【作者】 刘超；

【导师】 屈淑平；

【作者基本信息】 东北农业大学 ， 蔬菜学， 2012， 硕士

【摘要】 籽用南瓜是葫芦科南瓜属中食用种子的栽培品种的总称,俗称南瓜籽,主要包括印度南瓜(Cucurbita maxima)、美洲南瓜(Cucurbita pepo)和中国南瓜(Cucurbita moschata)三个栽培种,籽用南瓜是我国特有的种质资源,黑龙江省是我国籽用南瓜的主产区。开展籽用南瓜种质资源遗传多样性的分析,为其亲缘关系、遗传多样性分布、亲本选配以及分类地位的研究提供理论依据,有利于南瓜种质资源的收集、保存、鉴定、合理利用以及种质创新。本研究利用形态学标记及SSR分子标记技术对76份生态类型不同、地理来源不同籽用南瓜种质的遗传多样性及亲缘关系进行探讨,结果如下：植物学性状遗传多样性参数的统计分析结果显示：44个植物学性状(16个数量性状和28个质量性状)的平均变异系数为15.15%,变异系数的变幅为3.79%-37.95%。质量性状的平均变异系数为17.40%,其中瓜型的变异系数最大,为37.95%,变异系数最小的性状为种子周缘颜色,仅为3.79%；数量性状的平均变异系数为16.76%,单瓜重的变异系数最大,出仁率的变异系数最小,分别为21.35%和4.18%。44个性状变量的平均Shannon多样性指数为1.26,数量性状的多样性指数大于质量性状,分别为2.08和0.82。质量性状中老瓜瓜皮颜色的Shannon多样性指数最大,为1.72,瓜梗质地最小仅为0.21；数量性状中,各性状的多样性指数的变幅为1.22-2.57,性状瓜脐直径多样性指数最大、子叶长最小。基于植物学性状的聚类分析将76份供试种质美洲南瓜和印度南瓜2个类群,每个类群内种质又按照地理来源进行了进一步分类,聚类分析结果比较好地反映了南瓜种质间的形态相似性及其与地理区域之间的关系。主成分分析前三个坐标的累计方差贡献率为41.86%,主成分分析对供试种质的分类结果与聚类分析基本一致。利用35对SSR引物对76份生态型不同、来源不同的籽用南瓜种质资源进行SSR检测,共扩增出85条带,多态带为73条,多态率为85.89%,平均每对SSR引物扩增出2.43条带和2.09条多态带。35对引物的平均Shannon多样性信息指数为0.86,其中引物CMTp208的Shannon多样性信息指数最大为1.77,CMTp177、CMTm8、CMTm66、CMTm170的Shannon多样性信息指数最小,仅为0.39。基于SSR分子标记的聚类分析,供试的76份种质的遗传相似系数变幅为0.24-0.99,种质按照生态类型被分为2类,即印度南瓜和美洲南瓜,与形态学标记聚类分析结果相同,对于类群内部,SSR标记能够准确地将种质依据来源进行分类。SSR标记的主成分分析结果显示,第一、第二、第三主坐标的方差贡献率分别为50.97%、9.14%和5.61%,累计方差贡献率为65.72%,前三个主成分基本上可以代表原始变量的全部信息。此分类方法亦将供试种质按照生态类型不同进行划分,对于美洲南瓜没有明显地区分出来源地不同的种质资源,对于印度南瓜很好地区分出了中国本土和俄罗斯种质资源,来源相同的材料遗传相似系数较高,说明亲缘关系较近。将形态学标记和SSR分子标记聚类分析结果用NYSTS软件中的进行Mantel(一致性)检验,相关系数r为0.7295,说明两种标记在本研究中对供试材料的分类具有较高的一致性。综合两种标记系统的分析结果,供试种质的亲缘关系表现为：不同生态类型种质间的亲缘关系较远,同一生态型中来源不同的资源间的亲缘关系较远,反之则较近。更多还原

【Abstract】 Used-seeds pumpkin is the general term of the Cucurbitaceae Cucurbita cultivars, mainly three varieties includingCucurbita maxima, Cucurbita pepo, Cucurbita moschata, used-seeds pumpkin is special germplasm resources in China, heilongjiang province is the grain of used-seeds pumpkin.The study on the genetie diversity of Cucurbita offer theoretical foundation for analysis of genetic relationgship, distribution of genetic diversity, parent selection and classification.It also can benefit conservation, classification, identification, genetie enhancement and effeetive utilization of the Cucurbita germplasm resources.In this study, the genetic diversity in76Cucurbita accession form different origin and type were assessed via morphological descriptors and SSR marker, The main results were as follows:In order to assess genetic diversity of76Cucurbita gennplasm, a total of44morphologieal descriptors (16quantitative and28qualitative)were measured.The average coeffieient of variation was15.15%, ranging from3.79%to37.95%.They ranged from3.79%in circumference colour of seed to37.95%in fruit sharp based on the28quantitative descriptors and from4.18%in the ratio of kernel to21.35%in fruit weigh based on the16qualitative deseriptors. The average coeffieient of quantitative deseriptors and qualitative deseriptors were17.40%and16.76%.The average Shannon’s Information index among the accessions was1.26based on the data of44morphological deseriptors.They varied from0.21to1.72based on quantitative deseriptors. And from1.22to1.57based on qualitative descriptors. All the results above confirmed that the Shannon’s Information index based on qualitative deseriptors was higher than those based on quantitative deseriptors.The76Cucurbita germplasm were clustered into2groups based on the morphological data. The first group is C. pepo and the second group was C.maxima.In every group the germplasm were devide from the origin, practically all the germplasm which were from the same origin were joined in a group. The results of hierarchical cluster analysis reflected the connection of morphologieal descriptors and geographical distribution.The results of principal components analysis showed accumulative variance contribution of the first three principal components was41.86%. The results of hierarchical cluster analysis were in accord with principal components analysis.In the study, the genetic diversity in Cucurbita accessions from different couniries or regions was assessed by SSR marker.35sereened primers produeed85seorable and repeatable SSR bands, of which73bands(85.89%) were polymorphic across87Cucurbita accessions.A mean of2.43 bands and2.09polymorphic bands per primer pair was detected.The average Shannon’s Information index of SSR loci was0.86,ranging from0.39to1.77.87Cucurbita germplasm were clustered into4groups based on the SSR data by the method of hierarehical cluster analysis, that was C. pepo, C.maxima, C. moschata and C. ficifolia.The resuts almost accorded with morphologieal traits.Genetic similarity coefficient was ranged from0.44to0.99. Internal group the germplasm were classified by the regions.The result of principal components analysis showed that accumulative variance contribution first three prineipal components was70.40%, hat basically represented information of the original variables.Through principal components analysis all the germplasm were distinguished by type, the same type internal.The same source materials, genetic similarity coefficient was high, indicating the closer relationship.Comparison of the data obtained by morphological markers and molecular makers was made by the method of Mantel test.The correlation value scope was0.7295between the morphological markers and molecular markers.The result showed that there were some differenee and also some comparability between the genetic relationship among Cucurbita accessions revealed by SSR and that by morphological markers.更多还原