Molecular Diversity Among G. Hirsutum Accessions in the Gossypium Diversity Reference Set

A core set of SSR markers were employed to develop accession profiles and analyze genetic relationships among 2,254 plant introductions of cotton (Gossypium spp.) including wild species, landraces, and adapted cultivars from around the world as represented in the US National Cotton Germplasm Collection.  This group of plant introductions (accessions) is collectively known as the Gossypium Diversity Reference Set (GDRS).  1,540 G. hirsutum accessions are included in the GDRS.  These accessions were roughly equally divided between cultivar-types and landrace-types.  Molecular analyses are being conducted to explore genetic relationships between these two groups as well as within the landraces to see how landrace groups previously determined by morphology or geography match with those clusters as determined by molecular methods.  We will also further analyze this molecular information for the identification of species-specific alleles, documentation of introgression, and identification of misclassified or duplicated accessions. Altogether, these analyses will provide a more comprehensive knowledge of molecular diversity that is necessary to facilitate the most effective utilization and the greatest efficiency in maintenance of the US National Cotton Germplasm Collection.