Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/27/2001
Publication Date: N/A
Citation: Interpretive Summary: The soybean originated in China but has been grown in Korea and Japan for more than 2,000 years. These three countries are major sources of soybean germplasm for the United States. Very little is known about the relative levels of genetic diversity within these countries and genetic relationships of soybean germplasm among these countries. We can estimate the genetic relatedness among these soybean lines and the overall amount of genetic diversity by using DNA. DNA carries the genetic instructions for living organisms and the varieties with more similar DNA can be assumed to be more closely related and more variation in DNA can indicate greater levels of genetic diversity. Our results showed that the soybean germplasm within China contains much greater genetic diversity than the germplasm from either S. Korea or Japan. However, the germplasm from S. Korea and Japan is very distinct from that from China. The germplasm within China generally formed genetic groups based on the region of origin within the country but this was not true for the germplasm from S. Korea and Japan. This information will assist germplasm curators and plant breeders in efficiently managing and utilizing soybean germplasm for this part of Asia. These data confirm that China is the primary source of soybean germplasm and that germplasm from different parts of China are likely to be genetically distinct. S. Korea and Japan are secondary sources of germplasm that in general contain less genetic diversity but because this germplasm is genetically very different from Chinese germplasm it can also be valuable for soybean improvement.
Technical Abstract: This study was conducted to evaluate the genetic relationships among 120 soybean accessions from eight Chinese provinces, three Japanese regions, and three S. Korean provinces with RAPDs. The results indicate that the mean genetic distance within China is much larger than that within Japan or S. Korea, but smaller than that between China and Japan or S. Korea. Based on AMOVA results, 12% of the total variation is accounted for by countries, 11% by regional populations within countries, and 76% by individuals within populations. Cluster and principal component analyses almost completely separate the accessions from China from those of Japan and S. Korea, but could not separate the accessions from Japan and S. Korea. These results are consistent with the previous reports using enzymes and morphological data. The groups formed by cluster analysis were mainly based on the frequencies of RAPD fragments among accessions and generally reflected the geographical regions of origin. No clear connection was found between latitude and genetic diversity among these countries. Although the soybean accessions from Japan and S. Korea originally came from China, these data indicate that current accessions from Japan and S. Korea are genetically very distinct from those from China and similar to each other.