小豆遗传差异、群体结构和连锁不平衡水平的SSR分析

Genetic Diversity, Population Structure and Linkage Disequilibrium in Adzuki Bean by Using SSR Markers

利用57对小豆SSR标记和31对绿豆SSR标记,用5份日本材料作对照,对249份中国小豆种质进行遗传差异、群体结构和连锁不平衡(LD)分析。结果表明,共检测到630个等位变异,SSR位点等位变异数在2～17之间,遗传多样性指数范围为0.024～0.898,平均为0.574。15个不同地理来源群体间表现出显著的遗传多样性差异,其中中国云南最高,河北和天津最低。聚类分析将254份材料划分为3个类群,在一定程度上和地理生态环境相关。LD分析显示和其他作物相比,小豆LD衰减距离较短,最大衰减距离为5.8 cM(R2>0.1),基因组LD平均衰减距离小于1 cM(R2>0.1,P<0.001)。

A total of 249 Chinese adzuki bean accessions were analyzed with 57 adzuki bean SSR markers and 31 mungbean SSR markers to ascertain genetic diversity, population structure and linkage disequilibrium （LD） with five Japanese materials as the contrast. The results indicated that 630 alleles were detected with 2-17 alleles per locus and a mean genetic diversity index of 0.574, ranging from 0.024 to 0.898. There were significant differences among 15 populations of adzuki bean resources in genetic diversity from diversed geographic origins, with the highest in Yunnan and the lowest in Hebei and Tianjin. The 254 adzuki bean accessions could be divided into three subgroups based on STRUCTURE and NJ cluster. The population structure derived from them was positively correlated to some extent with the geographic eco-type. LD analysis revealed that there was a shorter LD decay distance in adzuki bean than that in other crops. The maximum LD decay distance, estimated by curvilinear regression, was 5.8 cM （R2〉0.1）, with a whole genome LD decay distance less thanl cM （R2〉0.1, P〈0.001）. The results of this study should pro- vide valuable information for future association mapping using this Chinese adzuki bean collection.