Title: The USDA-ARS National Plant Germplasm System Malus collection: diversity of cultivars and wild species Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: September 17, 2012
Publication Date: October 1, 2012
Citation: Volk, G.M., Richards, C.M., Gross, B.L., Fazio, G., Chao, C.T. 2012. The USDA-ARS National Plant Germplasm System Malus collection: diversity of cultivars and wild species (abstract). 6th Rosaceous Genomics Conference (RGC6), September 30 - October 4, 2012, Trento, Italy. p.131. Technical Abstract: The USDA-ARS National Plant Germplasm System (NPGS) Plant Genetic Resources Unit (PGRU) apple collection in Geneva, NY conserves over 2500 trees as grafted clones. We have compared the genotypes of 1131 diploid Malus × domestica Borkh. cultivars to a total of 1910 wild and domesticated samples representing 41 taxonomic designations in the NPGS collection to identify those that are genetically identical based on nine simple sequence repeat (SSR) loci. A total of 238 M. × domestica and 10 samples of other taxonomic groups shared a genotype with at least one other M. × domestica individual. We identified examples of genotypes for cultivars that matched genotypes of known rootstocks, and indicated that these accessions may not accurately represent the indicated named clones. Twenty three sport families, comprised of 104 individuals, were identified that could not be differentiated using the nine SSR loci. SSR markers as well as phenotypic traits were used to compare the di versity of the currently designated core collection to that of the entire diploid grafted collection. We have identified a set of individuals that augment the diversity of the existing core collection, thus capturing more than 95% of the allelic and phenotypic diversity. We have also identified sets of 100 individuals that also capture the desired diversity within the collection. Five of the selected markers (CH01h01, CH02d08, CH01f02, G12, GD147) overlap with sets of markers that have been used to fingerprint European apple collections, thus making it possible to compare and coordinate collection inventories on a world-wide scale.