基于SSR标记的朝天椒种质遗传多样性分析

Analysis of Genetic Diversity in Germplasm of Capsicum frutescens Based on SSR Markers

探究以贵州为主的西南地区朝天椒种质遗传多样性,为朝天椒种质的保续、利用与分子标记辅助选择提供准确参考依据。利用20个SSR(简单串联重复序列)分子标记,对112份西南地区朝天椒种质资源进行遗传多样性分析。结果表明,20对SSR引物共检测出65个等位变异,每对引物的等位变异为2~4个,平均每对引物3.25个等位变异,平均有效等位基因数为1.8294,平均多态性信息量(PIC)为0.5440,平均Shannon’s信息指数(I)为0.7234,观测杂合度(Ho)、期望杂合度(He)、Nei’s期望杂合度的平均值分别为0.4920、0.4337、0.4318,所筛选出的20对SSR引物多态性较高,能较好地反映朝天椒不同地方种间的遗传多样性信息。聚类结果表明,供试材料居群间遗传相似系数(GS)值为0.5692~0.9538,平均值为0.7733,朝天椒种质间的遗传相似性相对较高,材料间的亲缘关系比较接近。在GS值0.7670处将供试材料分为4类,显示出112份朝天椒材料总体情况与地理分布有一定关联,但也存在区域间和省内外间的互相渗透,每个类别均聚集了不同地理来源的种质。

This study investgated the genetic diversity of Capsicum frutescens germplasm of Guizhou region in the southwest of China,provide accurate reference for the conservation,utilization and molecular marker assisted selection of Capsicum frutescens germplasm.20 SSR molecular markers were used to analyze genetic diversity of 112 Capsicum frutescens germplasm resources in the southwest of China.The results showed that 20 pairs of SSR primers amplified 65 polymorphic bands,with 2—4 loci amplified by each pair of primers,the average of effective number of alleles was 1.8294,the average of polymorphism information content(PIC)was 0.5440,the average of Shannon’s information index(I)was 0.7234,the mean values of observed heterozygosity(Ho),expected heterozygosity(He),Nei’s expected heterozygosity were 0.4920,0.4337 and 0.4318 respectively.The 20 pairs of SSR primers were highly polymorphic and could reflect the genetic diversity information among different local varieties of Capsicum frutescens.The clustering results showed that the genetic similarity coefficient(GS)value of the material population ranged from 0.5692 to 0.9538,and the average of GS was 0.7733,indicating that the genetic similarity between Capsicum frutescens local varieties was relatively high and the genetic relationship between the materials was relatively close.The materials clustered into 4 branches at GS value of 0.7670.The clustering results showed that the overall distribution of 112 Capsicum frutescens materials was related to the geographical distribution,but there was also inter regional and inter provincial infiltration,and each category gathered materials from different geographical sources.