基于ISSR标记的火龙果种质资源遗传多样性分析

为明确火龙果种质资源的遗传多样性水平和亲缘关系,以69份火龙果核心种质为研究对象,采用ISSR分子标记进行火龙果遗传分析。结果表明：13条ISSR引物共检测到247个位点,其中多态性位点数为232个,多态性条带百分比（PPB）为93.93%,平均多态性信息含量（PIC）为0.9189;平均观测等位基因数（N_a）为1.9084,有效等位基因数（N_e）为1.4606,期望杂合度（H_e）为0.2750,Nei氏基因多样性（H）为0.2616,香农信息指数（I）为0.4190。火龙果种质资源的遗传距离为0.0707~0.6741。基于遗传距离聚类分析结果,火龙果种质资源分为6大类群,第Ⅰ类群为红皮白肉类型,包括25份种质;第Ⅱ类群有19份种质,全部为红肉或紫红肉类型,包括红皮、青皮、橘黄皮类型;第Ⅲ类群包含类型较杂,包括粉肉、双色类型和水晶系列品种;第Ⅳ大类为黄皮白肉类型;第Ⅴ类和第Ⅵ类群均仅有一个种质,单独自聚一类。研究结果为火龙果种质资源的分类、保存与利用、遗传进化等研究及杂交组合选配提供理论指导和技术支持。

Genetic Characterizaiton of Pitaya Accessions based on ISSR Analysis

In order to clarify the level of genetic diversity and relationship of pitaya germplasm resources,69 core collections of pitaya were used as the research materials,and ISSR molecular markers were used to analyze the genetic characterizaiton of pitaya.The results showed that a total of 247 loci were detected by 13 ISSR primers,of which 232 loci were polymorphic.The percentage of polymorphic bands(PPB)was 93.93%,and the average polymorphism information content(PIC)was 0.9189.The average observed number of alleles(Na),effective number of alleles(Ne),expected heterozygosity(He),Nei's gene diversity(H)and Shannon information index(I)was 1.9084,1.4606,0.2750,0.2616 and 0.4190,respectively.The genetic distance varied from 0.0707 to 0.6741.Six groups were distinguished by truncating the dendrogram.Grop I contained 25 accessions,which were white pulp genotypes.Group II contained 19 red(purple red)pulp accessions,including red,green,and orange peel genotypes.Group III contained miscellaneous genotypes,including pink pulp,two-color type and crystal series varieties.Both group V and group VI had only one accession and were self-clustered,respectively.The results would provide theoretical guidance and technical support for the classification,conservation and utilization,genetic evolution and hybrid combination selection of pitaya germplasm resources.