基于SSR标记的河南省狗牙根遗传多样性及群体遗传结构分析

A SSR marker analysis of genetic diversity and population genetic structure of bermudagrass in Henan Province

应用SSR分子标记,对河南省15个居群共288份狗牙根材料进行遗传多样性及群体遗传结构分析,结果表明,10对引物共扩增出173条条带,其中163条为多态性条带,多态性条带百分率为94.29%,表明河南省狗牙根具有丰富的多态性。15个居群间的遗传分化系数为0.3857,即发生在居群间的遗传变异达到38.57%,大部分的遗传变异发生在居群内部,居群间基因流为0.7964,居群之间存在一定程度的基因交流。不同居群间遗传一致度的变化范围是0.746~0.964,平均为0.767。15个居群间的UPGMA聚类分析结果表明居群间没有完全按照地理来源进行聚类,遗传距离和地理距离矩阵之间的Mantel检验结果表明狗牙根居群间的遗传距离与地理距离之间无相关性。288份狗牙根材料之间的遗传距离为0.0173~0.5205,平均为0.3113,UPGMA聚类结果将所有材料分为3组。基于Structure软件的群体遗传结构分析结果表明,可将288份狗牙根材料分为2个亚群和一个混合型群体,与288份材料的UPGMA聚类结果基本一致,由此可判断两个亚群的遗传背景单一,混合型群体存在一定的种质基因渗透,遗传背景较为复杂。

In this study,SSR molecular markers were used to analyze the genetic diversity and population genetic structure of bermudagrass(Cynodon dactylon)in Henan Province.A total of 173 bands were amplified by 10 pairs of primers,of which 163 bands(94.29%)were polymorphic,indicating that the polymorphism of tested accessions is rich.The coefficient of genetic differentiation among the 15 populations was 0.3857,meaning that 38.57% of the genetic variation occurred between populations and the majority of the genetic variation occurred within populations.The gene flow among populations was 0.7964,and there was a degree of gene communication among populations.The genetic identity among different populations ranged from 0.746 to 0.964,with an average of 0.767.A UPGMA cluster analysis among the 15 populations showed that the populations were not clustered completely according to geographical origin.A Mantel test between genetic distance and geographical distance matrix showed that there was no correlation between genetic distance and geographical distance among populations.The genetic distance between 288 bermudagrass accessions ranged from 0.0173 to 0.5205,with an average of 0.3113.According to the UPGMA cluster analysis results,the 15 studied bermudagrass populations fell into three groups.Meanwhile,structure analysis suggested that the 288 bermudagrass accessions could be grouped into two subpopulations and one mixed population,which was basically consistent with the grouping results based on UPGMA clustering.This indicated that the two subpopulations had a single genetic background,while the mixed population had additional germplasm gene penetration,and the genetic background was complex.