香蕉种质资源亲缘关系的ISSR分析

利用ISSR标记对3个基因型(AAA,AA和ABB)共35份香蕉种质资源的遗传多样性和亲缘关系进行了分析,筛选出的6条ISSR引物共扩增出38条带,扩增片段长度为200～2 000bp,27条具有DNA多态性,多态性为71.05%,遗传距离为4.30%～33.33%。用UPGMA聚类分析结果显示,以遗传距离25%为阈值,35份香蕉种质可分成6个类群,除贡蕉(AA)和金粉1号(ABB)分别归为Ⅲ和Ⅳ两个类群之外,其余33份种质分为4个类群,其中Ⅰ类群包含着来自不同地方的基因型为AAA和ABB的22份香蕉种质。基因型为AAA和ABB的香蕉种质并不被简单地划分成两类,部分基因型相同的香蕉种质之间没有表现出紧密的亲缘关系。本研究所用的6条引物能把香蕉种质区分开,ISSR分子标记对研究香蕉种质资源的亲缘关系是有效的。

Genetic Relationship among Banana(Musa spp.) Germplasms Revealed by ISSR Analysis

Genetic diversity and relationship among 35 banana germplasms involving 3 genotypes(i.e.,AAA,AA and ABB) were studied by using the Inter-Simple Sequence Repeat(ISSR) method.As a result,6 ISSR primers were selected,38 bands amplified between 200 bp and 2,000 bp,27 bands detected for polymorphic DNA,and the percentage of polymorphic DNA 71.05% of polymorphic DNA were found.The genetic distances among the banana cultivars were between 4.30% and 33.33%.A cluster analysis was performed applying the unweighted pair group method on arithmetic averages.The banana germplasms were grouped into 6 clusters based on the genetic distance of 25%.Except for Gongjiao(AA) and Jinfen1(ABB),which were grouped into Cluster III and IV,respectively,the remaining 33 germplasms were classified into 4 clusters,in which Cluster I contained 22 germplasms from different localities and genetypes(AAA and ABB).All germplasms with genotypes AAA and ABB could not be divided into 2 clusters.There appeared no close genetic relationship among some banana germplasms with same genotypes.The germplasms could be discriminated by the 6 selected primers,and ISSR was considered as an effective method for studying genetic relationship among different banana germplasms resources.