temperature, and light intensity on the growth of lowbush and ion translocation in wheat. Physiol. . 39:305-310. ( anguslifolium A.t.) Can. J. Bot. 39:1733-1739. 21. Orchard, B. 1980. Effect of root and air temperature on growth and 16. Hussan, M.M. and F. M. Basiouny. 1984. The use of metabolic in yield of tomatoes. Acta Hort. 98:19-28. hibitors, film-forming antitranspirants, and maxijet irrigation to in 22. Pallars, I. E. Jr. 1960. Effects of temperature and humidity on foliar crease yield, improve quality and water use efficiency of . absorption and translocation of 2,4-dichloropheroxyacetic acid and Proc. Fla. State Hort. Sci. 97:348-350. benzoic acid. Plant Physiol. 35:575-580. 17. Locasio, S. J. and G. F. Warren. 1960. Interaction of soil temperature 23. Spiers, J. M. 1983. Influence of N, K and Na concentration on growth and phosphorus on growth of tomatoes. J. Amer. Soc. Hort. Sci. and element content of Tifblue' rabbiteye. HortScience 18:223- 75:601-610. 224. 18. McNairn, R. and H. B. Currier. 1968. Translocation blockageby 24. Spiers, J. M. 1978. Effects of pH level and nitrogen source on ele sieve plate callose. Plana 82:369-380. mental leaf content of 'Tifblue' rabbiteye blueberry. J. Amer. Soc. 19. Moorly, J. and C. J. Graves. 1980. Root and air temperature effects Hort. Sci. 103:705-708. on growth and yield of tomatoes and lettuce. Acta Hort. 98:29-43. 25. Webster, D. H. 1965. Heat-induced callose and lateral movement of 20. Nordin, A. J. 1977. Effect of low root temperature on ion uptake assimulates from phloem. PhD Diss., Univ. Calif., Davis.

Proc. Fla. State Hort. Soc. 98: 158-162. 1985. BREEDING BLUEBERRY FOR THE CENTRAL FLORIDA PENINSULA

P. M. Lyrene and W. B. Sherman the central peninsula of Florida. Two factors make this University of Florida, IFAS prospect interesting. One is the large potential U-pick mar Crops Department ket available around population centers in the region and Gainesville, FL 32611 the second is the possibility of producing blueberries for shipment during April, when no other fresh blueberries Additional index words. Vaccinium ashei, Vaccinium corym- are available. bosum, pentaploids, chilling requirement. 'Sharpblue' (19) is currently believed to be the best adapted to the area south of Ocala, although grower experience with blueberries in this area is not sufficient to Abstract. Wild highbush blueberries ( allow firm conclusions. For the U-pick market, where early L) occur in woodland sitesin the central Florida peninsula ripening is less important, some of thecurrently available southward to Lake Okeechobee. This suggests that commercial rabbiteye cultivars may also prove satisfactory. blueberry production should be possible in the area if suitable cultivars are developed. Two potentially profitable markets The purpose of this paper is to discuss the prospects for growing blueberries in the central Florida peninsula are the local U-pick market and the April fresh-fruit shipping market. Consistent production of blueberries during early to and to describe some breeding strategies that could result in cultivars that would perform better in the area. mid April will require production sites where the last killing frost is 15 Feb. or earlier. Cultivars for this purpose must Blueberry Cultural Problems In The Central Florida Peninsula early and have short flowering-to-ripening intervals. For the U-pick market, high yields are more important than Climate. The climate between 1 Nov. and 1 Mar. is the early ripening. Possible selections for U-pick production, in primary reason for uncertainty regarding the performance clude rabbiteye blueberries (V. ashei, Reade) selected for re of north-Florida blueberry cultivars in the central Florida sistance to mild-winter-induced fruit drop and fruitful pentap- peninsula. The 2 cultivated types, highbush and rabbiteye, loid hybrids, which combine the high plant vigor of therab are in north Florida. Flower buds ordinarily be biteye with the highbush ability to set fruit well following come visible in the leaf axils during Sept., Nov., and Dec. insufficient chilling. The begin to abscise after the first killing frost, and usually lose most of their leaves by 1 Jan. North- Blueberry production is expanding rapidly in North Florida blueberry cultivars have a chilling requirement of America. In 1935 there were fewer than 1,000 acres of about 200 to 300 hr below 45°F for 'Sharpblue' and 200 to cultivated blueberries on the continent, but estimates in 500 hr for various rabbiteye cultivars. Plants that have been 1983 placed combined cultivated acres of highbush and inadequately chilled usually show delayed bud break in the rabbiteye blueberries at 39,050 (15). Florida's acreage of spring. Some buds may open and grow, while others on cultivated blueberries has increased from fewer than 200 the same stem remain dormant, flowering may be delayed to almost 1,000 acres within the past 10 years, and the rate a month or more, and the flowering period may be pro of expansion is accelerating. Almost all of this acreage has longed. ripening also will begin later than normal been planted from Ocalanorthward, where current cul and extend over a longer period. Plants may lose vigor and tivars are best adapted and have been tested most exten die if underchilling is severe and occurs for several years. sively (16,17,18). Poor fruit set is another effect of insufficient chilling Although their fruit is too small for commercial use, at (10). This is very important with many rabbiteye cultivars least 3 species of native wild blueberries, V. darrowi Camp, but much less so with highbush. Following mild winters, V. myrsinites Lam., and V. corymbosum are abundant on acid some rabbiteye cultivars flower normally, but set few fruit, soils as far south as Lake Okeechobee (1,11,12,20). This the young abscising shortly after petal fall. This indicates that blueberry cultivation should be possible in phenomenon is poorly understood, and it it is not clear why the problem is so much more severe with rabbiteyes University of Florida Journal Series Number 6841. than with highbush. The severity of mild-winter-induced

158 Proc. Fla. State Hort. Soc. 98: 1985. fruit drop varies considerably among rabbiteye cultivars. veloped with a bloom-to-ripe interval as short as 50 days, Other problems with climatic adaptation might be an dependable berry production in early April will probably ticipated when north-Florida blueberry cultivars are grown require cultivars that flower earlier than 'Sharpblue'. Such south of their region of best adaptation. During a very cultivars would not be adapted to north Florida because mild winter, vigorous plants might continue to grow the danger of crop loss from spring frost would be too throughout the winter without losing their leaves. This great. Table 1 shows for selected cities in north and central could result in nonsynchronous flowering. After the nor Florida the date after which chances are 80% that temper mal fruit harvest in May, vigorous 'Sharpblue' at Gaines atures lower than 28°F will not occur (14). This is the ap ville sometimes flower a second time during the summer proximate date on which a grower might wish his blueber and fall. The resulting fruit is usually destroyed by frost ries to flower if he were growing for the early market and in November. When grown farther south, 'Sharpblue' did not have overhead irrigation for frost protection. might ripen this fruit during the winter if protected from Overhead irrigation at 0.2 acre-inches/hr could protect frost. and fruit down to 22°F if winds were light. With 'Sharpblue' and other low-chilling highbush cultivars overhead irrigation, optimum flowering dates would be could be somewhat vulnerable to frost in central Florida. earlier than those shown in Table 1. If the first part of the winter season was cold, and warm Care must be taken in using Table 1 due to localized weather followed during Jan. and early Feb., the plants variations in last-frost dates. A location even within a few could flower by 10 Feb. and be vulnerable to spring frost. miles of the weather station may differ significantly in frost The opposite problem with trying to produce early-season occurrences because of local topographic features.The im berries would occur in years when flowering and fruiting portance of local variation is illustrated by Sanford and dates were delayed excessively due to lack of chilling. Deland (Table 1), which are less than 20 miles apart but The greatest challenge in trying to breed blueberries differ in average date of last 28°F temperature by 26 days. for the central peninsula is not lack of chilling per se, since Longtime residents often know from experience whether low-chilling genes are available in native blueberries. The their locations are warmer or colder than official recording greatest challenge is the high year-to-year variability in the locations. amount of chilling received and the variability in timing of Average temperatures for December, January, and the chilling period. Native species cope with this variability February indicate how much chillling plants receive. Areas by coupling evergreen growth habit with late flowering or with temperatures averaging 59.0°F or below from 1 Dec. by having a long flowering period. Neither strategy is very through 28 Feb. should be able to get good yields on low- satisfactory for a breeder if his goal is to produce early-ri chill rabbiteye cultivars in most years. This expectation is pening blueberries with synchronous ripening. based on several years' observations of blueberry farms in Other cultural problems. Other cultural problems with the Ocala area where mean winter temperatures are near blueberries in the central Florida peninsula are similar to 59°F. The highbush cultivar 'Sharpblue' would receive those experienced in North Florida (9). Some soils are un adequate chilling most winters even in somewhat warmer suitable for blueberries due to high pH (above 5.5); others areas. are droughty because of sandy texture; others have poor A location without spring freezes is only one prerequis drainage. Furthermore, some soils that seem best for ite for production of early April blueberries. Cultivars that blueberries are associated with frost pockets. flower early and have short flowering-to-ripening intervals Birds are usually a serious problem in small blueberry are also necessary. Both highbush and rabbiteye blueber plantings, and since first plantings in new areas are usually ries have much genetic variation in flowering date, and small, bird damage could be severe. early-flowering cultivars could be developed for each group. With respect to flowering-to-ripening interval, Strategies For Developing Blueberry Cultivars however, highbush are substantially earlier than rabbiteyes For the Central Florida Peninsula (Table 2), and cultivars designed for April production in Two markets can be identified for central peninsula central Florida will probably be highbush. blueberries: the early shipping market, for which the ber To study variability in flowering-to-ripening interval, ries would ideally ripen during April, and the U-pick mar observations were made on 29 tetraploid highbush cul ket, for which time of ripening is less critical. In theory, tivars and selections, 5 tetraploid F2 highbush x V. elliottii the same cultivars could serve both purposes, but as a prac Chapman, hybrids, and 30 V. ashei cultivars and selections tical matter, higher-yielding cultivars could be developed which were used as seed parents in the blueberry breeding for U-pick if requirements for early ripening and good program at Gainesville in the spring of 1985. All plants shipping qualities are relaxed. were vigorous and had been potted and received at least 4 Early-ripening cultivars for shipment. The first fresh weeks of 40°F temperatures before they were moved to a blueberries in the northern hemisphere are shipped each greenhouse for flowering. Each plant was pollinated with year about 1 May and come from the 'Sharpblue' in the compatible pollen, primarily rabbiteye pollen onto the rab Gainesville-Ocala area. The volume of fresh blueberries biteyes and highbush pollen onto the highbush and high available before 1 June is quite small, and fresh-market bush x V. elliottii selections. Flowers were emasculated and prices from 1 May to 1 June are comparatively high. How hand pollinated as described by Galletta (5). Plants were ever, production for the May market is increasing rapidly pollinated between 22 Feb. and 5 Mar., and the date of in north Florida, and prices can be expected to fall some pollination was recorded. A minimum of 22 flowers was what in the future. 'Sharpblue' grown in the field in north pollinated for each plant. The greenhouse was heated or Florida usually requires 60 to 65 days to go from open cooled to keep the temperature between 40° and 90°F. The flower to ripe berry. Although cultivars could be de date on which the first berries ripened on each plant was

Proc. Fla. State Hort. Soc. 98: 1985. 159 Table 1. Average daily temperatures, 1 Dec. to 28 Feb., and average date after which the probability of a temperature 28° F or lower is 20% for selected cities in north and central Florida.2

Ave. daily temperature Last 28°F temp Location Elevation (20% probability December January February December (ft) of a later through occurrence) February

1. St. Petersburg 8 0/00y 63.4 61.9 62.9 62.7 2. Sanford 17 1/21 61.0 59.6 60.5 60.4 3. Melbourne 10 1/21 62.9 61.5 61.8 62.1 4. Clermont 125 1/22 60.6 59.5 61.0 60.4 5. Tarpon Springs 8 1/22 60.8 59.2 60.4 60.1 6. Avon Park 133 1/25 63.1 61.8 63.0 62.6 7. Bar tow 125 1/28 62.0 60.9 62.2 61.7 8. Inverness 50 2/03 59.6 58.4 59.7 59.2 9. Titusville 30 2/06 61.6 60.2 61.0 60.9 10. Plant City 121 2/06 62.3 61.2 62.3 61.9 11. Wauchula 119 2/08 62.4 61.5 62.5 62.1 12. Lake Alfred 145 2/08 60.8 59.6 60.8 60.4 13. Arcadia 63 2/11 62.5 61.6 62.5 62.2 14. Brooksville 240 2/11 60.8 59.4 60.6 60.3 15. Palatka 20 2/12 58.9 57.5 59.1 58.5 16. Jacksonville Beach 10 2/14 56.8 54.7 56.0 55.8 17. Ocala 90 2/17 59.5 58.3 59.8 59.2 18. Deland 25 2/19 59.0 58.0 59.0 58.7 19. Gainesville 86 2/24 57.8 56.4 57.8 57.3 20. Madison 190 2/27 54.5 53.3 55.5 54.4 21. Lake City 195 2/28 55.1 53.6 55.5 54.7 22. Quincy 245 3/04 53.5 51.9 53.8 53.1 23. Monticello 148 3/08 52.5 51.2 53.2 52.3 24. Chipley 130 3/09 52.9 51.3 53.7 52.6 25. Milton 217 3/10 53.0 51.2 53.7 52.6 26. Cross City 42 3/10 54.5 53.0 54.9 54.1 27. Jasper 147 3/12 53.4 52.1 54.4 53.3 28. Niceville 60 3/12 51.5 49.3 51.5 50.8 29. De Funiack Springs 230 3/17 52.8 51.1 53.8 52.7

'Data taken from reference 14 and are averages for the years 1951-80. Probability is less than 20% for winter. recorded. Berries were considered ripe when fully black ing to ripening and favor earlier ripening of blueberries or blue. grown farther south. A study with 4 cultivars of northern The flowering-to-ripening intervals measured in this highbush, hand-pollinated in a greenhouse in Maryland, test ranged from 42 to 80 days (Table 2). The 30 earliest-ri showed that fruit ripened an average of 25 days earlier in pening plants were all highbush or highbush X V. elliottii a greenhouse maintained between 61 and 81°F compared ¥x selections. The latest-ripening 28 plants were all V. ashei. to plants in a second greenhouse at 46 to 76°F (7). A similar The earliest highbush selection ripened in 14 fewer days study with lowbush blueberry (V. angustifolium Ait.) in than the earliest rabbiteye. Canada showed average intervals from anthesis to fruit Two points should be emphasized regarding the data maturity of 50.2 days and 66.2 days for greenhouses main in Table 2. First, since the sun heated the greenhouse to tained at dan/night temperatures of 70760° and 60750°F, temperatures considerably above average daytime spring respectively (6). The average daily March temperatures for temperatures in Gainesville, the flowering-to-ripening in several cities in Florida are: Plant City 67.2°; Clermont tervals measured in the greenhouse were shorter than 66.8°, Ocala 65.9°, Gainesville 63.9°, Madison 62.2°, and would be expected under field conditions. Higher temper Milton 59.9° F (14). The differences between the northern atures can greatly reduce the flowering-to-ripening inter and southern stations seem great enough to produce dif val in blueberries (6,7). Second, most of these clones had ferences in flowering-to-ripening interval of at least several been selected as parents partly because they ripened early, days. since early ripening is a major objective of the Florida Numerous cultivars, selections, and native species have breeding program. 'Climax' and 'Bonita', which were been used in the blueberry breeding program at Gaines among the later of the rabbiteye clones tested in the ville in the past decade. Those that have shown the most greenhouse, are along with 'Aliceblue', 'Beckyblue', and promise in breeding low-chilling, early ripening, commer 'Premier' the earliest-ripening of the released rabbiteye cial-quality blueberry cultivars for central Florida are listed cultivars (8). Thus, even though rabbiteye selections with in Table 3. It is hoped that test selections derived from this shorter berry-development periods are being obtained material can soon be grown at several locations in central through breeding, the earliest highbush selections are still Florida. substantially earlier than the earliest, rabbiteyes. Breeding U-pick cultivars for central Florida. Blueberries Temperatures during the fruit development, period are have been widely planted as a U-pick crop in south Georgia higher in south-central Florida than farther north in the and north Florida. Few have been planted south of Ocala state. This would tend to shorten the period from flower because of uncertainty about the performance of north

160 Proc. Fla. State Hort. Soc. 98: 1985. Table 2. Number of days from first pollination to first ripe fruit on high- Florida cultivars in the central Florida peninsula. The pop bush and rabbiteye selections hand-pollinated in the greenhouse at ulation between Ocala and Lake Okeechobee is large Gainesville, Spring, 19857. enough to support several hundred acres of U-pick blueberries if the berries can be grown at a reasonable Days from Cross pollination price. to ripe fruit Female Pollen Source Type of Crossy Almost all U-pick blueberries grown in north Florida are rabbiteyes, because of the higher yields and greater 42 F84-121 x Harrison (HxE) x H 45 F81-15xNC1146 (HxE) x H vigor of this species compared to highbush blueberries. 45 NC1688x Murphy HxH Rabbiteyes grow vigorously on suitable soils in central Flor 47 F78-15xUS245 HxH ida south of Ocala and their primary problem in this area 47 F6-19xNC1688 HxH has been poor fruiting after mild winters, which results 47 Flordablue x Bluechip HxH 48 FlordabluexSF12L HxH from berry abscision approximately 3 weeks after pollina 48 Flordablue x NCI074 HxH tion. One way to obtain satisfactory U-pick blueberry cul 49 Harrison x 72-1 HxH tivars for central Florida would be to develop rabbiteye 49 NC1688xUS245 HxH cultivars that yield well after mild winters. Observations at 49 NC1688xSF12L HxH Gainesville indicate much variability among rabbiteye cul 49 NC1688xNC1146 HxH 49 F83-135xNC1146 HxH tivars and selections for fruit set after mild winters. The 49 F6-19xCH89-2 HxH U-pick cultivar problem in the central Florida peninsula 50 US245xF72-l HxH might be solved by a simple replicated test of 20 or 30 50 Sharpblue x Harrison HxH rabbiteye cultivars and advanced selections at several loca 51 F81-15x Murphy (HxE) x H 51 Flordablue x CH89-2 HxH tions in the area. Among the rabbiteye cultivars that would 51 F5-12xNC1146 HxH be recommended for trial, based on their performance 51 F5-12xSF12L HxH after mild winters at Gainesville, are 'Climax', 'Bluebelle', 51 Flordablue x NCI 146 HxH 'Bonita', 'Chaucer', 'Choice', 'Beckyblue', Towderblue', 51 F5-12xUS239 HxH 'Brightwell', and 'Southland;. Until further information is 52 F78-15xNC1688 HxH 52 F84-122xNC1146 (HxE) x H received, none of these cultivars can be recommended for 54 F84-149xNC945 (HxE) x H reliable yields in areas with 1 Dec. through 28 Feb. average 54 F3-8xNC1688 HxH temperatures exceeding 59°F (see Table 1). 54 F3-8xF81-15 H x (HxE) Another possibility for developing vigorous U-pick 55 F3-8xNC1074 HxH 55 AvonbluexNC1146 HxH blueberry cultivars for the central Florida peninsula lies in 55 AvonbluexSF12L HxH pentaploid highbush x rabbiteye hybrids. Such pentaploid 56 F84-110xF84-97 AxA hybrids have been produced several times in the past by 56 F84-102xasheicomp.x AxA breeders with various objectives (13). In some cases, the 57 F84-158xNC1074 HxH 57 Murphy xF81-15 HxH hybrids have had low fertility. In other cases they have 58 F3-8xNC1074 HxH been quite fruitful when cross-pollinated with either high 59 F5-12xNC1688 HxH bush or rabbiteye pollen (2,3,4). The fruit of the hybrids 60 F84-126xF82-61 AxA has usually been black, even when both parents were blue- 60 F84-126xBrightwell AxA fruited, and the berries have had very few seeds. Of the 60 F84-92 x ashei comp. AxA 61 F84-91 x ashei comp. AxA 100 or so pentaploid hybrids grown in Gainesville, most 62 F84-98 x ashei comp. AxA have been quite fruitful if open-pollinated in the presence 62 F84-108x ashei comp. AxA of rabbiteyes and highbush, and fruit has been about as 63 F84-110xF84-107 AxA large as for comparable highbush x highbush or rabbiteye 63 F84-112 x ashei comp. AxA x rabbiteye seedlings. 64 F84-99 x ashei comp. AxA 64 BonitaxF80-150 AxA Pentaploid hybrids are suggested as possible U-pick 65 Climax x F84-106 AxA cultivars for central Florida because they are highly vigor 65 Climax x F84-92 AxA ous, resembling the rabbiteye parent in this respect, and 65 F84-93 x ashei comp. AxA because most highbush cultivars fruit very consistently at 66 F80-150xF81-31 AxA 66 F84-88 x ashei comp. AxA Gainesville, even after their chilling requirements have 67 BonitaxF82-61 AxA been only partially met. Highbush seedlings frequently 68 Climax x F82-61 AxA overfruit in north Florida, resulting in small berries, de 69 F84-86 x ashei comp. AxA layed ripening, and loss of vigor. If the excellent fruit set 69 F82-61 x NC2144 A x (AxC) 69 F84-111 x ashei comp. AxA capabilities of highbush are expressed even partially in ¥} 71 F84-116 x ashei comp. AxA hybrids with rabbiteyes, pentaploids might fruit more de 71 Climax x NC2144 A x (AxC) pendably than rabbiteyes in the central peninsula. If pen 72 Climax x F84-46 AxA taploids prove feasible, they would have to be interplanted 75 F84-101 x ashei comp. AxA with highbush or rabbiteye cultivars, because the pollen of 76 Bluebelle x F84-48 AxA 76 Brightwell x F84-46 AxA pentaploids has low viability. Use of highbush x rabbiteye 76 F84-117 x ashei comp. AxA pentaploids as U-pick cultivars would require that consum 80 F84-85 x ashei comp. AxA ers be willing to accept shiny black blueberries. Black blueberries would probably be more acceptable in U-pick 'Date of pollination ranged from 22 Feb. through 5 Mar. depending on the plant. At least 22 flowers were pollinated for each cross. markets, where they could be sampled before purchase, yH x H means highbush x highbush. than in retail markets, where dark color is taken as an HxE means highbush x V. elliottii tetraploid F! hybrid. indication of lack of freshness. The low seediness of pen AxC means V. ashei x V. constablaei F, hybrid. taploids would be a positive quality factor. xAshei comp. means a composite of pollen from several V. ashei selections. Proc. Fla. State Hort. Soc. 98: 1985. 161 Table 3. Promising germplasm sources for breeding early-ripening, low- Literature Cited chill highbush blueberry cultivars for the central Florida peninsula. 1. Camp, W. H. 1945. The North American blueberries with notes on NO. Germplasm Comments other groups of Vacciniaceae. Brittonia 5:203-275. 2. Darrow, G. M., W. H. Camp, H. E. Fisher, and H. Dermen. 1944. 1. Florida highbush cultivars and 1. High fruit quality, low Chromosome numbers in Vaccinium and related groups. Bui. Torrey breeding lines (Sharpblue, chilling requirement, early Bot. Club 71:498-516. Flordablue, etc.) ripening. 3. Darrow, G. M., E. B. Morrow, and D. H. Scott. 1952. An evaluation 2. North Carolina and USDA 2. Highfruit quality, high to of interspecific blueberry crosses. Proc. Amer. Soc. Hort. Sci 59:277- highbush cultivars and medium chilling requirement. 282. breeding lines Good hybrid vigor in crosses 4. Darrow, G. M., D. H. Scott, and H. Dermen. 1954. Tetrapolid with Florida highbush. blueberries from hexaploid x diploid species crosses. Proc. Amer. 3. 3. A native north-Florida Soc. Hort. Sci. 63:266-270. blueberry. Very early 5. Galletta, G. J. 1975. Blueberries and cranberries. In: J. Janick and J. blooming and ripening. Berry N. Moore (eds.), Advances in fruit breeding. Purdue Univ. Press, very small. F[ hybrids and West Lafayette, Ind. backcrosses to highbush 6. Hall, I. V. and L. E. Aalders. 1968. Fruit set and berry development cultivars are highly of lowbush blueberry as affected by temperature. Can. J. Plant Sci. vigorous. Some BCj seedlings 48:321-322. may be cultivar quality. 7. Knight, R. J., Jr. and D. H. Scott. 1964. Effects of temperatures on 4. Wild north-Florida, Provide good vigor and self- and cross-pollination and fruiting of four highbush blueberry south-Georgia tetraploid adaptation in hybrids with varieties. Proc. Amer. Soc. Hort. Sci. 85:302-306. highbush (V. corymbosum) highbush cultivars. Low to 8. Lyrene, P. M. and T. E. Crocker. 1984. Florida blueberry Handbook. medium chilling requirement. Fla. Coop. Ext. Serv. Cir. 564. Univ. Florida, Gainesville. Some BC, seedlings have 9. Lyrene, P. M. and T. E. Crocker. 1984. Florida blueberry Handbook. cultivar quality. Fla. Coop. Ext. Serv. Cir. 564. Univ. of Florida, Gainesville. 5. Wild central Florida diploid 5. Very low chilling. Good 10. Lyrene, P. M. and T. E. Crocker. 1983. Poor fruit set on rabbiteye highbush (V. corymbosum) upright growth habit but blueberries after mild winters: possible causes and remedies. Proc. berries very small. Fla. State Hort. Soc. 96:195-197. 6. Wild V. darrowi from central 6. Evergreen, very low chilling 11. Lyrene, P. M. and W. B. Sherman. 1977. Breeding blueberries for Florida sand scrub. Tallest requirement. Flowers and Florida: Accomplishments and goals. Proc. Fla. State Hort. Soc. selections and natural hybrids ripens late and over a long 90:215-217. with diploid V. corymbosum seem period. Lowbush, colonial 12. Lyrene, P. M. and W. B. Sherman. 1981. Breeding value of southern most useful. growth habit undesirable and highbush blueberry. HortScience 16:528-529. usually manifested by F, 13. Moore, J. N., D. H. Scott, and H. Dermen. 1964. Development of a hybrids. Drought resistant decaploid blueberry by colchicine treatment. Proc. Amer. Soc. Hort. and ornamental. Sci. 84:274-279. 14. National Oceanic and Atmospheric Administration. 1985. Climatog- raphy of the No. 20, Climatic summaries for selected sites, Florida, 1951-80. 15. Nelson, J. W. 1984. Estimated 1983 north american blueberry ac reage, p. 6-7. In: T. E. Crocker and P. Lyrene (eds.). Proc. Fifth In summary, it is likely that blueberries will someday North Amer. Blueberry Res. Workers Conference, Univ. of Florida, be produced on a commercial scale in the central Florida Gainesville. 16. Sharpe, R. H. and G. M. Darrow. 1959. Breeding blueberries for the peninsula as far south as Lake Okeechobee, both to take Florida climate. Proc. Fla. State Hort. Soc. 72:308-311. advantage of excellent prices for Apr. berries in northern 18. Sharpe, R. H. and W. B. Sherman. 1971. Breeding blueberries for markets and to satisfy the large potential U-pick market. low chilling requirement. HortScience 6:145-147. How fast this industry develops depends to a large extent 19. Sharpe, R. H. and W. B. Sherman. 1976. Flordablue and Sharpblue. Fla. Agr. Expt. Sta. Cir. S-240. on how quickly new cultivars can be developed and tested 20. Ward, D. B. 1974. Contributions to the flora of Florida-b, Vaccinium in the area. {). Castanea 39:191-205.

Proc. Fla. State Hort. Soc. 98: 162-164. 1985.

SURVEY OF BLUEBERRY ACREAGE IN FLORIDA

T. E. Crocker and P. M. Lyrene mates have been made as to the acreage of blueberries in Fruit Crops Department, IFAS the State. In the spring of 1985, a survey was made to deter University of Florida, Gainesville, FL 32611 mine how many acres of commercial blueberries are grown in each county in Florida. Both U-Pick and acres intended for Additional index words. Vaccinium ashei, Vaccinium corym fresh-fruit shipment were included in the survey. The total bosum. acreage of blueberries in Florida was found to be 1057.7. The area west of the Apalachicola River had 285 acres, the area south of Marion County had 87 acres, and the section between Abstract. Blueberries (Vaccinium spp.) have been grown in the first 2 areas had 685.7 acres. The size of the plantings Florida for many years. During the last few years, many esti varied from one-quarter acre to over 200 acres.

162 Proc. Fla. State Hort. Soc. 98: 1985.