新疆甜瓜地方种质资源遗传多样性的SRAP分析

为研究我国新疆甜瓜地方种质资源亲缘关系及其分类,充分高效的利用种质资源,利用SRAP(sequence-related amplified polymorphism technique)标记对117份中国新疆甜瓜地方品种和28份国内外对照材料进行亲缘关系和遗传多样性分析。结果表明,20对SRAP引物共扩增出224个带,其中多态性谱带216个,多态性比率达96%,平均每对引物扩增的带数和多态性带数分别为11.2个和10.8个,每对引物的多态性信息含量PIC值为0.73~0.94,平均为0.85;不同生态区域供试材料的Nei's基因多样性指数(H)和Shannon's信息指数(I)分别为0.1075~0.2560和0.1569~0.4061,中国新疆的南疆、东疆和北疆均高于其他生态区域供试材料,且以南疆最高,具有非常丰富的遗传多样性;不同生态区域甜瓜种质资源的遗传一致度和遗传距离分别为0.6384~0.9919和0.0081~0.4488,其中南疆、东疆和北疆两两之间的遗传一致度均在0.95以上,遗传距离均在0.04以下,三者之间遗传分化较小;中国新疆甜瓜与印度、西亚、西班牙的甜瓜种质资源亲缘关系较近,与韩国、日本、美国和前苏联的甜瓜种质资源亲缘关系较远。聚类分析结果表明,以遗传相似系数0.548为阈值,145份种质材料可分为3大类群;厚皮甜瓜与薄皮甜瓜间在分子水平上没有严格的界限,两者之间亲缘关系的远近在不同的种质材料间差异很大;117份中国新疆甜瓜地方种质资源可分为A(Ⅰ-1)、B(Ⅰ-2、Ⅰ-3、Ⅰ-5)、C(Ⅰ-6)、D(Ⅱ)等4大类6个亚类群,与传统4个变种10个品种群分类结果不同,但在每个大类或亚类群中属于同一变种或品种群的材料倾向于聚在一起。

Genetic diversity analysis of melon landraces (Cucumis melo L.) in Xinjiang based on SRAP markers

The phylogenetic relationship and genetic diversity among 145 melon accessions,including 117 China's Xinjiang landraces and 28 exotic melon germplasms collected from abroad and eastern China,were analyzed based on sequence-related amplified polymorphism technique (SRAP).Two-hundred and twenty-four bands were identified by 20 pairs of SRAP primers in total.Among them,216 bands were polymorphic with the polymorphic rate 96％.And 11.2 bands and 10.8 polymorphic bands were amplified by each pair of primer on average.The polymorphism information content(PIC) with each pairs of primer was between O.73 and O.94,and the average was O.85.The genetic diversity index (H)and Shannon's information index(Ⅰ) of accessions in different ecological regions ranged from 0.1075 to 0.2560 and from 0.1569 to 0.4061,respectively.Whether H and I of southern Xinjiang,eastern Xinjiang or northern Xinjiang,which were higher than other ecological regions,in which the southern Xinjiang was highest.These results suggested that there was rich genetic diversity among the melon landraces collected from various parts of Xinjiang.The values of genetic identity and genetic distance between any two distinct ecological regions were 0.6384-0.9919 and 0.0081-0.4488,respectively.The values of genetic identity were above 0.95 among northern Xinjiang,southern Xinjiang and eastern Xinjiang,and in which the values of genetic distance were below 0.04,the genetic differentiation in three ecological regions was low.The relationship of melon accessions was from Xinjiang of China,Western Asia,India and Spain were near with each other while it had a distant relationship for Xinjiang with Korea,Japan,the Untied States and the former Soviet republics.Three groups were clustered for 145 melon accessions according to genetic similarity coefficient of 0.548.There was no distinct boundary between thick-skinned melon and thin-skinned melon.The genetic relationship of thick-skinned melon and thin-skinned melon was quite different with different germplasm materials.117 China's Xinjiang landraces can be divided into four categories and six subgroups,as A (Ⅰ-1),B (Ⅰ-2,Ⅰ-3,Ⅰ-5),C (Ⅰ-6) and D (Ⅱ),which was different from the clustering result based on SRAP markers and the classification result according to the characters of melon mature period,the fruit shape and fruit surface.But the melon accessions which belonged to the same variety or cultivar group were tending to in the same cluster based on SRAP markers.