Progress 10/01/07 to 09/30/13

Outputs
Target Audience: The primary target audience for this project are blueberry breeders, research and extension scientists working in Vaccinium production, and blueberry producers in the southeastern United States. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Four graduate students and two postdoctoral research associates have been trained in plant breeding and blueberry culture during this project. Three international scholars have completed research internships. How have the results been disseminated to communities of interest? Presentations at the semi-annual Florida Blueberry Growers Association (FBGA) meetings, and the Southeastern Regional Fruit and Vegetable Conference have been the main avenues to reach industry clientele and producers. Presentations about new cultivars, UF cultivars used in research trials, and breeding priorities have reached at least 2,000 people based on estimated attendance at the FBGA meetings alone (2009-2013). In many cases, presentation topics have been followed up by popular press articles to reach a wider audience. Demand for UF blueberry cultivars has remained high as evidenced by the relatively stable level of royalty returns per year in a difficult economic environment. Current cultivar information and results of cultivar use in research trials were provided at three in-service trainings and three seminars attended by Extension specialists and county agents. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Blueberry cultivars that are adapted to warm areas such as Florida make it possible to harvest fresh blueberries from March 20 to May 20 in the northern hemisphere and from September 20 through November 20 in the southern hemisphere. Without low-chill cultivars such as those being bred in Florida, only frozen blueberries or blueberries long held in controlled atmosphere storage would be available during these four months. Recent cultivar releases from the UF blueberry breeding program have an impact by enabling greater production range by more consistent production in extremely low-chill areas (‘FL96-43’, ‘FL02-40’, and ‘FL04-235’), and incorporation of traits such as upright growth, loose clusters, high yield, and early fruiting into a cultivar suitable for mechanized harvest for fresh market (‘FL01-173’). Cultivars such as ‘Farthing’ and ‘Sweetcrisp’ have also performed well in machine harvest trials due to firm fruit texture. Research into the breeding value of interspecific hybrids has the potential to uncover valuable traits and phenotypes for inclusion in future cultivars. In particular, V. darrowii, and V. arboreum, native Florida blueberries, are an important source of adaptation for survival and productivity in Florida. Using a combination of flow cytometry, cytogenetics, morphological characteristics, and genomics, we have been able to better identify true hybrids between these interspecific crosses. Collectively, the products developed in the breeding program have continued to support expansion of worldwide blueberry production. The cultivars developed in this project have positively impacted growers and communities in Florida by providing a high-value alternative to existing horticultural crops produced in the state.

Publications

• Type: Journal Articles Status: Published Year Published: 2013 Citation: Volk, G.M., J.W. Olmstead, C.E. Finn, and J. Janick. 2013. The outstanding fruit cultivar award: A 25 year retrospective. HortScience 48:4-12.
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Gilbert, J.L., M.L. Schwieterman, T. A. Colquhoun, D.G. Clark, and J.W. Olmstead. 2013. Potential for increasing southern highbush blueberry flavor acceptance by breeding for major volatile components. HortScience 48:835-843.
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Takeda, F., G. Krewer, C. Li, D. MacLean, and J.W. Olmstead. 2013. Techniques for increasing machine harvest efficiency in highbush blueberry. HortTechnology 23:430-436.
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Sargent, S.A., A.D. Berry, J.G. Williamson, and J.W. Olmstead. 2013. Postharvest quality of mechanically and hand-harvested southern highbush blueberry fruit for fresh market. HortTechnology 23:437-441.
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Olmstead, J.W., H.P. Rodriguez-Armenta, and P.M. Lyrene. 2013. Using sparkleberry as a genetic source for machine harvest traits for southern highbush blueberry. HortTechnology 23:419-424.
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Colquhoun, T.A., M.L. Schwieterman, J.L. Gilbert, E.A. Jaworski, K.M. Langer, C.R. Jones, G.V. Rushing, T.M. Hunter, J. Olmstead, D.G. Clark, and K.M. Folta. 2013. Light modulation of volatile organic compounds from petunia flowers and select fruits. Postharvest Biology and Technology 86:37-44.
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Olmstead, J.W. 2013. Progress in breeding highbush blueberry cultivars adapted to machine harvest for the fresh market. HortScience 48(9):S80. (Abstr.).
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Nunez, G.H., J.W. Olmstead, and R.L. Darnell. 2013. Plant architecture of Vaccinium genotypes as influenced by soil characteristics. HortScience 48(9):S152-153. (Abstr.).
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Gilbert, J.L., M.L. Schweiterman, T.A. Colquhoun, D.G. Clark, and J.W. Olmstead. 2013. Genetic and environmental variation in southern highbush blueberry flavor components. HortScience 48(9):S175-176. (Abstr.).
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Nunez, G.H., C.L. Harmon, A. Vitoreli, R.L. Darnell, and J.W. Olmstead. 2013. Friend or foe? Bacterial nitrate and iron reduction in the roots and rhizosphere of Vaccinium corymbosum and Vaccinium arboreum. HortScience 48(9):S278. (Abstr.).
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Itle, R.A., T. Branaman, S.R. Marino, and J.W. Olmstead. 2013. Estimating the chilling requirement of southern highbush blueberry breeding selections. HortScience 48(9):S311-312. (Abstr.).
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Rodriguez-Armenta, H.P. and J.W. Olmstead. 2013. Identification of sparkleberry (Vaccinium arboreum) genome introgression with microsatellite markers developed in highbush blueberry. HortScience 48(9):S312. (Abstr.).
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Sargent, S., J.G. Williamson, A.D. Berry, and J.W. Olmstead. 2013. Effect of harvest delay of southern highbush blueberry on resistance to impact and storage quality. HortScience 48(9):S400. (Abstr.).
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Itle, R.A., C. Cellon, K.M. Guererro, M.J. Weiss, W. Cobb, G.E. Covarrubias, W.R. Collante, and J.W. Olmstead. 2013. Fruit quality measurements in a segregating blueberry population: Plant breeding training for undergraduates. HortScience 48(9):S416. (Abstr.).

Progress 10/01/11 to 09/30/12

Outputs
OUTPUTS: Germplasm developed during the reporting period resulted from 191 different hybridizations utilizing Vaccinium corymbosum, V. darrowii, V. elliottii, V. arboreum, V. stamineum and various interspecific hybrids between the species. Nearly 200 clonally propagated advanced selections identified during the 2011 season were planted during 2012 for evaluation, and 20 genotypes were identified for advancement into final-stage selection. From 2011 crosses, over 20,000 seedlings were planted for evaluation. Grower-cooperator trials established in central and south-central Florida to evaluate advanced selections in very low chill environments were used to develop a rapid cut-cane assay for chilling requirement. Six blueberry cultivars and selections were evaluated at four different harvest dates for total sugars, organic acids, and volatile aroma content. Consumer taste panels ranked liking for each harvest date. We continued to evaluate hybrids between V. corymbosum and V. arboreum plants for pollen fertility, vegetative, and reproductive characteristics, and fruit quality. Two backcross populations between these hybrids and cultivated southern highbush cultivars were evaluated for fruit quality. We continued collaboration with the USDA-ARS group in Fort Pierce, FL to assess blueberry fruit texture by trained consumer panels. A cross between a northern and southern highbush cultivar was evaluated for chilling requirement, vegetative and reproductive traits, and fruit quality in two locations (Georgia and Florida) to determine genetic loci contributing to the traits. Two research plots were evaluated for potential differences in vegetative and reproductive characteristics between cultivars propagated by tissue culture or softwood cuttings under Florida production conditions. Breeding program goals, methodology, and cultivar descriptions were disseminated through grower meetings and field days, update articles in the Florida Blueberry Growers Association quarterly newsletter, other trade publications, and published cultivar descriptions. Research program findings were disseminated to scientists through participation in scientific meetings and scientific publications. PARTICIPANTS: PROJECT: James Olmstead (Principal Investigator), Paul Lyrene (Emeritus Professor), David Norden (Research Coordinator), Werner Collante (Laboratory Manager). COLLABORATORS: Jeff Williamson (Univ. of FL, Extension Specialist), Steve Sargent (Univ. of FL, Postharvest Specialist), Rebecca Darnell (Univ. of FL), Anne Plotto (USDA-ARS), Elizabeth Baldwin (USDA-ARS), Charles Sims (Univ. of FL), Jim Hancock (Michigan State Univ.), Lisa Rowland (USDA-ARS), Nahla Bassil (USDA-ARS), Chad Finn (USDA-ARS), Allan Brown (NC State Univ.), Alto Straughn (Straughn Farms), Ken Patterson (Island Grove Agricultural Products), Jerry Mixon (Mixon Family Farms), James Miller (Miller Blueberry Plantation). TRAINING AND PROFESSIONAL DEVELOPMENT: Kendra Blaker (PhD Student), Hilda-Patricia Rodriguez-Armenta (PhD Student), Gerardo Nunez (PhD Student), Jessica Gilbert (PhD Student), Silvia Marino (M.S. Student), Rachel Itle (Postdoctoral Associate), Sarah Taber (Postdoctoral Associate). TARGET AUDIENCES: The primary target audience for this project are blueberry breeders, research and extension scientists working in Vaccinium production, and blueberry producers in the southeastern United States. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Blueberry cultivars that are adapted to warm areas such as Florida make it possible to harvest fresh blueberries from March 20 to May 20 in the northern hemisphere and from September 20 through November 20 in the southern hemisphere. Without low-chill cultivars such as those being bred in Florida, only frozen blueberries or blueberries long held in controlled atmosphere storage would be available during these four months. Recent cultivar releases from the UF blueberry breeding program have an impact by enabling greater production range by more consistent production in extremely low-chill areas (FL96-43, FL02-40, and FL04-235), and incorporation of traits such as upright growth, loose clusters, high yield, and early fruiting into a cultivar suitable for mechanized harvest for fresh market (FL01-173). Cultivars such as Farthing and Sweetcrisp have also performed well in machine harvest trials due to firm fruit texture. Research into the breeding value of interspecific hybrids has the potential to uncover valuable traits and phenotypes for inclusion in future cultivars. In particular, V. darrowii, and V. arboreum, native Florida blueberries, are an important source of adaptation for survival and productivity in Florida. Using a combination of flow cytometry, cytogenetics, and morphological characteristics, we have been able to better identify true hybrids between these interspecific crosses. Collectively, the products developed in the breeding program have continued to support expansion of worldwide blueberry production. In trained panel evaluation of blueberry fruit texture, average panel ratings followed closely with subjective breeder rankings for firmness, and panelists were able to clearly distinguish cultivars and selections ranked during breeding evaluations as crisp fruit. Each genotype evaluated by the trained panel was measured for fruit firmness and skin texture and correlations between flesh firmness, skin puncture force and sensory evaluations revealed the crisp texture to be only moderately correlated with firmer fruit. Research into flesh texture and its potential to be used for more consistent high-quality production of fresh fruit under mechanized harvest strategies will be critical for future growth of the Florida blueberry industry.

Publications

• Itle, R.A., S. McCallum, J. Graham, J.W. Olmstead, W.R. Collante, N.V. Bassil, A.F. Brown, E.J. Buck, C.E. Finn, J.F. Hancock, and L.J. Rowland. 2012. QTL mapping in an F1 tetraploid blueberry (Vaccinium corymbosum L.) population. HortScience 47(9):S145. (Abstr.)
• Marino, S.R., J.G. Williamson, and J.W. Olmstead. 2012. Reproductive growth and yield of three southern highbush blueberry cultivars obtained from micropropagation and softwood cuttings in two Florida locations. HortScience 47(9):S135. (Abstr.)
• Marino, S.R., J.G. Williamson, and J.W. Olmstead. 2012. Vegetative growth of southern highbush blueberry cultivars obtained from micropropagation and softwood cuttings in two Florida locations during the first two growing seasons in the field. HortScience 47(9):S328. (Abstr.)
• Nunez, G.H., R.L. Darnell, and J.W. Olmstead. 2012. Root morphology of Vaccinium spp. in response to iron concentration. HortScience 47(9):S408. (Abstr.)
• Rodriguez-Armenta, H.P., P. Lyrene, and J.W. Olmstead. 2012. Phenotypic characterization of the first backcross generation between southern highbush blueberry and Vaccinium arboreum. HortScience 47(9):S146. (Abstr.)
• Du, X., J. Olmstead, and R. Rouseff. 2012. Comparison of fast gas chromatography-surface acoustic wave (FGC-SAW) detection and GC-MS for characterizing blueberry cultivars and maturity. Journal of Agricultural and Food Chemistry 60:5099-5106.
• Lyrene, P.M. and J.W. Olmstead. 2012. The use of inter-sectional hybrids in blueberry breeding. International Journal of Fruit Science 12:269-275.
• McCallum, S., M. Woodhead, L. Jorgensen, S. Gordon, R. Brennan, J. Graham, C.A. Hackett, L.J. Rowland, D.J. Bell, J.F. Hancock, J.W. Olmstead, and N.V. Bassil. 2012. Developing tools for long term breeding of blueberry germplasm for UK production. International Journal of Fruit Science 12:294-303.
• Rowland, L.J., N. Alkharouf, N.V. Bassil, L. Beers, D.J. Bell, E.J. Buck, F.A. Drummond, C.E. Finn, J. Graham, J.F. Hancock, S. McCallum, and J.W. Olmstead. 2012. Generating genomic tools for blueberry improvement. International Journal of Fruit Science 12:276-287.
• Olmstead, J.W. 2012. New Blueberry Varieties Taking Flight. Florida Grower 105(10):4-5.
• Williamson, J. and J. Olmstead. 2012. Update on Different Blueberry Cultivars for Diversifying Crops. The Blueberry News 1(4):20-22.
• Williamson, J., J.W. Olmstead, and R.L. Darnell. 2012. Bright Idea for Bolstering Your Berry Crop. Florida Grower 105(10):6-7.
• Blaker, K., and J.W. Olmstead. 2012. Stone cell frequency and cell size variation of crisp and soft textured fruits from nine southern highbush blueberry cultivars. HortScience 47(9):S135. (Abstr.)
• Burkle, C., J.W. Olmstead, and P.F. Harmon. 2012. A potential vector of Blueberry necrotic ring blotch virus and symptoms on various host genotypes. Phytopathology 102:S4.17. (Abstr.)

Progress 10/01/10 to 09/30/11

Outputs
OUTPUTS: Seven southern highbush blueberry cultivars received patents: 'FL02-40' (USPP 21,719, Kestrel TM), 'FL96-43' (USPP 21,554, Flicker TM), 'FL01-173' (USPP 21,553, Meadowlark TM), 'FL03-291' (USPP 21,377, Bobolink TM), 'FL04-235' (USPP 21,376, Chickadee TM), 'FL05-107' (USPP 21,375, Vireo TM), and 'FL05-627' (USPP 21,374, Raven TM). Patented cultivars are available to any licensed propagator in Florida and under exclusive license in other areas of the United States and worldwide. Germplasm developed during the reporting period resulted from 202 different hybridizations utilizing Vaccinium corymbosum, V. darrowii, V. myrsinites, V. arboreum, V. stamineum and various interspecific hybrids between the species. Over 200 clonally propagated advanced selections identified during the 2010 season were planted during 2011 for evaluation, and 20 genotypes were identified for advancement into final-stage selection. From 2010 crosses, over 20,000 seedlings were planted for evaluation. Grower-cooperator trials were established in central and south-central Florida to evaluate advanced selections in very low chill environments. To better understand flavor development in southern highbush blueberry cultivars, five UF cultivars were tested at four developmental stages and four different harvest dates for total volatile aroma content. We continued to evaluate hybrids between V. corymbosum and V. arboreum plants for pollen fertility, vegetative, and reproductive characteristics, and fruit quality. Two backcross populations between these hybrids and cultivated southern highbush cultivars were evaluated for fruit quality. From crosses made between blueberry parents with a crisp, extremely firm fruit texture, individuals were evaluated for fruit texture phenotype to determine heritability of the trait. We continued collaboration with the USDA-ARS group in Winter Haven, FL to assess blueberry fruit texture by trained consumer panels. Seventy-five advanced selections that may be suitable for mechanical harvest of fresh blueberries were identified based on architecture, condensed ripening period, and fruit detachment force. A cross between a northern and southern highbush cultivar was evaluated for chilling requirement, vegetative and reproductive traits, and fruit quality in two locations (Georgia and Florida) to determine genetic loci contributing to the traits. Two research plots were evaluated for potential differences in vegetative and reproductive characteristics between cultivars propagated by tissue culture or softwood cuttings under Florida production conditions. Breeding program goals, methodology, and cultivar descriptions were disseminated through grower meetings and field days, update articles in the Florida Blueberry Growers Association quarterly newsletter, other trade publications, and published cultivar descriptions. Research program findings were disseminated to scientists through participation in scientific meetings and scientific publications. PARTICIPANTS: PROJECT: James Olmstead (Principal Investigator), Paul Lyrene (Emeritus Professor), David Norden (Research Coordinator), Werner Collante (Laboratory Manager). COLLABORATORS: Jeff Williamson (Univ. of FL, Extension Specialist), Steve Sargent (Univ. of FL, Postharvest Specialist), Rebecca Darnell (Univ. of FL), Anne Plotto (USDA-ARS), Elizabeth Baldwin (USDA-ARS), Jim Hancock (Michigan State Univ.), Lisa Rowland (USDA-ARS), Nahla Bassil (USDA-ARS), Chad Finn (USDA-ARS), Allan Brown (NC State Univ.), Alto Straughn (Straughn Farms), Ken Patterson (Island Grove Agricultural Products), Jerry Mixon (Mixon Family Farms), James Miller (Miller Blueberry Plantation). TRAINING AND PROFESSIONAL DEVELOPMENT: Kendra Blaker (PhD Student), Hilda-Patricia Rodriguez-Armenta (PhD Student), Gerardo Nunez (PhD Student), Jessica Gilbert (PhD Student), Silvia Marino (M.S. Student), Rachel Itle (Postdoctoral Associate). TARGET AUDIENCES: The primary target audience for this project are blueberry breeders, research and extension scientists working in Vaccinium production, and blueberry producers in the southeastern United States. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Blueberry cultivars that are adapted to warm areas such as Florida make it possible to harvest fresh blueberries from March 20 to May 20 in the northern hemisphere and from September 20 through November 20 in the southern hemisphere. Without low-chill cultivars such as those being bred in Florida, only frozen blueberries or blueberries long held in controlled atmosphere storage would be available during these four months. Recent cultivar releases from the UF blueberry breeding program have an impact by enabling greater production range by more consistent production in extremely low-chill areas ('FL96-43', 'FL02-40', and 'FL04-235'), and incorporation of traits such as upright growth, loose clusters, high yield, and early fruiting into a cultivar suitable for mechanized harvest for fresh market ('FL01-173'). Cultivars such as 'Farthing' and 'Sweetcrisp' have also performed well in machine harvest trials due to firm fruit texture. Research into the breeding value of interspecific hybrids has the potential to uncover valuable traits and phenotypes for inclusion in future cultivars. In particular, V. darrowii, and V. arboreum, native Florida blueberries, are an important source of adaptation for survival and productivity in Florida. Using a combination of flow cytometry, cytogenetics, and morphological characteristics, we have been able to better identify true hybrids between these interspecific crosses. Collectively, the products developed in the breeding program have continued to support expansion of worldwide blueberry production. In trained panel evaluation of blueberry fruit texture, average panel ratings followed closely with subjective breeder rankings for firmness, and panelists were able to clearly distinguish cultivars and selections ranked during breeding evaluations as crisp fruit. Each genotype evaluated by the trained panel was measured for fruit firmness and skin texture and correlations between flesh firmness, skin puncture force and sensory evaluations revealed the crisp texture to be only moderately correlated with firmer fruit. Research into flesh texture and its potential to be used for more consistent high-quality production of fresh fruit under mechanized harvest strategies will be critical for future growth of the Florida blueberry industry.

Publications

• Blaker, K., A. Plotto, E. Baldwin, and J.W. Olmstead. 2011. Correlation between sensory and instrumental measurements of crisp textured blueberries. HortScience 46(9):S283. (Abstr.)
• Du, X., A. Plotto, M. Song, J. Olmstead, and R. Rouseff. 2011. Volatile composition of four southern highbush blueberry cultivars and effect of growing location and harvest dates. Journal of Agricultural and Food Chemistry 59:8347-8357.
• Gilbert, J., T. Colquhoun, D. Clark, and J.W. Olmstead. 2011. Comparison of volatile profiles from frozen and refrigerated southern highbush blueberry fruit. HortScience 46(9):S381-382. (Abstr.)
• Itle, R.A., J.F. Hancock, C.E. Finn, E.J. Wheeler, J. Graham, S. McCallum, B. Branch, N.V. Bassil, L.J. Rowland, and J.W. Olmstead. 2011. Fruit development period in a blueberry (Vaccinium corymbosum L.) population segregating for chilling requirement. HortScience 46(9):S382. (Abstr.)
• Bassil, N.V., S. McCallum, J. Graham, J.W. Olmstead, R.A. Itle, A. Brown, E.J. Buck, C. Wiedow, C.E. Finn, J.F. Hancock, D. Main, N. Alkharouf, and L.J. Rowland. 2011. Progress toward a universal linkage map in tetraploid highbush blueberry. HortScience 46(9):S132-133. (Abstr.)
• Lyrene, P.M. 2011. First report of Vaccinium arboreum hybrids with cultivated highbush blueberry. HortScience 46:563-566.
• Lyrene, P.M. 2011. Successes in breeding blueberries for low-chill environments. HortScience 46(9):S51 (Abstr.)
• Marino, S., J. Williamson, and J.W. Olmstead. 2011. Field performance of southern highbush blueberry cultivars obtained from micropropagation and softwood cuttings at two Florida locations. HortScience 46(9):S113. (Abstr.)
• Olmstead, J. 2011. Banking on Berries With Bite. Florida Grower 104(10):32-33.
• Olmstead, J. and J. Williamson. 2011. Don't Hedge Your Bets. Florida Grower 104(10):28-29.
• Olmstead, J.W. 2011. Maintaining diversity in a recurrent selection breeding program for southern highbush blueberries. HortScience 46(9):S285. (Abstr.)
• Olmstead, J.W., J.G. Williamson, S.A. Sargent, A.D. Berry, and K.M. Blaker. 2010. Mechanical Harvesting Research for Fresh Packed Florida Blueberries. The Blueberry News Winter 2010.
• Rodriguez-Armenta, H.P., and J.W. Olmstead. 2011. Identification of tetraploid hybrids between Vaccinium arboreum and Vaccinium corymbosum by flow cytometry. HortScience 46(9):S284. (Abstr.)
• Williamson, J.G., J.W. Olmstead, S.A. Sargent, and A.D. Berry. 2011. Mechanical harvest potential of three southern highbush blueberry cultivars. HortScience 46(9):S283-284. (Abstr.)

Progress 10/01/09 to 09/30/10

Outputs
OUTPUTS: Patent applications were made for seven southern highbush blueberry selections: FL02-40 (12/587,283; 10/05/09), FL01-173 (12/587,285; 10/05/09), FL96-43 (12/587,298; 10/05/09), FL03-291 (12/584,568; 09/08/09), FL04-235 (12/584,556; 09/08/09), FL05-107 (12/584,553; 09/08/09), and FL05-627 (12/584,555; 09/08/09). Patented cultivars are available to any licensed propagator in Florida and under exclusive license in other areas of the United States and worldwide. Germplasm developed during the reporting period resulted from 204 different hybridizations utilizing Vaccinium corymbosum, V. darrowii, V. myrsinites, V. arboreum, and various interspecific hybrids between the species. Nearly 300 clonally propagated advanced selections identified during the 2009 season were planted during 2010 for evaluation, and 25 genotypes were identified for advancement into final-stage selection. From 2009 crosses, over 20,000 seedlings were planted for evaluation. More than 50 F1 hybrids between V. corymbosum and V. arboreum plants were evaluated for pollen fertility, vegetative, and reproductive characteristics, and fruit quality. Fifteen of the most vigorous and fertile were backcrossed to highbush cultivars to produce approximately 4,000 BC1 seedlings planted in 2010. A new planting was established at our research farm for evaluation of final stage selections and demonstration of UF cultivar releases. Current best management practices for Florida blueberry production were used, including pine-bark incorporated soil, in-row woven ground cover, drip irrigation, fertigation, and acid injection were included in the planting. Over 7,500 seedlings from crosses made between blueberry parents with a crisp, extremely firm fruit texture were planted to determine the inheritance of the crisp fruit texture phenotype. In addition, we collaborated with the USDA-ARS group in Winter Haven, FL to assess blueberry fruit texture by trained consumer panels. Evaluation of three cultivars for suitability for mechanized harvest of fresh fruit was made in 2010, with three machine-harvests of Sweetcrisp, Farthing, and FL01-173 (sold under the Trademark Meadowlark) compared to hand harvest at the same date. Two research plots were established to compare vegetative and reproductive characteristics between cultivars propagated by tissue culture or softwood cuttings under Florida production conditions. Breeding program goals, methodology, and cultivar descriptions were disseminated to producers through grower meetings and field days (Florida Blueberry Growers Association and Florida Organic Growers Association), update articles in the Florida Blueberry Growers Association quarterly newsletter, other trade publications, and published cultivar descriptions. Research program findings were disseminated to scientists through participation in scientific meetings (Plant and Animal Genome, North American Blueberry Research and Extension Workers Conference, and the American Society for Horticultural Science Conference)and scientific publications. PARTICIPANTS: PROJECT: James Olmstead (Principal Investigator), Paul Lyrene (Emeritus Professor), David Norden (Research Coordinator), Werner Collante (Laboratory Manager). COLLABORATORS: Jeff Williamson (Univ. of FL, Extension Specialist), Steve Sargent (Univ. of FL, Postharvest Specialist), Rebecca Darnell (Univ. of FL), Anne Plotto (USDA-ARS), Elizabeth Baldwin (USDA-ARS), Jim Hancock (Michigan State Univ.), Lisa Rowland (USDA-ARS), Nahla Bassil (USDA-ARS), Allan Brown (NC State Univ.), Alto Straughn (Straughn Farms), Ken Patterson (Island Grove Agricultural Products), Jerry Mixon (Mixon Family Farms), James Miller (Miller Blueberry Plantation). TRAINING AND PROFESSIONAL DEVELOPMENT: Kendra Blaker (PhD Student), Hilda-Patricia Rodriguez-Armenta (PhD Student), Gerardo Nunez (PhD Student), Silvia Marino (M.S. Student), Rachel Itle (Postdoctoral Associate), Ixchel Hernandez (Visiting scholar) TARGET AUDIENCES: The primary target audience for this project are blueberry breeders, research and extension scientists working in Vaccinium production, and blueberry producers in the southeastern United States. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Blueberry cultivars that are adapted to warm areas such as Florida make it possible to harvest fresh blueberries from March 20 to May 20 in the northern hemisphere and from September 20 through November 20 in the southern hemisphere. Without low-chill cultivars such as those being bred in Florida, only frozen blueberries or blueberries long held in controlled atmosphere storage would be available during these four months. Recent cultivar releases from the UF blueberry breeding program have an impact by enabling greater production range by more consistent production in extremely low-chill areas (FL96-43, FL02-40, and FL04-235), and incorporation of traits such as upright growth, loose clusters, high yield, and early fruiting into a cultivar suitable for mechanized harvest for fresh market (FL01-173). Research into the breeding value of interspecific hybrids has the potential to uncover valuable traits and phenotypes for inclusion in future cultivars. In particular, V. darrowii, and V. arboreum, native Florida blueberries, are an important source of adaptation for survival and productivity in Florida. Collectively, the products developed in the breeding program have continued to support expansion of worldwide blueberry production. In trained panel evaluation of blueberry fruit texture, average panel ratings followed closely with subjective breeder rankings for firmness, and panelists were able to clearly distinguish cultivars and selections ranked during breeding evaluations as crisp fruit. Each genotype evaluated by the trained panel was measured for fruit firmness and skin texture and correlations between flesh firmness, skin puncture force and sensory evaluations will be used to develop a rating scale to phenotype this trait. In mechanized harvest trials, packout for Sweetcrisp, Farthing, and FL01-173 averaged together was 94% marketable fruit for hand harvested plants versus 81% for mechanical harvest. This lower percentage was due primarily to a greater percentage of immature berries compared to hand-harvested fruit. The greater percentage of soft berries measured after mechanical harvesting was small by comparison to differences in immature fruit harvested. Changes in blueberry quality parameters measured during storage revealed that Sweetcrisp and Farthing had the best overall postharvest performance of the three cultivars mechanically harvested. These cultivars maintained the highest quality during 14 days of storage by better moisture retention that reduced the incidence of shrivel. Research into flesh texture and its potential to be used for more consistent high-quality production of fresh fruit under mechanized harvest strategies will be critical for future growth of the Florida blueberry industry.

Publications

• Lyrene, P. 2010. On the origin of Star. Florida Blueberry Growers Association The Blueberry News Summer 2010:2-3.
• Bassil, N., B. Gilmore, T. Mockler, J. Olmstead, A. Brown, and L.J. Rowland. 2010. SNP mining in blueberry using Illumina GAII sequencing. HortScience 45(8):S7-8. (Abstr.)
• Darnell, R.L., J.W. Olmstead, J.F. Williamson, P.M. Lyrene, S.A. Sargent, J. Spiers, W. Yang, and C. Seavert. 2010. A multi-disciplinary approach to sustainability and profitability of the U.S. blueberry production using the tree-like species V. arboreum. HortScience 45(8):S199. (Abstr.)
• Itle, R.A., E.A. Kabelka, and J.W. Olmstead. 2010. Construction of a RAPD and SSR-based linkage map in winter squash. HortScience 45(8):S186. (Abstr.)
• Lyrene, P. 2009. Blueberry varieties in Florida. Florida Blueberry Growers Association The Blueberry News Fall 2009:6-8.
• Rowland, L.J., N. Alkharouf, N.V. Bassil, L. Beers, D.J. Bell, E.J. Buck, F. A. Drummond, C.E. Finn, J. Graham, J.F. Hancock, S. McCallum, and J. Olmstead. 2010. Generating genomic tools for blueberry improvement - an update of our progress. HortScience 45(8):S197. (Abstr.)
• Sargent, S.A., A.D. Berry, J.G. Williamson, and J. Olmstead. 2010. Fruit detachment force of southern highbush blueberry: An aid to selection of cultivars suitable for mechanical harvest. HortScience 45(8):S306. (Abstr.)
• Williamson, J. and J. Olmstead. 2010. Blueberry Report: Counting on Cultivars. Florida Grower 103(10):6-8.
• Williamson, J. and S. Sargent. 2009. Can Florida blueberries be mechanically harvested Florida Blueberry Growers Association The Blueberry News Winter 2009:10-12.

Progress 10/01/08 to 09/30/09

Outputs
OUTPUTS: Seven southern highbush blueberry cultivars received plant patents: Scintilla (USPP 19,233), Farthing (USPP 19,341), FLX-1 (USPP 19,342), FLX-2 (USPP 19,381), Snowchaser (USPP 19,503), Sweetcrisp (USPP 20,027), and Primadonna (USPP 20,181). Seven additional selections were released for further trialing and potential commercialization. Patented cultivars are available to any licensed propagator in Florida and under exclusive license in other areas of the United States and worldwide. Several populations have been developed that segregate for a crispy flesh texture phenotype, potentially desirable for use in mechanized harvest. Numerous Vaccinium species have been used to study the breeding value of interspecific hybrids. Ten diploid Vaccinium darrowii selections collected from Florida stands were crossed with tetraploid V. corymbosum cultivars and advanced selections to identify additional V. darrowii clones that produce high percentages of unreduced gametes. Several tetraploid F1 seedlings were identified and backcrossed to assess fertility and potential for use in breeding. Fertility was variable, and further backcrossing will be necessary to develop cultivar-quality plant material. Thirty different hybrids between V. corymbosum and colchicine-induced tetraploid V. arboreum were used to cross with V. corymbosum cultivars. The vigor, fertility, and fruit quality of the F1 V. corymbosum x V. arboreum seedlings were highly variable. Three of the most vigorous of these clones were propagated for further use in breeding and to evaluate the introgression of desirable V. arboreum traits into the cultivated V. corymbosum germplasm. Breeding program goals, methodology, and cultivar descriptions are disseminated through grower meetings and field days, a quarterly newsletter, and published cultivar descriptions. PARTICIPANTS: Principal Investigator: James Olmstead (from July 1, 2009). Responsible for breeding program implementation, coordination of research projects, graduate and undergraduate student supervision. Emeritus Professor: Paul Lyrene (retired June 31, 2009). TARGET AUDIENCES: Blueberry breeders; scientists working on blueberries; consumers; fruit marketers; blueberry producers. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Blueberry cultivars that are adapted to warm areas such as Florida make it possible to harvest fresh blueberries from March 20 to May 20 in the northern hemisphere and from September 20 through November 20 in the southern hemisphere. Without low-chill cultivars such as those being bred in Florida, only frozen blueberries or blueberries long held in controlled atmosphere storage would be available during these four months. Recent cultivar releases from the UF blueberry breeding program have an impact on low-chill production through improvement over existing cultivars (Farthing), addition of novel traits such as crisp flesh texture (Sweetcrisp), expansion of the fruit maturity range to earlier dates (Snowchaser), expansion of the suitable growing area to locations other than Florida (FLX-1), and expansion into potential ornamental production markets (FLX-2). Research into the breeding value of interspecific hybrids has the potential to uncover valuable traits and phenotypes for inclusion in future cultivars. In particular, V. darrowii, and V. arboreum, native Florida blueberries, are an important source of adaptation for survival and productivity in Florida.

Publications

• Chavez, D.J., and Lyrene, P.M. 2009. Effects of self-pollination and cross-pollination of Vaccinium darrowii (Ericaceae) and other low-chill blueberries. HortScience 44: 1538-1541.
• Chavez, D.J., and Lyrene, P.M. 2009. Flowering and pollination studies with Vaccinium darrowii Camp and other Vaccinium species from Florida. Acta Hort. 810: 139-146.
• Chavez, D.J., and Lyrene, P.M. 2009. Interspecific crosses and backcrosses between diploid Vaccinium darrowii and tetraploid southern highbush blueberry. J. Amer. Soc. Hort. Sci. 134: 273-280.
• Chavez, D.J., and Lyrene, P.M. 2009. Production and identification of colchicines-derived tetraploid Vaccinium darrowii and its use in breeding. J. Amer. Soc. Hort. Sci. 134: 356-363.
• Chavez, D.J., and Lyrene, P.M. 2010. Hybridization of two diploid Vaccinium section Cyanococcus species with diploid Vaccinium arboreum in section Batodendron. Euphytica 171: 263-272.
• Haring, R.A., and Lyrene, P.M. 2009. Detection of colchicine induced tetraploids of Vaccinium arboreum with flow cytometry. Acta Hort. 810: 133-138.

Progress 10/01/07 to 09/30/08

Outputs
OUTPUTS: Ten V. darrowi (diploid) selections from the central Florida panhandle and 10 from the central Florida peninsula were crossed with 15 tetraploid cultivars or advanced selections from the Florida blueberry breeding program to produce tetraploid hybrids and to search for V. darrowi clones that produce numerous unreduced gametes. Three V. darrowi clones were found which, when crossed with tetraploid highbush cultivars, produced at least 100 hybrid seedlings per 1000 pollinated flowers. The direction of the cross (tetraploid x diploid or the reciprocal) was important. Although there was not an overall preferred direction for making the crosses, some V. darrowi clones produced many hybrids when used as females but not as males, and some were the reverse. Most of the inter-ploidy cross combinations produced few or no hybrids. Overall, several hundred hybrid seedlings were produced. Most are expected to be tetraploid. The V. darrowi clones used had highly-glaucous leaves, and this character was expressed by most of the hybrids. V. darrowi and V. arboreum (both diploid) could be crossed with relative ease if V. darrowi was female; the reciprocal cross produced some hybrids, but far fewer. Several hundred hybrids between colchicine-induced tetraploid V. arboreum and tetraploid highbush cultivars were extremely variable in vigor and morphology after 6 months in a field nursery. Some hybrids were extremely small. About 40 vigorous highbush cultivar x V. arboreum hybrids are expected to flower for the first time in spring 2009. These have vigor, stature, and growth habit similar to the parent species, but show clearly features of both species. Resistance to stem blight, incited by Botryosphaeria, is a principal goal of the cultivar development program, because disease pressure is high in Florida, the disease has the potential of killing entire fields, and alternative methods of control are not practical. Numerous low-chill tetraploid clones in advanced stages of testing have excellent vigor, good adaptation to Florida, high berry quality, and high, early yields. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Blueberry breeders; scientists working on blueberries; consumers; fruit marketers; blueberry producers. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Blueberry varieties that are adapted to warm areas such as Florida make it possible to harvest fresh blueberries from March 20 to May 20 in the northern hemisphere and from September 20 through November 20 in the southern hemisphere. Without low-chill varieties such as those being bred in Florida, only frozen blueberries or blueberries long held in CA storage would be available during these four months. Because the varieties that produce berries during these market windows are new, they are far from perfect. Much improvement in berry size, plant vigor and health, yield and berry quality have been seen in Florida blueberry varieties during the past 20 years, and further improvements are expected if work continues. Longer plant life, higher yields in warm production areas, and berries that maintain high quality and long post-harvest life when mechanically harvested will reduce the cost of production for growers and reduce prices and increase berry quality for consumers. Vaccinium darrowi, a Florida native blueberry, is an important source of adaptation to survial and productivity in hot, wet, environments. Because of the health benefits from berry consumption, and because blueberries can be very flavorful and easy to eat, they have the potential of moving from a minor to a major fruit crop if the proper varieties are developed.

Publications

• Lyrene, P.M. 2008. 'Emerald' Southern Highbush Blueberry. HortScience 43: 1606-1607.
• Lyrene, P.M. 2008. Breeding southern highbush blueberries. Plant Breeding Reviews. Vol. 30: 353-414.
• Lyrene, P.M. 2008. Blueberry. In: Register of new fruit and nut cultivars. List 44. C.E. Finn and J. R. Clark (editors). HortScience 43:1324.