四川育成小麦品种的SSR遗传多态性及系谱关系(英文)

SSR Genetic Diversity among Modern Advanced Wheat Cultivars(Triticum aestivum L.) in Sichuan and its Relationships with Their Pedigree

选用小麦染色体上的60 SSR标记，对来自四川3个不同单位近30年育成的47个普通小麦品种的遗传多样性进行了分析。60个SSR位点中共检测到118个等位变异，每个位点的等位变异范围为1～5个，平均为1．08个。品种的遗传相似系数从1980年以来有逐渐升高的趋势。育成小麦品种的3个染色体组以B染色体组遗传多样性最高，D染色体组最低。通过UPGMA聚类，可以把47个品种分为3个松散的群，在每一个群内，很多品种都来自于同一个育种单位，与系谱来源一致。这些结果表明由于不同育种单位采用相似遗传特性的育种亲本，四川育成小麦品种的遗传基础越来越狭窄，种质资源的创新和遗传多样性拓宽是今后小麦育种和小麦生产成效的前提。比较而言，推广面积大的品种相互之间遗传多样性较大，归于不同的类群，具有更广泛的适应性。

Simple sequence repeats （SSRs） or microsatellites, with high polymorphism and abundant information, were used to detect the genetic diversity of wheat （Triticum aestivum L. ） getrnplasm. In this study, 47 wheat advanced eultivars （lines） released by three different breeding stations in Siehusn 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 frona 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 Siehusn 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 an urgent need to diversify the genetic base by using new sources from the germplasm in wheat improvement programs in Sichuan province.