普通小麦Genomic-SSR和EST-SSR分子标记遗传差异及其与系谱遗传距离的比较研究

采用Genomic-SSR和EST—SSR标记技术，对来自我国北方冬麦区的18份普通小麦品种(系)的遗传多样性进行了探讨，并与系谱遗传距离进行了比较分析。研究发现，平均每个Genomic—SSR检测到的等位基因数为3．34个，明显高于EST-SSR的2．31个。遗传距离(GD)计算结果显示，18个小麦基因型之间的EST—SSR平均遗传距离较小，仅为0．3996，低于Genomic—SSR的GD平均值0．5458。尽管EST-SSR揭示出的多态性明显低于Genomic-SSR，但系谱分析和聚类结果均表明，与Genomic—SSR相比，EST—SSR标记能更准确地反映出不同小麦基因型之间的遗传和亲缘关系。据此可以认为，EST—SSR是评价小麦遗传多样性的一种理想标记形式。研究还证实，一个骨干亲本与由其衍生出来的品种(系)之间的遗传差异一般较小，并对拓宽普通小麦遗传基础的策略和方法进行了讨论。

Comparative Analysis of Genetic Diversity Revealed by Genomic-SSR,EST-SSR and Pedigreein Wheat (Triticum asetivum L.)

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.