[Comparative analysis of genetic diversity revealed by genomic-sSR, EST-SSR and pedigree in wheat (Triticum asetivum L.)]

Abstract

Two SSR molecular markers, genomic-SSR and EST (expressed sequence tagged)-SSR, were used to measure the genetic diversity among 18 accessions of common wheat with known pedigrees, which were collected from winter wheat production region in Northern China. In addtion, the genetic diversity revealed by pedigree, EST-SSR and genomic-SSR was also compared. The results showed that the average number of alleles per genomic-SSR locus is 3.34, which is higher than that of EST-SSR (2.31), indicating that genomic-SSR is more polymorphic than EST-SSR. Genomic-SSR and EST-SSR were used to calculate the genetic distance (GD) in different materials. The mean GD value of EST-SSR for the 18 wheat genotypes is 0.3996,which is lower than that of genomic-SSR (0.5458). At the locus level, the mean GD calculated using pedigree information is higher (0. 9716) than that of genomic-SSR and EST-SSR markers (0.5458 and 0.3996). Therefore, although polymorphism of EST-SSR is low as compared to genomic SSR,it provides a more accurate evaluation of genetic relationship, especially when accessions are very closely related in pedigree. The strategy for improving the genetic diversity of wheat was also discussed.