To determine if any of the available techniques for estimating stability in different environments are useful in blueberry (Vaccinium ashei Reade and V. corymbosum L.), 14 clones were evaluated in nine environments for ripening date and yield. Type 1 and 2 stability statistics, plots for each genotype mean versus its coefficient of variation (cv) across environments (genotype grouping), environmental index regression, and cluster analyses were compared. The highest yielding rabbiteye and southern highbush clones across locations were not deemed stable by Type 1 and Type 2 stability statistics, genotype grouping, or environmental regression technique. No evidence of curvilinear response was found. The nonparametric cluster analysis with known cultivars included appears to be most useful compared to other methods of estimating stability used in this study.
Creighton Gupton, John Clark, David Creech, Arlie Powell, and Susan Rooks
Chad E. Finn and James J. Luby
Progenies from a partial diallel mating scheme using 17 highbush (Vaccinium corymbosum L.), lowbush (V. angustifolium Ait.), and half-high (V. corymbosum/V. angustfolium hybrid) parents were subjectively evaluated for fruit color, picking scar, and firmness in two seasons. General combining ability (GCA) mean squares were significant (P ≤ 0.01 for all traits), but specific combining ability was significant for no traits (P > 0.05). However, the correlation coefficients between the GCA effects and the parental phenotype scores were low, indicating that selection of parents within this material based on their phenotype may not be indicative of progeny performance. GCA effects depended to some extent on the species ancestry. Vaccinium angustifolium parents produced progeny with relatively dark, soft fruit with large scars. Lowbush parents having light-blue fruit produced segregating progenies that were heavily skewed toward dark fruit, regardless of the color or species ancestry of the other parent. When the highbush and half-high parents were crossed with one another, segregation patterns were typical of predominately additive gene action.
Gad G. Yousef, Mary A. Lila, Ivette Guzman, James R. Ballington, and Allan F. Brown
private breeding programs (e.g., yield and adaptation). Field experimental trials and sample preparation. Blueberry plants were established and maintained through North Carolina State University’s (NCSU) blueberry breeding program. Two-year-old seedlings
Douglas A. Phillips, Philip F. Harmon, James W. Olmstead, Natalia A. Peres, and Patricio R. Munoz
used as a parent in the University of Florida blueberry breeding program in the past, raising concerns regarding potential susceptibility of offspring from these crosses. In addition, there is a concern about whether other commercial cultivars may be
Lisa Klima Johnson, Anish Malladi, and D. Scott NeSmith
). Large fruit size is an important trait for selection during the development of new varieties in blueberry breeding programs ( NeSmith, 2009 ). Although considerable variation in fruit size is observed among rabbiteye blueberry genotypes, the basis of
J.R. Ballington, C.M. Mainland, S.D. Duke, A.D. Draper, and G.J. Galletta
1 Professor. 2 Blueberry Breeding Researcher. 3 Research Geneticist, retired. 4 Research Geneticist. Paper no. 12206 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, NC 276967643. We express appreciation to
J.R. Ballington', C.M. Mainland, S.D. Rooks, A.D. Draper, and G.J. Galletta
1 Professor. 2 Blueberry Breeding Researcher. 3 Research Geneticist, retired. 4 Research Geneticist. Paper no. 12386 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, NC 27695 7602. We express our
Peter Boches, Nahla V. Bassil, and Lisa Rowland
Sixty-nine accessions representing wild and domesticated highbush blueberry (Vaccinium corymbosum L.) germplasm were genotyped using 28 simple sequence repeats (SSRs). A total of 627 alleles was detected and unique fingerprints were generated for all accessions. Suspected duplicate accessions of `Coville' and `Ivanhoe' had DNA fingerprints that were identical to `Coville' and `Ivanhoe', respectively. Genetic similarity measures placed wild and cultivated blueberries in separate groups. Northern highbush blueberries grouped among ancestral clones that were used extensively in blueberry breeding such as `Rubel' and `Stanley'. Southern highbush blueberries formed a separate group from northern highbush blueberries. The microsatellite markers used here show excellent promise for further use in germplasm identification, in genetic studies of wild Vaccinium L. populations, and for constructing linkage maps.
M.K. Ehlenfeldt, A.W. Stretch, and A.D. Drape
A group of 1031 genotypes representing 245 different crosses from a joint U.S. Dept. of Agriculture-New Jersey Agricultural Experiment Station blueberry breeding program was evaluated for blueberry red ringspot virus (BBRRSV) symptoms after 8 years of field exposure. Among 41 parents represented by 10 or more progeny, significant differences were observed in offspring BBRRSV expression. The species Vaccinium lamarckii Camp. (4x) and V. amoenum Ait. (6x) and the cultivars Woodard (6x) and Earliblue (4x) seem to have high frequencies of alleles for BBRRSV resistance. Significant differences were also found among 21 different crosses. The most resistant cross was `Elizabeth' x `Earliblue', which had a 23% BBRRSV incidence. Progeny evaluation revealed that none of the parents involved produced families in which all plants were resistant; hence, resistance to this virus may be under polygenic control.
John R. Clark and Curt R. Rom
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.