以SRAP和EST-SSR标记分析芝麻种质资源的遗传多样性

利用SRAP和EST-SSR分子标记对192份国内外芝麻种质资源进行遗传多样性分析。结果表明，2种标记都能很好地揭示品种间遗传关系；在31对SRAP引物组合扩增的270个等位基因中多态性占62.08%，平均每对引物可以检测5.45个；25对SSR引物扩增的136个等位基因中56.28%呈多态性，平均每对检测引物产生3.04个。UPGMA聚类结果显示，在相似性系数为0.70时，192份材料可被分为3个类群；阈值为0.75时类群Ⅰ又可分为6组，表明芝麻品种遗传多样性比较丰富。我国南部地区芝麻品种遗传多样性(多样性指数H_i=2.572)较中部(H_i=2.117)和北部地区 (H_i=2.114)丰富。分析结果将有助于更好地保护和利用芝麻种质资源，并为育种工作提供依据。

Genetic Diversity Analysis of Sesamum indicum L. Germplasms Using SRAP and EST-SSR Markers

Sesame (Sesamum indicum L.), an important oil-yielding plant, is one of the most ancient crops in tropical and subtropical areas. Despite its nutritional value and importance, the research on sesame has been scarce. In this study genetic relationships among 134 Chinese sesames, 41 alien sesames, and 17 improved cultivars were analysed using SRAP and EST-SSR markers. Large genetic variability was found within all the germplasm collection. A total of 270 SRAP markers were recorded using 31 primer combinations, each primer detected 5.45 loci; While 25 pairs of SSR amplified 136 loci, each primer detected 3.04 loci. Mantel test revealed that the relation of genetic similarity matrix between SRAP and SSR was significant (r=0.7864, t=5.2571, P<0.01) for 192 species, so the UPGMA dendrogram was set up based on the integrated data of SRAP and SSR. The 192 accessions were grouped into three robust clusters, and cluster Ⅰ consisted of six groups, which was not revealed any association between genotype and geographical origin. Accessions came from one region were distributed throughout the dendrogram. The results revealed by the genetic distance and Shannor-weaver index of sesame germplasm resources from different regions that the genetic diversity of sesame was high, and in our nation the southern was higher than the others. We presumed that the sesame species was introduced to the Southern China firstly, of course it needs other evidence to be substantiated. The cluster result suggests that there was a considerable gene flow among different regions. So when we choose the parents in sesame breeding focusing on the genetic relationships is a good strategy.