黄瓜种质资源遗传多样性及其亲缘关系的AFLP分析

 采用AFLP分子标记技术，对中国黄瓜种质资源遗传多样性及其与外来种质的关系进行了分析， 结果表明8对AFLP引物在70份黄瓜种质中共扩增出425条带，多态性带的比例为66％。供试黄瓜种质的平 均期望杂合度为0．376，中国种质的平均期望杂合度为0．387，明显高于国外种质的n 291。西双版纳黄瓜和印度野生黄瓜具有一些栽培种质没有的特异位点，中国栽培种质的特异位点多于外来栽培种质，后者也有一些中国栽培种质没有的特异位点。聚类分析将70份种质分为三大组群，即西双版纳黄瓜(Cucumis sativus L.vaF．xishuangbannanesis Qi et Yuan)组群，e sativus var．hardwickii野生黄瓜组群和栽培黄瓜组群。西双版纳黄瓜与栽培黄瓜的距离最远，与野生黄瓜次之。按一定的遗传距离可以将中国和外来栽培种质分开。大多数 华南型和华北型种质归属于不同的亚组。这些结果有助于有目的地利用这些变异拓宽育种材料的遗传背景。

Studies on Genetic Diversity and Phylogenetic Relationship of Cucumber(Cucumis sativus L.) Germplasm by AFLP Technique

In this study, genetic diversity in 70 accessions of Cucumis sativus L. from different countries or regions was assessed using AFLP markers, and the genetic relationship among the accessions was revealed by cluster analysis.Eight pairs of AFLP informative primers generated 425 scorable bands in total, 66% of which were polymorphic. The average expected heterozygosity of AFLP loci among all accessions was 0 376.The heterozygosity among Chinese accessions was higher than that among exotic accessions. C. sativus L. var. xishuangbannanesis Qi et Yuan and India wild germpalsm had some special loci that were not present in cultivars.The special loci in China cultivars are more than that in the germplasm from America and Europe.The exotic germplasm also has some special loci that was absent in Chinese germpalsm.Three groups were clustered based on AFLP markers, namely C. sativus L. var. xishuangbannanesis Qi et Yuan group, C.sativus var. hardwicki group and cultivars group. C. sativus L.var. xishuangbannanesis Qi et Yuan was the farthest from cultivars. India wild cucumber was the farther from cultivars. At certain distance, Chinese cultivars could be differentiated from the exotic germplasm.Most south China ecotypes and North China ecotypes could be grouped into different subgroups but a few different ecotypes went into a same subgroup.These results are beneficial for us to use various target variants to widen the genetic background of cucumber cultivars.