Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/10/2005
Publication Date: 8/30/2005
Citation: Chen, Y., Nelson, R.L. 2005. Relationship between origin and genetic diversity in chinese soybean germplasm. Crop Science. 45:1645-1651. Interpretive Summary: The soybean originated in China and much of the germplasm in the USDA Soybean Germplasm Collection originally came from China. Finding ways of economically and meaningfully classifying these primitive varieties according to genetic relationships would be very helpful in efficiently utilizing this critical genetic diversity. By estimating genetic relationships among primitive soybean varieties from four provinces in China with DNA markers, we found that the origin of primitive varieties was often a good estimate of the genetic relationships among these varieties. This information indicates that prior to scientific agriculture of the past century there was little movement of primitive varieties so varieties within a region were more closely related to each other than were varieties among regions. This information will be useful to scientists interested in preserving and utilizing soybean genetic diversity.
Technical Abstract: As the center of domestication of the soybean [Glycine max (L.) Merr.], China has an abundance of soybean germplasm. Information about the amount and distribution of genetic diversity in Chinese germplasm is critical to effective germplasm management. The objectives of this research are to estimate the genetic variation within and among four geographically diverse provinces (Zhejiang, Sichuan, Gansu and Hebei) in China and to determine the relationship between geographical origin and genetic diversity by means of selected primitive cultivars and RAPD markers. Ten accessions from each province were characterized using RAPD fragments produced by 31 selected decamer primers. CNS, an important U.S. ancestral line, was also included. Genetic variation was estimated by AMOVA analysis with 241 random amplified polymorphic DNA (RAPD) fragments. Genetic distances were calculated using Jaccard's coefficients and expressed as Euclidean distances. Two hierarchical methods, unweighted paired group method using arithmetic averages (UPGMA) and Ward's minimum-variance method; a non-hierarchical procedure, VARCLUS; and multidimensional scaling (MDS) were applied to define the genetic relationships. Significant genetic differences were found among all provinces except between Zhejiang and Sichuan. The greatest variation was observed between Hebei and Zhejiang. There was disagreement among the clustering methods but each procedure identified clusters of accessions that originated from the same province. Based on all of the information, six major clusters containing 32 accessions were defined with each cluster dominated by accessions from a single province. The remaining nine accessions from Gansu, Sichuan and Zhejiang were placed in a single cluster by VARCLUS but were not grouped consistently by the two hierarchical methods. These data provide additional evidence that primitive cultivars of China were generally genetically isolated in relatively small geographical areas.