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Nicholi Vorsa and Richard Novy

Vaccinium darrowi (D) is a wild blueberry species with low chilling requirements for budbreak, and heat and drought tolerance. Breeding efforts to incorporate these desirable traits into cultivated blueberry (V. corymbosum) (C) would be facilitated with a better understanding of the genomic homology between the two species. An interspecific tetraploid hybrid (CCDD, 2n=4x=48) was used to evaluate genome homology and interspecific recombination. Pollen mother cells examined at diakinesis and early metaphase I exhibited an average of 4.6 chain bivalents, 11.4 ring bivalents, 1.0 chain quadrivalent, and 3.0 ring quadrivalents. This data most closely fits a chromosome pairing model in which there is a greater pairing affinity between homologues than homoeologues. An analysis of the inheritance of 14 RAPD markers unique to V. darrowi in 72 backcross progeny of the V. darrowi–corymbosum hybrid also supported the pairing model: Seven of the 14 markers deviated significantly from tetrasomic inheritance ratios, expected if chromosome pairing was totally random. On the basis of the cytogenetic and RAPD analyses, the genomes of V. darrowi and V. corymbosum are divergent from one another, with preferential pairing within genomes. This outcome suggests there may be difficulty in breaking undesirable linkages when introgressing desirable traits from V. darrowi to V. corymbosum.

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Ann Marie Connor, James J. Luby, and Cindy B.S. Tong

Narrow-sense heritability and among-family and within-family variance components were estimated for antioxidant activity (AA), total phenolic content (TPH), and anthocyanin content (ACY) in blueberry (Vaccinium L. sp.) fruit. AA, TPH, and ACY were determined in the parents and in 10 offspring from each of 20 random crosses for each of 2 years at Becker, Minn. Offspring-midparent regression analysis provided combined-year heritability estimates of 0.43 ± 0.09 (P ≤ 0.0001) for AA, 0.46 ± 0.11 (P ≤ 0.0001) for TPH, and 0.56 ± 0.10 (P ≤ 0.0001) for ACY. Analyses of variance delineated variation among and within families for AA, TPH, and ACY (P ≤ 0.001). Year-to-year variation in the means for all offspring genotypes was not significant for AA or TPH, but there were changes in rank between years for families and for offspring within families for these traits. Year-to-year variation in the mean for all offspring genotypes was significant for ACY, but rank changes were observed only among offspring within families, not among families. In total, 18 of 200 offspring from 7 of the 20 crosses were transgressive segregants for AA, exceeding the higher parent of the cross by at least two sds. Estimates of variance components showed that variation among families accounted for 24% to 27% of total variance for the three traits. However, variation within families was greater than that among families, accounting for 38% to 56% of total variance for the three traits. These results suggest that increasing antioxidant activity in blueberry through breeding is feasible, and that the breeding strategies utilized should exploit the large within-family variation that exists.

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D. Scott NeSmith and Mark K. Ehlenfeldt

In addition to breeding cultivars for commercial blueberry ( Vaccinium sp.) production, ornamental value has been a trait of interest for many blueberry breeders for a number of years ( Galletta and Ballington, 1996 ). An older dwarf cultivar

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Yifei Wang, Stephanie K. Fong, Ajay P. Singh, Nicholi Vorsa, and Jennifer Johnson-Cicalese

flavonoid and organic acid profiles of diploid blueberry species compared with cultivated tetraploids also suggests their potential value in blueberry breeding for phytochemical improvement. For instance, V. pallidum , V. tenellum, and V. boreale clones

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Steven A. Sargent, Adrian D. Berry, Jeffrey G. Williamson, and James W. Olmstead

fresh packed blueberries will be received by buyers with acceptable quality. NeSmith et al. (2002) reported that MH rabbiteye blueberry lost 20% to 30% firmness as compared with HH fruit. The University of Florida’s breeding program has produced

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Rebecca L. Darnell, Bruno Casamali, and Jeffrey G. Williamson

1160 Lyrene, P.M. 1997 Value of various taxa in breeding tetraploid blueberries in Florida Euphytica 94 15 22 Merhaut, D.J. 1993 Effects of nitrogen form on vegetative growth, and carbon/nitrogen assimilation, metabolism, and partitioning in blueberry

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Stephen J. Stringer, Arlen D. Draper, Donna A. Marshall, and James M. Spiers

Southern highbush blueberries ( Vaccinium sp.) are hybrids derived from crosses between the (northern) highbush blueberry ( V. corymbosum ) and germplasm developed from Vaccinium spp. that is both native and adapted to the southeastern United

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Chad E. Finn, Bernadine C. Strik, Theodore A. Mackey, Patrick A. Jones, Nahla V. Bassil, and Robert R. Martin

-ARS) breeding program in Corvallis, OR, and was released in cooperation with Oregon State University’s Agricultural Experiment Station. ‘Echo’ is the second strongly repeat fruiting (remontant, off-season, perpetual flowering) blueberry developed from a northern

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Mark K. Ehlenfeldt

‘Razz’ is a midseason-ripening, tetraploid, highbush blueberry ( Vaccinium corymbosum L.) with unique raspberry flavor overtones that has been released by the cooperative breeding program of the Agricultural Research Service of the U.S. Department

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Blair J. Sampson, Stephen J. Stringer, and Donna A. Marshall

is linked to greater pollination efficiency, higher fruit sets, and larger berries ( Sampson and Cane, 2000 ). Perhaps the efficiencies of honeybees and other manageable bee species can be improved by selectively breeding blueberry cultivars with