Small fruit production in the southern United States has been impacted greatly by fruit breeders this century. This workshop, co-sponsored by the American Pomological Society, includes presentations from individuals who have contributed collectively over 150 years to small fruit and grape breeding. James N. Moore has conducted breeding at the University of Arkansas, developing 30 cultivars. His presentation on brambles outlines achievements and future opportunities for improvement. Arlen Draper has been involved with the development of 61 small fruit cultivars while working with the USDA-ARS with an emphasis on blueberry. His presentation focuses on blueberry breeding and provides insights into the future of new blueberry cultivar developments. Gene Galletta has conducted small fruit breeding at North Carolina State University and USDA-ARS and has been involved with the development of 50 cultivars. His presentation reflects on the history of strawberry breeding in the South and the challenges that lie ahead. Ron Lane has served as a fruit breeder and horticulturist at the University of Georgia Experiment Station at Griffin and his work has emphasized the development of muscadine grape cultivars. The past and future of muscadine and bunch grape breeding is discussed in his paper. Articles from all authors in this workshop will be published in Fruit Varieties Journal in 1997.
John R. Clark and Curt R. Rom
Rajeev Arora and Lisa J. Rowland
and with high midwinter-hardiness did not always exhibit high DA resistance, which is perhaps related to other climatic and developmental factors. Others have also made similar observations; among blueberry cultivars ( Rowland et al., 2005 ), potato
Genetic variation in the architecture of berry crops will be reviewed. Examples will be given where changes in plant architecture have given increased yields, stabilized yields and improved fruit quality in strawberry, raspberry, highbush blueberry and currants.
Red raspberry will be emphasised as recent research on the architecture of the fruiting cane has enabled breeding strategies, based on plant architecture, to be developed.
Mark K. Ehlenfeldt, Allan W. Stretch, Nicholi Vorsa, and Arlen D. Draper
'Cara's Choice' is a mid-season ripening, tetraploid, hybrid blueberry (Vaccinium × 'Cara's Choice') that was developed by the cooperative breeding program of the Agricultural Research Service of the U.S. Department of Agriculture (USDA) and the New Jersey Agricultural Experiment Station (NJAES). 'Cara's Choice' was given its name in recognition of its excellent fruit quality with improved sweetness, firmness, and flavor.
Mark K. Ehlenfeldt, Allan W. Stretch, Nicholi Vorsa, and Arlen D. Draper
'Hannah's Choice' is an early-ripening, tetraploid, highbush blueberry (Vaccinium corymbosum L.) that was developed by the cooperative breeding program of the Agricultural Research Service of the U.S. Department of Agriculture (USDA) and the New Jersey Agricultural Experiment Station (NJAES). It was named because it represents an improvement in sweetness, firmness, and flavor over currently grown early cultivars.
M.K. Ehlenfeldt, A.D. Draper, and J.R. Clark
In the 1970s, the U.S. Department of Agriculture (USDA) began developing low-chill-adapted highbush blueberry (Vacchizium corymbosum L.) for the southern United States (lat. 29° to 32°N) by using germplasm of the native southern species, V. darrowi Camp. This breeding work resulted in the release of several low-chill southern highbush blueberry (SHB) cultivars in the mid-1980s. These cultivars have been evaluated for yield and adaptation at several locations through the southern regional blueberry germplasm evaluation trials. These trials have shown that organic mulch is required for good performance of SHB. The one-fourth V. darrowi composition of SHB cultivars presents problems of freeze damage at some locations. This problem may be resolved by breeding cultivars through several alternative approaches.
Donald J. Merhaut and Rebecca L. Darnell
Commercial blueberry production is limited primarily to soils where ammonium, rather than nitrate, is the predominant N form. However, Vaccinium arboreum, a species native to northern Florida, often is found growing in soils where nitrate is the major N form. This species may serve as a breeding source or rootstock for commercial blueberries, expanding the potential soil types that may be used for blueberry cultivation. In our study, in vivo nitrate reductase activity (NRA) was measured in roots and leaves of 2-year-old seedlings of V. arboreum and a commercial cultivar, V. corymbosum `Sharpblue'. Plants were grown hydroponically in sand culture and fertilized with a modified Hoagland's solution containing N as either ammonium, ammonium nitrate, or nitrate. Vaccinium arboreum averaged nitrite at 200, 60, and 20 nmol/g fresh weight per h for nitrate, ammonium nitrate, and ammonium fertilized plants, respectively. `Sharpblue' root NRA was significantly lower, averaging nitrite 50, 38, and 8 nmol/g fresh weight per h for nitrate, ammonium nitrate, and ammonium fertilized plants, respectively. NRA was much lower in leaves than roots of V. arboreum, averaging nitrite at ≈15 nmol nmol/g fresh weight per h across N treatments. No NRA was detected in the leaves of `Sharpblue', regardless of N treatment. These data suggest that V. arboreum may be used as a rootstock or breeding source to expand blueberry production into soil types that are higher in nitrate than the soils typically used for blueberry production.
Mark K. Ehlenfeldt
Inbreeding coefficients were calculated for highbush blueberry (Vaccinium corymbosum L.) cultivars based on a tetrasomic inheritance model. This model yielded lower inbreeding coefficients than previous calculations based on a disomic tetraploid inheritance model. Recent trends in breeding have resulted in significant use of V. darrowi Camp as a source of low-chilling germplasm for use in the southern United States. There is also a trend toward increased inbreeding in several crosses from which recently released cultivars have been derived. Increased inbreeding coefficients do not represent a detrimental situation in blueberry per se.
Mark K. Ehlenfeldt and Robert B. Martin Jr.
Eighty-seven highbush blueberry and species-introgressed blueberry cultivars were evaluated for fruit firmness in the 1998-2000 growing seasons with a FirmTech 1 automated firmness tester. Significant differences were observed among cultivars. An average firmness of 136.1 g·mm-1 of deflection (g·mm-1 dfl) was observed across all studied cultivars, and a range of 80.4 g·mm-1 dfl (`Herbert') to 189.0 g·mm-1 dfl (`Pearl River'). Species ancestry was not consistently related to firmness; however, cultivars with higher firmness values often possessed a higher percentage of Vaccinium darrowi Camp and V. ashei Reade ancestry. Conversely, cultivars with softer than average fruit often possessed a higher percentage of lowbush (V. angustifolium Ait.) ancestry. This information may help to identify sources of breeding material for increased firmness in highbush blueberry hybrids.
Duane W. Greene
occurring, the extent of production, and the primary blueberry species responsible for this production. Chapter 2 first reviewed the taxonomy of the blueberry. Breeding efforts past and present were discussed next, followed by a description of