黄瓜种质资源遗传多样性的RAPD鉴定与分类研究

Genetic Diversity and Phylogenetic Relationship of Cucumber (Cucumis sativus L.) Germplasm Based on RAPD Analysis

利用 2 9个RAPD引物对 6 6份来源和类型不同的黄瓜种质基因组DNA的分析 ,共扩增出了 2 5 3条带 ,其中 195条为多态性带 ,比例为 77 0 8%。不同引物所揭示的种质多样性差异很大。供试种质间平均期望杂合度为 0 388。中国种质的平均期望杂合度为 0 348,略高于国外引进种质。长江以南黄瓜种质的遗传多样性高于长江以北 ,华南型种质的遗传多样性高于华北型种质。长江流域以南可能是黄瓜的较早或主要的演化地。供试种质依RAPD标记被分为 8个组群。西双版纳黄瓜明显地与其他栽培种质分开了 ,国外引入的绝大多数种质被聚到一起或分属单独组群。除西双版纳外其他中国栽培种质的遗传关系与形态特征和地域分布虽然存在一定的相关性 ,但不总是一致 。

In this study, the genetic diversity among 66 cucumber accessions from different countries or regions was assessed by means of RAPD makers, and the genetic relationship among the accessions was revealed by cluster analysis. A total of 253 scorable bands were detected with 29 informative RAPD primers among 66 accessions. Of them, 195 bands (77 08%) were polymorphic. The diversity shown by different primer was greatly different. The average heterozygosity of RAPD loci in 66 accessions was 0 388. The heterozygosity of Chinese germplasm was slightly higher than that of the exotic accessions. The accessions from south China were more diverse than that from north China. The genetic diversity of south China′s ecotypes was higher than that of north China′s ecotypes. This implies that the south China may be the primary region of evolution of cucumber.66 accessions could be clustered into eight groups based on RAPD data by cluster analysis. Accessions from Xishuangbanna could be distinguished from other germplasm, and the exotic germplasm went into the same group or independent group. There was not certain association between the molecular genetic relationship revealed by RAPD markers and the morphological similarity and geographical distribution, especially among the Chinese cultivated accessions.