利用微卫星标记分析山西糜子的遗传多样性

Genetic Diversity Analysis of Broomcorn Millet(Panicum miliaceum L.) of Shanxi Province Using Microsatellite Markers

山西是中国糜子主产区之一,有丰富的地方品种和农家种种质资源。利用微卫星标记分析糜子资源的遗传多样性,明确其遗传背景,便于加强糜子各品种之间的基因交流以及优异种质的筛选和利用,同时对种质资源的亲缘关系分析提供科学依据。利用27对SSR引物分析57份山西糜子的遗传差异,采用PowerMarker 3.25计算每对引物的多态性信息含量,采用PopGen1.32计算每对引物和两个生态区的观测等位基因等遗传参数。用MEGA5.0构建Neighbour-Joining聚类图,利用Structure 2.3.4鉴定遗传类群,采用Ntsys2.11进行主成分分析。结果显示27对SSR引物共检测出71个等位变异,平均每个位点扩增出2.6296个等位基因,各引物对的有效等位变异占观测等位变异的76.94%。各引物对的基因多样性指数为0.4140～1.0446,平均为0.7686;PIC为0.0601～0.7158,平均为0.5667。两生态区的观测杂合度等遗传参数相差不大。基于N-J遗传距离将57份材料分为3个类群,类群Ⅰ属于黄土高原春夏糜子区,类群Ⅱ、类群Ⅲ均属均于北方春糜子区和黄土高原春夏糜子区。遗传结构分析将57份糜子材料分为3个类群,绿色类群的基因多样性指数和PIC比蓝色、红色类群高。两种聚类结果基本一致,分布方式均与地理位置相关。主成分分析结果将晋北部材料与晋中、晋南部材料相区别,说明两生态区糜子的遗传背景因地理气候因素有明显差异,与遗传结构群体分析结果一致。研究表明,山西省糜子资源的遗传多样性丰富。

Shanxi province of China acts as one of the main producing areas of common millets and also a center of local varieties and farmer germplasm resources.Exploration of genetic diversity in common millet germplasms will provide a scientific basis for studying the origin and evolution of common millet,which would strengthen gene transfer between varieties of common millet and facilitate the utilization of excellent resources.In this study,we analyzed the genetic differences among 57 common millet accessions from Shanxi province by 27 pairs of SSR polymorphic primers.The statistical analysis were conducted by software PowerMarker 3.25,PopGen 1.32,MEGA 5.0,Structure 2.3.4 and Ntsys 2.11.Within this accessions,71 alleles were detected with an average of 2.6296 alleles at each locus.The number of effective allele account for 76.94% of the observed one.The Shannon index of all primers ranged from 0.4140 to 1.0446,with an average of 0.7686,The range of PIC was 0.0601-0.7158,with an average of 0.5667.The values of genetic diversity indexes such as the observed heterozygosity have no much difference between two ecotopes.Basing on Neighbor-joined genetic distance,57 materials were divided into 3 groups,the group Ⅰ belongs to the Loess Plateau spring & summer-sowing ecotopes,the group Ⅱ belongs to the Loess Plateau spring & summersowing and Northeast spring-sowing,the same as the group Ⅲ.The analysis of genetic structure divided 57 common millet accessions into three groups.In terms of the values of Shannon’s information index and PIC,the green group is higher than that of the others.The results of two cluster analysis are consistent and they showed a close correlation between geographical region and the method of clustering.Meanwhile the materials in northern of Shanxi province were distinguished from the middle and the southern of Shanxi province by the means of PCA,The result indicated that the genetic background of two ecotopes has obvious differences due to geographical and climatic factors,which is consistent with the result of genetic structure analysis between populations.Thus,the genetic diversity of common millet resources in Shanxi province was abundant.