基于ISAP标记分析西南扁穗牛鞭草无性系种质遗传多样性和亲缘关系

Genetic Diversity and Relationship of Hemarthria Compressa Clones from Southwest China Revealed by ISAP Markers

利用ISAP标记对来自中国西南地区的44份扁穗牛鞭草（Hemarthria compressa）无性系材料的遗传多样性和群体遗传变异进行了分析研究.结果表明：从72对引物中筛选出19对扩增条带清晰、稳定性好的引物,共扩增出432条带,其中有316条带具有多态性,多态性条带比例（PPB）达73.15％,多态性信息量（PIC）在0.161～0.312之间,平均值为0.269,Shannon多样性指数（H）平均值为0.399,标记指数（MI）平均值为4.584,分辨率（RP）平均值为9.419,基因型指数（GI）平均值为0.937.各无性系间的遗传相似性系数（GS）在0.464～0.908之间,平均值为0.614.UPGMA聚类分析与基于模型的STRUCTURE分析结果相似,显示供试材料间的遗传关系与其地理来源无明显的相关性,采用AMOVA分析对2种方法划分的类群发现大部分变异来自于群体内部.表明ISAP标记能有效地用于扁穗牛鞭草遗传多样性以及基因型鉴定,同时为扁穗牛鞭草无性系的保存、鉴定和新品种选育提供理论依据.

Intron sequence amplified polymorphism （ISAP） was applied to assess the genetic diversities of 44 whipgrass （Hemarthria compressa） clones from southwest China. The 19 primer pairs of producing highly reproducible ISAP bands were screened from 72 primer pairs. The 432 discernible DNA fragments with 316 （73.15%） polymorphic bands were generated using the 19 primer pairs. The values of polymorphism information contents （PIC） varied from 0. 161 to 0. 312 with an average of 0. 269. The various genetic variation indices were computed, such as Shannon diversity index （0. 399）, Marker Index （4. 584）, Resolving Power （9. 419） and Genotype Index （0. 937）. Genetic similarity coefficients （GS） among the ISAP data of 44 whipgrass clones ranged from 0. 464 to 0. 908 with a mean of 0. 614. The patterns observed in a dendrogram constructed with the UPGMA cluster analysis based on GS were confirmed by Bayesian model-based STRUCTURE analysis, revealing no direct association between genetic divergence and geographical origins. High levels of genetic variation within groups were found by the analysis of molecular variance （AMOVA）. Overall, the study demonstrated that ISAP marker was a feasible and effective technique for whipgrass germplasm management, identification and the more efficient choice in breed- ing programs.