Jin, yan , Lu, Baorong , He, Tianhua .
A sampling strategy for assessing genetic diversity of wild soybean populations using ISSR markers.
Wild soybean (Glycine soja Sieb. et Zucc) is commonly considered to be the ancestor of cultivated soybean (Glycine max (Linn.) Merr.), and it serves as an important gene pool for soybean breeding. Wild soybean is a self-compatible annual that occurs in semi-disturbed habitats in parts of Korea, Japan, Russia, and China, which is a center of diversification for soybean taxon. The deterioration of its habitat has led to severe population declines in China and elsewhere. It is urgent to the conserve genetic diversity of this species, and although ex situ collections exist, few studies have been done on natural wild soybean populations to obtain basic information for effective conservation. To investigate sampling strategies for assessing the genetic diversity of wild soybean populations in eastern China, we collected 67-100 samples from mapped individuals in each of four natural populations in Shanghai, Heibei and Liaoning Province. Results from ISSR markers indicated that relatively high genetic variation (He = 0.17 to 0.26) exists in these wild soybean populations. Kinship coefficients and auto-spatial correlation revealed local genetic structure within populations. There was a positive spatial correlation of individuals within short distances (10-23 m) and random distribution across longer distances. To account for patches of related individuals within populations, we suggest sampling individuals at ~25 m intervals across the entire population to maximize the genetic variation sampled. Regression analysis showed that the relationship between genetic diversity and the number of samples used was similar in all of the four populations. We found that about 30-40 individuals was the optimum sample size for characterizing population genetic diversity based on ISSR markers. This type of sampling strategy can be used to 1) identify the best populations for in situ conservation of genetic diversity in soybean, and 2) guide further sampling of seeds for ex situ germplasm collections.
1 - Insititute of Biodiveristy Science, Fudan University, 220 Handan Road, Shanghai, 200433, China
2 - Curtin University of Technology, Department of Environmental Biology, P.O. Box U1987, Perth, Western Australia, 6845, Australia
3 - Ohio State University, Depatment of Evolution, Ecology and Organismal Biology, 318 W. 12th Ave., Columbus, Ohio, 43210-4321, United States
Presentation Type: Paper
Location: Peruvian (Cliff Lodge)
Date: Wednesday, August 4th, 2004
Time: 8:00 AM