Abstract: Sequence-related amplified polymorphism(SRAP) molecular markers were used to detect the genetic diversity of Themeda caudata(Nees) A.Camus collected from Minjiang River,Qingyijiang River and Tuojiang River of Sichuan province in China.Twenty primer pairs produced 158 polymorphic bands,averaging 4.9 bands per primer pair.The average percentage of polymorphic bands was 62.03%.Nei’s genetic similarity coefficient(GS) of tested accessions ranged from 0.6899 to 0.9430,and the average Nei’s coefficient was 0.8755.Results suggested that there was rich genetic diversity among the wild resource of tested T.caudata.The 29 accessions can be clustered into two dendrogram groups at the GS=0.78.The second dendrogram group can be clustered into two subgroups at the GS=0.81 and the second subgroup can be clustered into three subclasses at the GS =0.83.Moreover,the accessions from the same origin frequently clustered into one group.Genetic differentiation between and within five eco-geographical groups of T.caudata was estimated by Shannon’s diversity index,which showed that 50.77% genetic variance existed within group,and 49.23% genetic variance was among groups.Based on Nei’s unbiased measures of genetic identity,UPGMA cluster analysis indicated that there was a correlation between genetic differentiation and eco-geographical habits among the groups.

Key words: Themeda caudata(Nees) A.Camus, SRAP, Genetic diversity, Cluster analysis

摘要： 采用SRAP方法分析,对采自中国四川岷江、青衣江和沱江流域的29份野生苞子草(Themeda caudata(Nees) A.Camus)材料进行遗传多样性分析。结果表明:用20对SRAP引物组合共得到158条可统计条带,其中多态性条带98条,平均每对引物扩增出4.9条多态带,多态性条带比率为62.03%。材料间的遗传相似系数GS值变化范围为0.6899～0.9430,平均GS值为0.8755,这些结果表明供试野生苞子草具有丰富的遗传多样性;对所有材料进行聚类分析,在GS值为0.78的水平上,可聚成2大类;在GS值为0.81的水平上,第2大类Ⅱ可聚为2亚类;在GS值为0.83的水平上,第2亚类Ⅱ又可聚为3子类,大部分来自相同或相似生态地理环境的材料聚为一类;基于Shannon多样性指数估计6个苞子草生态地理类群内和类群间的遗传分化,发现类群内的遗传变异占总变异的50.77%,而类群间的遗传变异占总变异的49.23%;对各生态地理类群基于Nei氏无偏估计的遗传一致度聚类分析说明,各生态地理类群间的遗传分化与其所处的生态地理环境具有一定的相关性。

关键词: 苞子草, SRAP, 遗传多样性, 聚类分析