江苏裸大麦种质资源遗传多样性和群体结构分析

Genetic diversity and population structure analysis of naked barley germplasm resources in Jiangsu province

长江中下游及沿海地区曾是我国裸大麦的两大产区之一,其中以江苏省面积最大,是全国裸大麦重要生产基地。研究江苏裸大麦种质资源的遗传多样性和群体结构,对于拓宽现有裸大麦资源的遗传基础、挖掘丰富优异等位变异、提高裸大麦育种效率具有重要意义。本研究利用38对SSR标记对230份江苏裸大麦材料和其他7个来源的109份裸大麦材料进行了遗传多样性分析,共检测到242个等位变异,平均每对引物检测到的等位基因数和有效等位基因数分别为6.3684个和3.0932个,平均Shannon’s多样性指数和Nei’s基因多样性指数分别为1.2189和0.5857。多态性信息含量均值为0.5486,具有高度多态性。按照来源划分群体,江苏裸大麦群体观测到的等位基因数最多为5.4737个,有效等位基因数为2.5347个,平均Shannon’s多样性指数、Nei’s多样性指数和多态性信息含量(PIC)值为0.9551、0.5004和0.4593。群体间和群体内的遗传变异是导致裸大麦间产生遗传多样性的主要原因,裸大麦群体间发生遗传分化的主要原因是基因流。不同群体间的遗传分化系数和遗传距离与地理位置的远近没有明确相关性。聚类分析、群体结构分析和主成分分析将裸大麦资源均分为4组,聚类结果可相互佐证且与地理位置相关性不明显。群体结构分析表明,江苏裸大麦群体在4个类群均有分布,与其他群体分化明显。339份材料中295份材料Q值≥0.6,大部分裸大麦材料血缘比较单一。

The middle and lower regions of the Yangtze River and the coastal areas were one of the two major production areas of naked barley in China,especially Jiangsu province,which was the largest planting area and was an important production base of naked barley.Studying the genetic diversity and population structure of Jiangsu naked barley germplasm resources is of great significance for broadening the genetic base of existing naked barley resources,mining excellent alleles,and improving the breeding efficiency of naked barley.In this study,a set of 38 simple sequence repeat(SSR)markers were used to assess the ge-netic diversity of 230 naked barley materials from Jiangsu and 109 materials from seven other sources.242 alleles were detected with an average allele number of 6.3684 and the effective allele number of 3.092 for each SSR.The mean values of Shan-non-Weaver index and Nei were 1.2189 and 0.5857,respectively.The average PIC value was 0.5486,indicating the high poly-morphism of the SSRs.When the materials were divided into eight groups according to the regions,the largest number of alleles observed in Jiangsu population was 5.4737 and the mean values of effective alleles,Shannon’s diversity index,Nei’s diversity index,and PIC were 2.5347,0.9551,0.5004,and 0.4593,respectively.The genetic diversity of naked barley materials was mainly caused by genetic variation between and within populations,and gene flow was the main reason for the genetic differentiation among the naked barley materials of different groups.The genetic differentiation coefficient and genetic distance between various groups were not significantly correlated with the geographical location between groups.Based on clustering analysis,population structure analysis,and principal component analysis,the naked barley resources were divided into four groups,and the clustering results could corroborate each other and have not clear correlation with geographical location.The population structure analysis showed that the Jiangsu materials were distributed in all four groups and were clearly differentiated from other groups.In 339 materials,the Q-value of 295 materials were higher than 0.6,and most of them had relatively single genetic background.