|Dossett, Michael - Agri Food - Canada|
|Mockler, Todd - Danforth Plant Science Center|
|Filichkin, Sergei - Oregon State University|
|Fernandez, Gina - North Carolina State University|
|Perkins-veazie, Penelope - North Carolina State University|
|Weber, Courtney - Cornell University - New York|
|Agunga, Robert - Ohio University|
|Rhodes, Emily - Ohio University|
|Scheerens, Joseph - Ohio University|
|Yang, Wei - Ohio University|
|Graham, Julie - Scottish Crops Research Institute (SCRI)|
|Fernandez Fernandez, Felicidad - East Malling Research|
|Yun, Song Joong - Chonbuk National University|
Submitted to: Acta Horticulturae
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2012
Publication Date: 8/1/2014
Citation: Bassil, N.V., Dossett, M., Hummer, K.E., Mockler, T., Filichkin, S., Peterson, M.E., Lee, J., Fernandez, G., Perkins-Veazie, P., Weber, C., Agunga, R., Rhodes, E., Scheerens, J.C., Yang, W., Lewers, K.S., Graham, J., Fernandez Fernandez, F., Yun, S., Finn, C.E. 2014. Genetic and developing genomic resources in black raspberry. Acta Horticulturae. Available: http://www.actahort.org/books/1048/1048_/.htm.
Interpretive Summary: A survey was conducted of genetic markers in 137 wild genotypes and 21 cultivars of black raspberry. The objective was to compare genetic diversity between the two groups, to better understand patterns of diversity in the germplasm, and to assist in determining the best ways of utilizing this germplasm in breeding for crop improvement. Overall, genetic diversity was much lower in black raspberry cultivars than in wild genotypes and black raspberry cultivars were found to be closely related. In addition, discrepancies in the fingerprints of some black raspberry cultivars and their reported parents were found. Six black raspberry cultivars were found to have identical genetic fingerprints and could not be uniquely identified indicating that they may have been mislabelled at some point in the past or that the genetic markers available may not be good enough to differentiate between them. In contrast to cultivated black raspberry, wild black raspberry genotypes were very diverse and individuals were highly inbred. Differentiation between wild black raspberry genotypes is strong and it appears that wild populations may be inbred from either strong population founder effects and/or isolation. For the most part, differentiation between wild black raspberry populations does not appear to show strong geographical trends and there is some evidence that diversity in wild black raspberry has not been exhaustively sampled. Several wild populations clustered with cultivated black raspberry, however, most of these were found to have larger-than average fruit or other morphological traits indicating that they may be escaped seedlings from cultivated plants. This work has shown that wild black raspberry genotypes may be a valuable resource for broadening the genetic base of black raspberry breeding populations and may contribute to long-term breeding progress in this crop.
Technical Abstract: Breeding progress in black raspberry (Rubus occidentalis L.) has been limited by a lack of genetic diversity in elite germplasm. Black raspberry cultivars have been noted for showing very few phenotypic differences and seedlings from crosses between cultivars for a lack of segregation for important traits. Despite these challenges, little molecular work has been done to explore genetic diversity and relationships in wild and cultivated black raspberry germplasm. Microsatellite, or simple sequence repeat (SSR), markers are highly polymorphic codominant markers useful for studying genetic diversity, population genetics, genetic fingerprinting and other applications. Using 21 polymorphic SSR markers, we examined genetic diversity in 148 wild and cultivated black raspberry accessions. Black raspberry cultivars clustered tightly and showed higher than expected heterozygosity while heterozygosity of wild accessions was low. Relationships between wild black raspberry accessions were poorly resolved and regional clusters were mostly absent from our analysis. Our results indicate that wild black raspberry germplasm is a relatively untapped resource available for future breeding.