关键词: 小麦, 遗传多样性, SSR, 聚类分析, 系谱

Abstract: Simple sequence repeats (SSRs) or microsatellites, with high polymorphism and abundant information, were used to detect the genetic diversity of wheat (Triticum aestivum L.) germplasm.In this study, 47 wheat advanced cultivars (lines) released by three different breeding stations in Sichuan province, were analyzed with 60 SSRs.A total of 108 allelic variants were detected at 60 SSR loci, ranging from one to five per locus with an average of 1.08.Genetic similarities (GS) ranged from 0.42 to 0.97 with average of 0.68.The average GS value of cultivars bred in different periods showed that the genetic diversity had the decreasing tendency since 1980s.The comparison of A, B, D chromosomes based on SSR markers indicated that the polymorphism of genome B was the highest and that of genome D was the lowest.UPGMA analysis in total genome based on GS value produced three loose groups.Most of the cultivars developed from the same breeding stations clustered in one group.Moreover, the parentage of advanced cultivars also contributed significantly to the clustering pattern.It was clearly shown that most current advanced cultivars in Sichuan China possessed narrow genetic background due to sharing breeding materials of other breeding stations or using certain elite breeding parents by different breeding stations.Thus it is anurgent need to diversify the genetic base by using new sources from the germplasm in wheat improvement programs in Sichuan province.

Key words: Wheat, genetic diversity, SSR, cluster analysis, pedigree