Genetic diversity of chinese cultivated soybean revealed by SSR markers

China is the center of origin of soybean [Glycine mar (L.) Merr.] and is therefore expected to represent a primary source of germplasm for this crop. Genetic diversity assessments among Chinese soybean accessions should provide useful information for local and international soybean researchers to more effectively utilize this material. A sample of 129 accessions were selected to represent phenotypic variability for 14 agronomic and morphological traits in the Chinese soybean collection. These accessions were analyzed with 60 mapped simple sequence repeats (SSRs) to determine the genetic diversity represented. In total, 732 alleles were detected (12.2 alleles per locus) and the polymorphic information content (PIC) among accessions varied from 0.5 to 0.92 with a mean of 0.78. Pairwise coefficients of genetic distance among all accessions ranged from 0.05 to 0.91 (mean 0.23). Unweighted pair-group method arithmetic average (UPGMA) analysis showed that the accessions formed five major clusters; two contained primarily Northern ecotypes, one contained primarily Yellow River Valley ecotypes, and one contained Southern ecotypes. The fifth cluster contained a mixture of Northern and Yellow River Valley ecotypes. Accessions from the lower regions of the Yellow River Valley possessed the greatest allelic richness, had the lowest pairwise genetic diversity estimates, and were dispersed throughout the five clusters, suggesting that the Yellow River Valley may be center of diversity for Chinese cultivated soybean. The results indicated that stratified sampling based on seven primary ecotypes may represent an optimal strategy for assembling a representative core collection of Chinese soybean.