Working group session:
Germplasm and Genetic Stocks
Presentation type:
oral
Authors:
Hinze, Lori; Percy, Richard; Yu, John; Frelichowski, James; Fang, David; Gore, Michael; Scheffler, Brian
Presenter:
Hinze, Lori
Correspondent:
Percy, Richard
Abstract:
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 Cotton Germplasm Collection. Eight diploid genomes representing 28 species and 272 accessions along with one tetraploid genome representing six species and 1,982 accessions were genotyped with a set of 104 SSR markers. These SSRs are evenly distributed throughout the genome with two markers per chromosome arm. Due to bulking of ten individuals and amplification of duplicated homeologous loci, SSRs could not be reliably scored as co-dominant markers. Instead, the results were scored as a dominant (AFLP-type) marker system. A total of 1,702 polymerase chain reaction fragments (bands) were scored and all were found to be polymorphic across this set of accessions. The tetraploid accessions had more polymorphic bands (79.8%) than the diploid accessions (13.6%). The overall PIC value was 0.077 and ranged from 0.003 in the F diploid genome represented by G. longicalyx to 0.073 in the AD tetraploid genome represented by six species. Molecular characterization efforts continue with multivariate analysis of genetic relationships between individual accessions, species, and genomes. This molecular information will be further analyzed and used in the identification of species-specific alleles, documentation of introgression, creation of core subsets, 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 Cotton Germplasm Collection.