香蕉种质资源的SRAP遗传多样性分析

Genetic Diversity Analysis of Banana Germplasms Based on SRAP Molecular Markers

采用SRAP分子标记对21份香蕉种质的遗传多态性进行分析。从648对引物中筛选出38对多态性强、条带清晰的引物,共扩增出215条谱带,其中多态性条带210条,占总带数的97.67%。平均每个引物扩增的DNA带数是5.66条,多态性带数是5.33条。供试香蕉种质的遗传相似系数范围为在0.414~0.963之间,平均相似系数为0.725。UPGMA法构建的系统树和主坐标分析(PCA)结果基本一致:21份香蕉材料可划分为3个类群,除尖苞蕉(AA)和粉蕉(ABB)分别归为Ⅱ和Ⅲ两个类群之外,其余17份种质归为第Ⅰ类群,包含14份香芽蕉(AAA)、2份大蕉(ABB)及1份金手指(AAAB)。基因型为AAA和ABB(大蕉)的供试香蕉种质并不被简单地划分成两类,且部分基因型相同的香蕉种质之间也没有表现出紧密的亲缘关系。另外,供试香蕉种质对枯萎病的抗感性与其聚类群之间也没有明确的相关性。

Genetic diversity among 21 banana germplasms were analysised by using the sequence-related amplified polymorphism（SRAP） markers. The results showed that 38 primer pairs with high polymorphism and clear bands were screened from 648 primers pairs. 210 bands showed polymorphism in 215 DNA fragments and accounted for 97.67%. The average number of DNA bands produced by each primer pairs was 5.66 and polymorphic bands were 5.33. The result of genetic similarity analysis of 21 banana germplasms showed that the Nei＇s coefficient ranged from 0.414~0.963, and the average Nei＇s coefficient was 0.725. The unweighted pair group method with arithmetic mean（UPGMA） cluster analysis and principal component analysis（PCA） have similar results： tested 21 germplasms were divided into 3 groups. Except for Jianbaojiao（AA） and Fenjiao（ABB）, which were grouped into clusterⅡ and Ⅲ, respectively, the remaining 17 germplasms were classified into cluster Ⅰ： 14 germplasms from Xingyajiao（AAA）, 2 germplasms from Dajiao（ABB） and 1 germplasm from Goldfinger（AAAB）.All germplasms with genotypes AAA and ABB（Dajiao） could not be divided into 2 independent clusters. There was no close genetic relationship among some banana germplasms with same genotypes. Furthermore, it also showed that disease-resistant banana germplasms to Fusarium oxysporum f. sp. cubense race 4 had no clear relationship with their genetic diversities.