摘要：

为了在表型和分子层面分析中国南瓜×印度南瓜种间杂种拓宽南瓜遗传背景的可能性,利用30个表型性状和20对SSR分子标记,同时对当前市售食用南瓜品种、宁波市农业科学研究院多年积累的骨干亲本、以及中印南瓜种间杂种自交系及其新配组合共53份南瓜材料进行遗传多样性分析。结果表明,骨干亲本和中印南瓜种间杂种后代在株型、生长势、果实皮色、果型等方面增加了南瓜品种多态性的丰富度。20个SSR标记在53份南瓜材料的多态性比例为90%。在主成分分析的基础上,表型聚类和分子聚类的结果吻合度提高。2种方法3次聚类的结果都将供试印度南瓜商品种及骨干亲本聚为一类,表明其相似度较高,同质化严重,不利于培育突破性品种。其次,聚类结果都将中印南瓜远缘杂交后代及组合单独聚为一类,与印度南瓜商品种、印度南瓜骨干亲本,以及中国南瓜材料显著分开。表明中印南瓜远缘杂交后代无论在分子层面还是表型层面都与供试南瓜品种和育种材料有显著差异,增加了南瓜的遗传多样性。通过种间杂种,可以为食用南瓜新品种选育提供异质基因。主成分分析获得的6个主成分因子,可简化食用南瓜性状调查指标。

关键词: 南瓜, 种间杂种, 商品种同质化, 遗传多样性, 聚类分析

Abstract:

To investigate the genetic polymorphism of the inbred lines and hybrids derived from Cucurbita moschata (MO)×Cucurbita maxima (MA),the genetic diversity of 53 pumpkins,including commercial varieties,core parent materials and inter-specific hybrids offspring,were investigated by thirty morphological traits and twenty SSR markers.The results showed that the core parent materials and offspring of inter-specific hybrids had more polymorphism in plant type,growth vigor,fruit skin color and shape than commercial varieties.Twenty SSR primers were screened and showed 90% of polymorphism ratio.Based on the principal components,the cluster results of morphological and SSR markers were consistent with each other very well.The two methods and three times cluster results showed that the commercial varieties and core parent materials of Cucurbita maxima were clustered into one group,firstly.This mean the commercial varieties and core parent materials of Cucurbita maxima had relatively close genetic distance and shared the severely homogenized genetic background.It's very hard to produce the new and different varieties in this situation.Secondly,the offspring of inter-specific hybrids derived from MO×MA were clustered into one group,which was distinguished from commercial varieties and core parent materials of Cucurbita maxima and the genotypes of Cucurbita moschata.The offspring of inter-specific hybrids had relatively long genetic distance and more polymorphism than commercial varieties.It's possible to derive the new and different pumpkin varieties by crossing with the genotypes having the heterogeneous genes produced from interspecies hybrids.Meanwhile,the 6 principal component factors derived from principal component analysis would be used to simplify the edible pumpkin survey indicators.

Key words: Pumpkin, Inter-specific hybrids, Commodity homogenization, Genetic diversity, Cluster analysis