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Research Project: Management of Temperate-Adapted Fruit, Nut, and Specialty Crop Genetic Resources and Associated Information

Location: National Clonal Germplasm Repository

Title: Comparative diversity analysis of southeastern Rubus germplasm through molecular and pedigree techniques

Author
item Bradish, Christine - North Carolina State University
item Overbaugh, E. - North Carolina State University
item Ballington, J. - North Carolina State University
item Fernandez, Gina - North Carolina State University
item Bassil, Nahla

Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/26/2016
Publication Date: 11/26/2016
Citation: Bradish, C.M., Overbaugh, E., Ballington, J., Fernandez, G.E., Bassil, N.V. 2016. Comparative diversity analysis of southeastern Rubus germplasm through molecular and pedigree techniques. Acta Horticulturae. 1127:157-162. doi: 10.17660/ActaHortic.2016.1127.25.

Interpretive Summary: The North Carolina bramble collection contains hundreds of diverse blackberry, raspberry, and black raspberry selections, and crosses among them were made to expand commercial production in the Southeast. For over 50 years, the breeding program has used wild plants from various parts of the world to bring in novel and desired traits. Despite this, diversity is narrow, especially for black raspberries and blackberries. DNA-based molecular fingerprinting can be used to assess genetic relatedness and ancestry among selections or cultivars, and assist in designing crosses, making selections, and verifying trueness to type. We fingerprinted 91 individuals of red raspberry, black raspberry, and blackberry cultivars. Unique molecular profiles were obtained for 61 samples. These fingerprinted plants maintained at other institutions as well as in house duplicates can now be tested for trueness-to-type. Understanding diversity among and within Southeastern bramble germplasm is critical for the development of molecular breeding technologies, and paves the way for speeding up release of new cultivars with the targeted traits.

Technical Abstract: The North Carolina Rubus germplasm collection contains hundreds of diverse blackberry, raspberry, and black raspberry (Rubus L.)selections, among which intra- and interspecific crosses were made to achieve breeding goals for expanding commercial production in the Southeast. For over 50 years, the breeding program has used wild species from various parts of the world to introgress novel and desired traits. Despite this, it is known that diversity within cultivated Rubus is narrow, especially for black raspberries and blackberries, which are mostly selfing or apomictic. Molecular fingerprinting can establish the relatedness in a population and assist in designing crosses, making selections, verifying lineage and trueness to type testing. Within the North Carolina State University Rubus Breeding Program, molecular profiling and diversity analyses of 91 red raspberry (R. idaeus L.), black raspberry (R. occidentalis L.), and blackberry (Rubus subg. Rubus) cultivars was conducted using six simple sequence repeat (SSR) markers. Unique molecular profiles using all alleles were successfully determined for 61 germplasm samples. STRUCTURE software was used to infer population relationships amongst individuals, with seven distinct germplasm groups clustering based on similarity of allele fragment size. These fingerprinted accessions maintained at other institutions as well as in house duplicates can now be tested for trueness-to-type based on the six loci profiles. Understanding diversity among and within Southeastern Rubus germplasm is critical for the development of molecular breeding technologies, and paves the way for improved cultivar development techniques.