Center of genetic diversity and dissemination pathways in mung bean deduced from seed protein electrophoresis

Seed protein of 581 local strains of mung bean, Vigna radiata (L.) Wilczek, collected from throughout Asia, were analyzed by SDS-polyacrylamide gel electrophoresis. Eight protein types were recognized based on the combination of four albumin bands and three globulin bands. The frequency of each protein type strain showed a clear geographical cline. The pattern of geographical distribution of the protein types reflected the regions of genetic diversity, and two dissemination pathways in mung bean were proposed. The region of genetic diversity in seed protein was western Asia (Afghanistan-Iran-Iraq area). Mung bean may have spread mainly to the east by two routes from India, where the domestication of mung bean is believed to have occurred. One route led to Southeast Asia; strains consisting of a few protein types with prominent protein type 1 were disseminated from India to the Southeast Asian countreis. Thus, the strain composition in Southeast Asia was very simple, with the strains being similar to one another. Another dissemination pathway may have been the route known as the Silk Road. Since protein type 7 and 8 strains could not be found throughout Southeast Asia, it is assumed that these strains spread from western Asia or India to China and Taiwan via the Silk Road, and not by the route from Southeast Asia.