Submitted to: Botanical Bulletin of Academia Sinica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/14/2005
Publication Date: N/A
Citation: N/A Interpretive Summary: Genetic diversity of crop species refers to the type of variation, amount of variation, and distribution of variation among and within certain defined geographic areas. Objective 1 was to compare randomly selected Chinese soybean varieties with pre-selected Chinese varieties (based upon morphology and protein traits), using DNA methods. There was no statistically significant difference between random and pre-selection of soybean varieties even though the mean number that measured diversity was numerically higher in the pre-selected varieties. Objective 2 was to estimate the genetic diversity within and among the six Chinese provinces, and to compare this value to 64 USA modern varieties. The Chinese varieties maintained a significantly higher level of DNA variation than the USA varieties. Soybean breeders can use this information to select Chinese soybean varieties to use as parents to improve U.S. varieties.
Technical Abstract: To evaluate the levels of genetic diversity in USDA soybean germplasm from central China, 107 accessions were examined at 46 RFLP loci. We compared genetic diversity in 43 randomly selected accessions with that for 53 pre-selected accessions based upon root tip fluorescence, pubescence morphology, and isozyme patterns at ten enzyme systems. We also evaluated levels of genetic diversity of the central Chinese accessions (n = 107) by comparing previously studied ancestors and milestone cultivars (n = 64) in the USA. Finally, we estimated the degree of genetic differentiation among six Chinese provinces (Anhui, Gansu, Henan, Jiangsu, Shaanxi, and Shanxi). There was no significant difference between pre-selected and random accessions for genetic diversity (He = 0.393 for pre-selection and He = 0.394 for random selection), though the former (mean number of alleles per locus, A = 2.44) harbors more alleles than the latter (A = 2.13). This is attributed to the fact that many of alleles found in pre-selected accessions were present at very low frequencies (mean effective number of alleles, Ae = 1.72). In spite of very similar levels of RFLP genetic diversity (He) between the two groups, a broader range of alleles detected in the pre-selected accessions suggest that pre-selection of accessions based on isozyme data may be useful for selecting germplasm collections with a greater number of RFLP alleles. The central Chinese accessions maintained a significantly higher level of RFLP genetic diversity than the NAC (He = 0.405, A = 2.50 for central China vs. He = 0.339, A = 2.08 for the USA). We detected a significant genetic differentiation among the six provinces (mean GST = 0.133). These results suggest that Chinese germplasm collections from various regions or provinces could be used to enhance genetic diversity of USDA soybean germplasm.