos) to yield diversity within apomictic “species” (Fig. 1). For easy SUMMARY. The world market for citrus (Citrus spp.) products has undergone dramatic shifts over the last decade. These shifts are infl uencing development and reference, the cultivars mentioned in planting of new citrus cultivars. Seedlessness and very easy peeling have become this paper are listed in Table 1. paramount in mandarin types (C. reticulata and hybrids), and new cultivars are being developed through breeding and selection of new sports. In both Market demands sweet orange (C. sinensis) and grapefruit (C. paradisi), essentially all important For commercial producers, seri- cultivars are derived from a single original of each type, and plant ous discussion of cultivars should occur improvement has focused on selection of sports with redder color and extended within the context of market demands maturity. The existence of many active citrus breeding programs makes it likely and trends. The world market for cit- that we will continue to see evolution of new citrus cultivars over the foreseeable rus products has undergone dramatic future. shifts over the last decade. Increased global trade in has provided Introduction to the origin of grandis)], and C. medica (the ), many consumers with opportunities citrus cultivars with various obscure species making to buy almost any fruit year-round. more minor contributions (Nicolosi Thus, fresh citrus no longer dominates he genus Citrus is comprised of et al., 2000). Most commercial citrus fruit sales. Also, several other numerous genotypes produc- types are believed to have originated in trends affect the attractiveness of fresh Ting a wildly divergent array of the region from through citrus fruit. fruits. Only the genus Prunus, source northeastern (Hodgson, 1967). Consumers appear to be less will- of almond (P. dulcis), apricot (P. arme- The evolution of citrus appears to be ing to spend time preparing fruit for niaca), sweet cherry (P. avium), sour cherry (P. cerasus), /nectarines (P. persica), and plums (P. domestica, P. cerasifera, P. salicina, and hybrids) can begin to compete for the sheer variety of fruit crops found within a single ge- nus. Citrus displays a strong tendency for apomixis. Many genotypes form numerous embryos per , with most genetically identical to the mother tree. This has had a profound infl uence on the development of cultivars and even apparent species (Hodgson, 1967). Numerical taxonomic evaluation sug- gested that three “true” species are primary contributors to the amazing array of distinctive commercial citrus types that we now know (Barrett and Rhodes, 1976; Scora, 1975), and this notion has been supported by recent molecular studies (Moore, 2001; Nico- losi et al., 2000). These species are C. reticulata (the mandarins), C. maxima [the pummelos (formerly known as C.

1Indian River Research & Education Center, Univer- sity of , Ft. Pierce, FL 34945; current address USDA/ARS, National Clonal Germplasm Repository, One Shields Avenue, Davis, CA 95616. Fig. 1. Deduced origins of many major citrus types of commerce: three 2University of Florida, Citrus Research and Education Center, 700 Experiment Station Rd., Lake Alfred, “true” species of citrus hybridized with some contribution of other sources to FL 33850. produce “hybrid” species that have been sustained through apomixis and veg- 3Department of Botany and Plant Sciences, University etative propagation. Relationships expressed in the fi gure are based on molecu- of –Riverside, Riverside, CA 92521. lar marker data presented by Nicolosi et al. (2000). Diverse cultivars of sweet Florida Agricultural Experiment Station Journal Series orange and grapefruit have developed from presumed original hybrids through No. R-10819. sports.

● July–September 2005 15(3) 501

JJuly05HT.indbuly05HT.indb 550101 66/8/05/8/05 22:24:01:24:01 PPMM WORKSHOP

Table 1. Citrus cultivars discussed in this review of trends in U.S. sweet orange, grapefruit, and mandarin-type cultivars. Cultivar or type Type Notes Common-types Sweet orange Sweet orange category that includes most cultivars Navel-types Sweet orange variants with distinctive secondary-fruit forming “navel” Blood-types Sweet orange variants with considerable production in cool climate Acidless-types Sweet orange variants with very low acidity Ambersweet Hybrid Florida hybrid that resembles sweet orange, derived from (‘’ x ‘Orlando’) x unnamed sweet orange Delta Sweet orange South African selection of ‘Valencia’ reported to have better quality Earlygold An early-season common orange, with better early color than ‘Hamlin’ Hamlin Florida’s most widely planted early-season common orange Itaborai An early-season common orange, with better early color than ‘Hamlin’ Midknight South African selection of ‘Valencia’ reported to have better dessert quality A mid-season common orange most associated with Florida production Rohde Red Florida selection of ‘Valencia’ with more red in fl esh and An early-season common orange, with better early color than ‘Hamlin’ Smith Red Valencia New California selection of Valencia Word-wide late-season common orange that is the standard-bearer for juice quality Westin Brazilian early-season common orange, with better early color than ‘Hamlin’ Arrufatina Mandarin-type Spanish selection of ‘Clementine’ that is seedless in isolation Bekria Moroccan selection of ‘Clementine’ that is seedless in isolation Clemenpons Spanish selection of ‘Clementine’ that is seedless in isolation Clementine Easy-peeling mandarin type with many selections that are seedless in isolation, named as a selection in Algeria, may be the Chinese cultivar Canton Old Florida mandarin-type, seedy and easy-peeling Fallglo Early-maturing, seedy mandarin-type derived from ‘Bower’ x ‘Temple’ Fina Sodea Moroccan selection of ‘Clementine’ that is seedless in isolation Nugget New California seedless mandarin-type derived from ‘Wilking’ x ‘Kincy’ Hernandina Spanish selection of ‘Clementine’ that is seedless in isolation Loretina Spanish selection of ‘Clementine’ that is seedless in isolation Marisol Spanish selection of ‘Clementine’ that is seedless in isolation Popular late Florida mandarin-type, likely mandarin x sweet orange, also known as ‘Honey ’ Nour Moroccan selection of ‘Clementine’ that is seedless in isolation Nules Spanish selection of ‘Clementine’ that is seedless in isolation, also known as ‘Clemenules’ Oroval Spanish selection of ‘Clementine’ that is seedless in isolation Osceola Florida mandarin, derived from ‘Clementine’ x ‘Orlando’ Robinson Florida mandarin, derived from ‘Clementine’ x ‘Orlando’ Satsuma Seedless, easy-peeling mandarin-type, there are many selections of ‘Satsuma’ and they are widely grown in and Shasta Gold New California triploid derived from (‘Temple’ x 4n ‘Dancy’) x ‘Encore’ Sunburst Florida mandarin type derived from ‘Robinson’ x ‘Osceola,’ easy peeling but seedy Tahoe Gold New California triploid derived from (‘Temple’ x 4n ‘Dancy’) x ‘Encore’ Temple Older mandarin-type, likely mandarin x sweet orange W. Murcott Moroccan of ‘Murcott’ that is seedless in isolation, also known as ‘Afourer’ Yosemite Gold New California triploid derived from (‘Temple’ x 4n ‘Dancy’) x ‘Encore’ LB8-9 -type New Florida ‘Minneola’ like cultivar derived from ‘Clementine’ x ‘Minneola,’ will soon be released Minneola Tangelo Florida selection derived from ‘’ grapefruit x ‘Dancy’ mandarin, has a distinctive neck, also known as ‘Honeybell’ Orlando Florida selection derived from ‘Duncan’ grapefruit x ‘Dancy’ mandarin Duncan Grapefruit Florida selection of seedy white grapefruit considered similar to original grapefruit derived from pummelo x sweet orange Flame selection of seedless red grapefruit derived as apomictic seedling from ‘Henderson’ Marsh Florida selection of seedless white grapefruit derived as budsport from ‘Duncan’ Ray Ruby Texas selection of seedless red grapefruit derived as budsport from ‘Redblush’ Redblush Texas selection of seedless red grapefruit derived as budsport from ‘Thompson’ Rio Red Texas selection of seedless red grapefruit derived through irradiation of ‘Ray Ruby’ Ruby Texas selection of seedless red grapefruit derived as budsport from ‘Thompson’ Star Ruby Texas selection of seedless red grapefruit derived through irradiation of ‘Hudson’ Thompson Florida selection of seedless pink grapefruit derived as budsport from ‘Marsh’

502 ● July–September 2005 15(3)

JJuly05HT.indbuly05HT.indb 550202 66/8/05/8/05 22:24:02:24:02 PPMM consumption (i.e., peeling, slicing, Monte, 2001) and other minimally end of the primary fruit. removing , etc.), but are willing processed products, such as frozen juice Blood oranges have distinctive to spend more for ready-to-eat (i.e., vesicles, are being explored to increase red fl esh and often peel coloration “fresh-cut”) products (Ragaert et al., utilization and consumer demand for from anthocyanin pigments, and are 2004). U.S. consumers often want fruit fresh citrus. Not-from-concentrate primarily grown in western Mediter- they can eat while driving in their cars! and reconstituted juice now dominate ranean countries (Saunt, 1990). Red U.S. residents consume 19% of their the U.S. market (Brown and Brown, pigmentation is enhanced by cool meals in cars, according to research by J. 2001). The not-from-concentrate temperatures, and distinctive blood- Nihoff (Lednicer, 2003), a professor at market has increased demand for high orange color is undeveloped in Florida the Culinary Institute of America. One soluble solids and high-color early or- and other warm climate citrus regions, in fi ve Canadians also eats breakfast “on anges, and efforts continue to expand but their fl avor, often described as the go” (Ipsos-Reid, 2003). the harvest period for top-quality juice -like, can be present. The Florida fresh citrus producers ‘Valencia’. acidless oranges are very low in acid are feeling these changes. Returns Pome and stone fruit produc- with a very sweet, but insipid fl avor are dwindling for delicious but seedy ers have entered an era in which the to many palates. Although grown for and hard-to-peel mandarin types, and most popular new cultivars provide local consumption in Mediterranean are often very low for navel oranges tremendous returns to growers while regions, , , and and grapefruit (Florida citrus grow- established commodity cultivars often , they are of minor importance ers, personal communications). The provide returns near production costs. in most citrus-producing regions (Wil- high juice content that characterizes In personal conversations, ( liamson and Jackson, 1993). Florida citrus may be a detriment for ×domestica) growers in western Europe ‘Valencia’ is the leading cultivar eating fruit out of hand. Grapefruit and New Zealand have indicated that of sweet orange in both Florida and sales are suffering the additional blow orchard commercial life may only be the world. The juice color and qual- of warnings against consumption with 10–12 years because of a constant ity are the standards of excellence by many medications (Associated Press, demand for newer cultivars. The New which other sweet orange cultivars are 2001). The risk of interactions Zealand apple industry plans to capi- judged. Fruit store exceptionally well with grapefruit may be exaggerated talize on this trend by introducing a on the tree but may re-green during late (Associated Press, 2001), but debate new cultivar every 2 years (DeMarree, spring or early summer. Just as existing continues. 2003) and substantial acreage is planted cultivars appear to be mutants of the The world fresh citrus industry to yet unnamed cultivars. With several original sweet orange (Fang and Roose, is experiencing substantial movement active citrus breeding programs around 1997), new cultivars continue to arise toward very-easy-peeling seedless the world, we may soon see the same through identifi cation of desirable mandarins, most notably ‘Clementine’ strategy in . . For example, ‘Rohde Red’ (Brown and Brown, 2001). Sweet Valencia is a Florida selection with bet- oranges continue to be the largest Sweet orange cultivars ter juice color (Rouse, 2000). ‘Delta’ category of dessert citrus sold world- Sweet orange remains the most and ‘Midknight’ are recent late-season wide (~55%) and grapefruit still make widely grown citrus fruit in the world. selections of South African origin with up about 10% of world fresh citrus Florida produces about 80% of U.S. better dessert fruit quality (Tribulato sales, but mandarins and hybrids now sweet oranges with 95% used for pro- et al., 2001). Efforts are under way account for 30% of sales (Florida De- cessing (Florida Department of Citrus, to accelerate generation of mutations partment of Citrus, 2003) and likely 2003) while most of the remaining U.S. in sweet orange and to select strains a much higher percentage of world production is used fresh. Sweet orange with improved fruit quality or altered profi ts on fresh citrus. In California, cultivars can be categorized into four maturation in somaclonal variants ‘Valencia’ plantings are being removed distinct groups: common oranges (also derived from tissue culture (Grosser at a rapid rate and orchards of seed- known as blond oranges in Europe et al., 2000). less mandarins are often springing up and round oranges in Florida), navel Several other sweet orange cul- in their place The bearing acreage of oranges, blood oranges, and acidless tivars, with early juice color superior Valencia decreased from 65,000 to oranges (Hodgson, 1967). These to the standard ‘Hamlin’, interesting 60,000 acres (26,305 to 24,281 ha) distinctive types appear to have arisen fl avor, and/or good soluble solids, in 2002 in California, while California through successive mutations derived have become routinely planted in mandarin production increased by from a single original sweet orange Florida over the last few years (Castle 27% from 2002 to 2003 (National (Fang and Roose, 1997), which was and Ferguson, 2003). Interest in these Agricultural Statistics Service, 2004). likely a pummelo x mandarin hybrid cultivars, such as ‘Earlygold’, ‘Itabo- Paralleling this trend toward very-easy (Nicolosi et al., 2000). In Florida, most rai’, ‘Ruby’, and ‘Westin’, has been peelers, the market for small volumes oranges of economic importance are triggered by the rise in importance of of very-high-quality specialty fruits common oranges, such as the familiar not-from-concentrate juice, since early remains strong, but there are some ‘Hamlin’, ‘Pineapple’, and ‘Valencia’. maturing, high quality juice oranges risks: 1) failure to attract consumer While ‘Valencia’ is the most important reduce the duration and volume of ‘Va- interest; and 2) overproduction, which single cultivar worldwide, navel types lencia’ juice that must be stored during drives down prices. are widely considered the preeminent the summer and fall. Bureau of Citrus The processed citrus market is dessert orange (Saunt, 1990). Navel Budwood Registration (2002) records also responding to shifting consumer oranges are characterized by a small, indicate that about 1.6 million trees demand. Fresh-cut citrus products (Del secondary fruit embedded in the stylar of these selections were propagated

● July–September 2005 15(3) 503

JJuly05HT.indbuly05HT.indb 550303 66/8/05/8/05 22:24:02:24:02 PPMM WORKSHOP

from 1999 through 2002. The most to be limb sports of ‘Thompson’), and over 100 satsuma cultivars that differ popular selection has been ‘Earlygold’ ‘Ray Ruby’ (found in a ‘Redblush’ in date of maturity, fruit shape, color, (59% of the total), followed by ‘Westin’, grove) (Williamson, 1997). Simi- and quality (Ferguson, 1996). Outside ‘Itaborai’, and ‘Ruby’. larly, the deep-red ‘Flame’ cultivar is of Japan, ‘Satsuma’ mandarins are a Because sweet orange is grown so a spontaneous following a minor but sometimes important part extensively around the world, many different succession of cultivars from of the cultivar mix. In warmer regions sports will continue to be found. The ‘Marsh’ (Saunt, 1990). Texas A&M like much of Florida, they lose acidity most recent named sport is ‘Smith University has developed several deep quickly and have a brief window of Red Valencia’, a blood orange identi- red grapefruit cultivars through use market suitability. They are very prone fi ed in California after a homeowner of irradiation to accelerate mutation. to puffi ng, and postharvest quality has repeatedly called the extension agent ‘Star Ruby’ and ‘Rio Red’ were both been less consistent than the ‘Clem- to complain that a neighbor was inject- identifi ed following gamma irradiation entine’ described below. However, ing her fruit with blood (L. Ferguson, of budwood (Saunt, 1990). Even red- ‘Satsuma’ is unique as a very-easy personal communication). der sports, some with distinctive fl avor peeler that does not require isolation Only one sweet orange type has characteristics, continue to be found in from other to remain seedless. clearly arisen from controlled hybrid- the block where ‘Rio Red’ was found. For this reason, there are California ization: ‘Ambersweet’, released by the Remarkable new cultivars will most trials with ‘Satsuma’ selections in an USDA in 1989 by C.J. Hearn. It is a likely be released from this program effort to identify superior genotypes. hybrid of ‘Clementine’ mandarin by (E. Louzada, personal communica- Interestingly, some of these selections ‘Orlando’ tangelo (grapefruit x man- tion). New grapefruit cultivars may have distinctive fl avors or have early darin hybrid) crossed with a seedling also emerge from somaclonal variants maturity that may provide additional mid-season sweet orange. ‘Amber- derived from tissue culture (Grosser marketing opportunities. sweet’ is an early-season cultivar with et al., 2000). There are two stories about the good juice color and a distinctive fl avor origin of ‘Clementine’, the fi rst that when mature. It is somewhat earlier Mandarin-type cultivars it is a hybrid discovered by Father than navel and was widely planted in Unlike sweet oranges and - Clement in Algeria, and the second Florida after its release. However, poor fruit, many cultivars of mandarin-type that it is a traditional cultivar grown production (Albrigo et al., 2001) and fruit have been developed through in China (Saunt, 1990). This original low juice content have largely elimi- hybridization. ‘Sunburst’, a ‘Robinson’ ‘Clementine’ is a good but seedy nated this cultivar from commercial x ‘Osceola’ hybrid, is the most widely mandarin. The major breakthrough production in Florida. grown commercial early mandarin of commercial signifi cance was the type in Florida. ‘Sunburst’ fruit are a discovery of ‘Clementine’ that was Grapefruit cultivars beautiful deep orange color and have seedless when grown away from other Grapefruit cultivars have also a delicious fl avor, require pollenization effective pollen sources. Gibberellic arisen through mutations from a for good fruit set and generally aver- acid should be applied after peak bloom single original grapefruit genotype. age between 10 to 20 seeds per fruit to enhance set of parthenocarpic fruit Grapefruit were fi rst reported grow- (Futch and Jackson, 2003a). ‘Murcott’ for most ‘Clementine’. Seedless ‘Cle- ing in about 1750, where (also called ‘Honey Tangerine’), likely mentine’ has become the darling of they were known as “”. a cross between a mandarin and a sweet citrus regions that can produce it and Since that time, the development of orange, is grown globally and is the the scourge of regions that cannot. At all commercially signifi cant cultivars most widely grown late mandarin type its best, seedless ‘Clementine’ offers through bud sports is well documented in Florida. As with ‘Sunburst’, the color the consumer a very-easy-peeling fruit, (Gmitter, 1995). Molecular marker and fl avor are exceptional but fruit with no seeds, and no release of juice evaluations are consistent with the tend to be quite seedy, but ‘Murcott’ when the sections are separated: the reported origin of grapefruit cultivars is self-compatible (Futch and Jackson, perfect citrus to eat while driving. It through mutation (Fang and Roose, 2003b). The citrus hybrid ‘Fallglo’ also has very satisfactory postharvest 1997), and the fi rst grapefruit was is the result of a 1962 cross between performance. Spain has been at the probably a pummelo x sweet orange ‘Bower’ and ‘Temple’. ‘Fallglo’ is forefront of developing seedless ‘Cle- hybrid (Nicolosi et al., 2000). marketed before ‘Sunburst’ is ready in mentine’ through selection of sports The original grapefruit was very Florida, is very seedy, and has a history and refi ning of production techniques. seedy and yellowish-white fl eshed, and of postharvest problems related to de- Seedless cultivars include ‘Arrufatina’, likely very similar to the cultivar Dun- greening (Futch and Jackson, 2003c). ‘Clemenpons’, ‘Fina Sodea’, ‘Hernan- can. Seedy cultivars quickly went out of Profi tability of these seedy cultivars has dina’, ‘Loretina’, ‘Marisol’, ‘Nules’ demand following the discovery of the been wildly variable and appears to be (sometimes called ‘Clemenules’), seedless ‘Marsh’ (also known as ‘Marsh threatened by production of seedless and ‘Oroval’ (Saunt, 1990), and new Seedless’, still the most widely planted mandarin types. cultivars seem to be introduced on a grapefruit in the world (Williamson, ‘Satsuma’ mandarins are easy peel- routine basis . ‘Bekria’ and ‘Nour’ are 1997), and subsequent cultivar releases ing and seedless even when planted two seedless ‘’ identifi ed have focused on increasingly red fl esh with diverse cultivars that may provide in . Production of seedless and peel. Color intensity increases in viable pollen. The citrus industries of ‘Clementine’ appears to be much more the progression of ‘Thompson’ (or both China and Japan heavily em- diffi cult in the more stressful spring ‘Pink Marsh’, a limb sport of ‘Marsh’), phasize ’Satsuma’. Selection of slight of Florida’s subtropical climate than ‘Redblush’ and ‘Ruby’ (both believed mutations and has resulted in in Mediterranean climates. ‘Clemen-

504 ● July–September 2005 15(3)

JJuly05HT.indbuly05HT.indb 550404 66/8/05/8/05 22:24:03:24:03 PPMM tine’ is now being actively planted in bell-shaped. This appearance has given tionships in cultivated Citrus and its close California. rise to the name “Honeybell” in the gift relatives. Systematic Bot. 1:105–136. A new cultivar has arisen which fruit trade (Jackson and Futch, 2003). Brown, C.A. and M.G. Brown. 2001. may complement and sometimes It is the antithesis of a convenience fruit, Florida citrus outlook. 3 Dec. 2004. challenge ‘Clementine’. ‘W. Murcott’ hard to peel with abundant release of . as a seedling from an open-pollinated growers call it a “sink orange” because Bureau of Citrus Budwood Registra- ‘Murcott’ tree in Morocco. The fruit it is so juicy you need to eat it over the tion. 2002. Annual report. 6 Dec. 2004. are similar in size and shape to ‘Mur- sink), but prices remain excellent for . tage of being seedless when grown ductivity of ‘Minneola’ and its extreme in isolation from compatible pollen- susceptibility to the fungal disease Castle, B., T. Hammond, and M. Kes- izers (Castle et al., 2004; Chao et al., alternaria (Alternaria alternata) make inger. 2004. W. Murcott: A new scion variety on the scene. Citrus Ind. Mag. 2005). ‘W. Murcott’ is being widely it diffi cult to overproduce. 85(5):13–14. planted in Morocco and California ‘LB8-9’ is a ‘Clementine’ x ‘Min- and is commanding excellent mar- neola’ hybrid from F.G. Gmitter’s Castle, W.S. and J.J. Ferguson. 2003. Early- ket acceptance and price as a similar program at the University of Florida. maturing sweet oranges: Research update product to ‘Clementine’, with a peak It produces a fruit and tree similar to on Earlygold, Itaborai, Ruby, and Westin maturity later than ‘Clementine’ but ‘Minneola’ but trees bear more heav- sweet oranges. 6 Dec. 2004. . somewhat overlapping in season. In ily, and this new hybrid shows limited an ongoing California trial, ‘W. Mur- susceptibility to alternaria. It may be Chao, C.T., J. Fang, and P.S. Devanand. cott’ outproduced ‘Clementine’ and slightly earlier than ‘Minneola’ and 2005. Long distance pollen fl ow in man- ‘Satsuma’ (Ferguson et al., 2000). ‘W. could permit a Thanksgiving market. darin orchards determined by AFLP Murcott’ trees have consistently been Fruit are seedy and tend to be smaller markers—Implication for seedless man- very productive when , with little than ‘Minneola’. It is expected to be darin production. J. Amer. Soc. Hort. Sci. 130:374–380. evidence of alternate bearing (C.T. released soon, offi cially for “door- Chao, unpublished data). If grown in yard” use, and the name has not been Del Monte. 2001. Del Monte fresh produce solid blocks away from other cultivars determined. expands into fresh cut citrus with leading with compatible pollen, ‘W. Murcott’ Numerous seedless triploid man- edge automation technology. 3 Dec. 2004. will set in Florida, but darins from University of Florida . crops has not been demonstrated tion along with somaclonal variants of (Castle et al., 2004). Some California ‘Valencia’ and several grapefruit culti- DeMarree, A. 2003. New Zealand strate- seedless ‘W. Murcott’ fruit are being vars that vary in season of maturity and gies for competing in a global marketplace. marketed under the trade name Delite a few other characteristics. Along with 3 Dec. 2004. . Dr. Mikeal Roose at the University of California–Riverside is using irra- Fang, D.Q. and M.L. Roose. 1997. Iden- of California–Riverside has been very diation to produce mandarin hybrids tifi cation of closely related citrus cultivars active in developing new mandarin- that are seedless even when good pol- with inter-simple sequence repeat markers. type cultivars. ‘’ is a seed- lenizers are nearby. He has interesting Theoretical Appl. Genet. 95:408–417. less mandarin hybrid recently released selections of ‘W. Murcott’ and many Ferguson, J.J. 1996. The Satsuma tanger- from this program in 1999 (Roose et other cultivars (M.L. Roose, personal ine. 6 Dec. 2004. . tasty, but has a rough skin. ‘Tahoe have numerous active citrus breeding Ferguson, L., M.L. Arpaia, T. Chao, H. Gold’, ‘Shasta Gold’, and ‘Yosemite and evaluation programs. Doubtless, Reyes, and P. Metheney. 2000. Current Gold’ were released from this program we will continue to see a parade of new fi eld evaluations of mandarin cultivars in 2003. They are all triploid hybrids cultivars throughout future years. for California. 6 Dec. 2004. . vars are large fruited, seedless, with Albrigo, L.G., D.S. Achor, and R.V. Russ. Florida Department of Citrus. 2003. Cit- a rich sweet fl avor and a tendency to 2001. Low production of Ambersweet rus reference book 2003. 3 Dec. 2004. alternate bear. They are not as easy- orange in Florida related to poor pollen . or ‘Satsuma’. Soc. Hort. Sci. 114:127–131. An important subset of the Futch, S.H. and L.K. Jackson. 2003a. Sun- Associated Press. 2001. Grapefruit mandarin-type citrus is the . burst tangerine. 6 Dec. 2004. . ‘Minneola’ is a ‘Duncan’ grapefruit x tion claims. 2 Dec. 2004. . Murcott (Honey tangerine). 6 Dec. cious to eat. Most ‘Minneola’ fruit are 2004.. numerical taxonomic study of affi nity rela- tends to make the fruit appear pear or

● July–September 2005 15(3) 505

JJuly05HT.indbuly05HT.indb 550505 66/8/05/8/05 22:24:03:24:03 PPMM WORKSHOP

Futch, S.H. and L.K. Jackson. 2003c. Fall- Nicolosi, E., Z.N. Deng, A. Gentile, S. La glo tangerine. 6 Dec. 2004. . 2000. Citrus phylogeny and genetic ori- of important species as investigated Gmitter, F.G. 1995. Origin, evolution, and by molecular markers. Theoretical Appl. breeding of the grapefruit. Plant Breeding Genet. 100:1155–1166. Rev. 13:345–363. Ragaert, P., W. Verbeke, F. Devlieghere, and Grosser, J.W., F.G. Gmitter, Jr., G.H. Flem- J. Debevere. 2004. Consumer perception ing, and J.L. Chandler. 2000. Applications and choice of minimally processed veg- of biotechnology to citrus cultivar improve- etables and packaged fruits. Quality ment at the Citrus Research and Education Preference 15:259–270. Center. Acta Hort. 535:213–220. Roose, M.L., T.E. Williams, J.W. Cameron, Hodgson, R.W. 1967. Horticultural variet- and R.K. Soost. 1999. ‘Gold Nugget’ ies of citrus, p. 431–591. In: W. Reuther, mandarin, a seedless, late-maturing hybrid. H.J. Webber, and L.D. Batchelor (eds.). HortScience 35:1176–1178. , vol. 1. Univ. of Cali- fornia. Rouse, R.E. 2000. Citrus fruit quality and yield of six Valencia clones on 16 Ipsos-Reid. 2003. Six in ten Canadians in the Immokalee Foundation Grove. Proc. report eating breakfast everyday. 6 Dec. Fla. Soc. Hort. Sci. 113:112–114. 2004. . Saunt, J. 1990. Citrus varieties of the world, an illustrated guide. 2nd ed. Sinclair Intl., Jackson, L.K. and S.H. Futch. 2003. The Norwich, U.K. Minneola tangelo. 6 Dec. 2004. . Scora, R.W. 1975. On the history and origin of Citrus. Bul. Torrey Bot. Club Lednicer, L.G. 2003. Drivers add new 102:369–375. meaning to ‘meals to go.’ 13 Dec. 2004. . orange. Rivista di Frutticultura e di Orto- fl oricoltura 63:29–32. Moore, G.A. 2001. Oranges and lem- ons: Clues to the of Citrus Williamson, J.G. 1997. The grapefruit. from molecular markers. Trends Genet. 6 Dec. 2004.. National Agricultural Statistics Service. Williamson, J.G. and L.K. Jackson. 1993. 2004. California agricultural statistics, Sweet orange. 6 Dec. 2004. . nass.usda.gov/pub/nass/ca/AgStats/ 2003cas-all.pdf>.

506 ● July–September 2005 15(3)

JJuly05HT.indbuly05HT.indb 550606 66/8/05/8/05 22:24:04:24:04 PPMM

Top View