Analysis of the Genetic Variability for the Mini-core Collection of Chinese Wild Soybean(Glycine soja) Collection in the National Gene Bank based on SSR Markers

A set of mini-core collection of 96 wild soybean accessions were evaluated for the extent of genetic diversity in Chinese Wild Soybean Collection using 70 pairs of SSR markers.The results showed that 1278 alleles were detected in total with an average of 18.3 alleles per locus.Polymorphism information index(PIC) and number of unique alleles(NUA) indicated that Northeast China had the highest values of PIC and NUA,followed by the Yangtze river valley,and the South had the lowest values of PIC and NUA at the geographical regional level.Nevertheless at the individual germplasm level in the geographical regions,the southern region was characterized by the highest values of the PIC and NUA,and the genetic diversity seemed to be decreased from the southern to northeastern regions in wild soybean.Cluster analysis showed that there was obvious genetic differentiation between the typical and semi-wild soybeans in the Chinese Wild Soybean Collection and the individual accessions had weak clustering of geographical regions.The higher heterozygosity of the semi-wild soybeans supported the hypothesis that semi-wild soybean originates from natural cross between wild and cultivated soybeans.Our present results also suggested that the genes of cultivated soybeans could have introgressed into wild soybean species;some individual accessions or families with 100-seed weights of less than 3.0g might originate from the event of natural cross between wild and cultivated soybeans.