Submitted to: American Society of Plant Biologists
Publication Type: Abstract Only
Publication Acceptance Date: 7/24/2012
Publication Date: N/A
Technical Abstract: The genetic diversity and population structure present in the Ethiopia sorghum collection maintained by the USDA-ARS, National Plant Germplasm System (USDA-ARS-NPGS) is unknown. In addition, passport information is absent for 83% of these accessions which limit its evaluation and utility. Therefore, 137 Ethiopia accessions were randomly selected and characterized with 20 SSR markers. These markers resulted in the identification of 289 alleles with an average polymorphic information content of 0.78, and a high number of rare alleles (frequency below 0.05). Estimates of expected and observed heterozygosity were 0.78 and 0.23, respectively, which are higher than in previous diversity studies. Population structure analysis identified two subpopulations of 77 and 41 accessions, while a third group was comprised of 19 accessions whose classification was not defined (i.e. hybrids). Analysis of molecular variances determined variation within subpopulations as the major source of variation. Likewise, genetic differentiation between subpopulations was moderate (Fst = 0.10). These results indicated a continuous exchange of genes between subpopulations exist in Ethiopia. This extensive recombination history positions this germplasm as an important resource for the study and dissection of agricultural traits by association mapping. Effective population size of the sample was estimated at 134, therefore, a larger sample size is required to study the genetic variability of the entire collection. The Ethiopian collection is a highly, genetically diverse germplasm, and the genetic information presented herein is valuable to ex-situ and in-situ conservation programs seeking to preserve this germplasm for research and improvement programs.