木瓜属品种亲缘关系的SRAP分析

Genetic Relationship of Chaenomeles Cultivars Revealed by SRAP Analysis

【目的】探讨木瓜属品种的种源、亲缘关系以及遗传多样性,旨在为木瓜属品种的分类提供科学依据。【方法】利用22个SRAP(sequence-related amplified polymorphism)引物组合对27份品种和5份野生种进行聚类分析、主坐标分析及遗传多样性的评价。【结果】共检测到152个多态性位点,平均每个引物组合6.91个多态性位点,多态性位点百分数为73.08%。聚类分析显示,32份材料可划分为毛叶木瓜种系、西藏木瓜、皱皮木瓜种系、日本木瓜种系4个类群。西藏木瓜与毛叶木瓜种系聚为一支,亲缘关系密切;日本木瓜种系和皱皮木瓜种系聚为另一支,日本木瓜种系与毛叶木瓜种系亲缘关系最远,皱皮木瓜种系位于日本木瓜种系与毛叶木瓜种系之间。遗传多样性分析显示,日本木瓜种系和皱皮木瓜种系的遗传多样性指数高于毛叶木瓜种系,可能与交配、繁殖方式有关。属的水平上,种系间的遗传分化系数GST=0.4969。【结论】SRAP分子标记是研究木瓜属栽培品种遗传关系的有效工具。结合形态特征和SRAP分析结果,花柱基部被毛的状态是鉴定木瓜属栽培品种种源的准确指标之一。C.×superba与皱皮木瓜亲缘关系较近,可作为皱皮木瓜种下的品种群。

[Objective] The botanical source, genetic relationship, and genetic diversity of Chaenomeles cultivars were probed. The aim is to provide a scientific basis for Chaenomeles cultivars classification. [ Method] The cluster analysis, principal coordinate analysis and genetic diversity of 27 cultivars of Chaenomeles and 5 wild species were analyzed using 22 SRAP primer combinations. [Result] A total of 152 polymorphic loci were detected among these materials with average 6.91 polymorphic loci per SRAP primer combination, and the percentage of polymorphic loci was 73.08%. The result of cluster analysis revealed that 32 materials could be divided into 4 groups, namely C. cathayensis system, C. thibetica, C. speciosa system and C. japonica system. C. thibetica appeared to be rather closely related to C. cathayensis system. C. japonica system and C. speciosa system clustered into together. C. japonica system and C. cathayensis system were the most distantly related systems. C. speciosa system took an intermediate position between C. japonica system and C. cathayensis system. Genetic diversity analysis showed that C. japonica system and C. speciosa system were more diverse than C. cathayensis system. Differences in mating and breeding systems among the species can be suggested as a possible explanation of the results. At the genus level, the coefficient of genetic differentiation among species （GST） was 0.4969. [Conclusion] SRAP molecular markers was an effective research tool for genetic relationship of Chaenomeles cultivars. Integrated morphological characters and SRAP analysis, the state of basal style hairiness was one of the accurate indicators for identification of botanical source of Chaenomeles cultivars. C. x superba was closely related to C. speciosa, and could be used as a cultivar group in C. speciosa.