RAPD marker diversity among cultivated and wild soybean accessions from four Chinese provinces

Wild soybean (Glycine soja Siebold & Zucc.) is the ancestor of cultivated soybean [Glycine max (L.) Merr.] and is widely distributed in China, Japan, Korea, Taiwan, and eastern Russia. In North America, modern soybean cultivars are derived from a very limited germplasm base. Use of more soybean introductions and G. soja lines in breeding programs to expand the genetic base of and incorporate specific traits into commercial soybean cultivars could be beneficial. This study was conducted to evaluate the genetic variation between and within annual Glycine species and to determine geographical patterns of variation within and between the annual Glycine species. Forty G. max and 40 G. soja accessions from four Chinese provinces, Heilongjiang, Shandong, Jiangsu, and Shanxi, were surveyed with random amplified polymorphic DNA (RAPDs). The results indicated that the genetic distance (GD) within the G. soja group was larger than that within the G. max group, but smaller than that between the G. max and G. soja groups. Twenty-three more polymorphic RAPD fragments were detected within the G. soja group than within the G. max group. Nine fragments were present only in G. soja lines. On the basis of AMOVA analysis, 18% of the total variation could be accounted for by species, 15% by populations within species, and 67% by individuals within populations. Cluster and principal component analyses completely separated the G. max and G. soja groups. The groups formed by cluster analyses generally reflected the geographical regions of origin. Glycine max and G. soja lines for the same province were not more genetically related than were accessions of different species from different provinces, but the GDs between the G. soja lines from Heilongjiang and the G. max accessions from all other provinces were less than for the G. soja accessions from any other provinces. The results of this study could be used for exploiting the genetic diversity in the two species in breeding programs and in sampling and managing germplasm collections.