基于cpSSR标记的山药种质资源DNA指纹图谱构建及遗传多样性分析

采用叶绿体SSR(cpSSR)分子标记对从国内外引进的64份山药种质资源进行遗传多样性分析,构建DNA指纹图谱,旨在为山药品种亲本选择,山药种质创新及品种改良提供依据。结果显示:从21对cpSSR引物中筛选出10对扩增稳定、多态性高的引物,在64份山药种质材料中扩增出69个条带,多态性条带59个,多态性比率高达85.51%,平均观测等位基因数(Na)为2,平均有效等位基因数(Ne)为1.569 3(1.231 1~1.916 0),平均Shannon信息指数为0.560 6(0.329 0~0.671 1),平均Nei’s基因多样性指数(He)为0.378 1(0.184 8~0.478 1),表明64份山药种质资源具有丰富的遗传多样性。聚类分析结果表明,遗传相似系数变幅为 0.55~0.93,在相似系数为 0.63时,可将64份山药种质资源分为4类,结果表明,基于cpSSR 分子标记的山药种质资源的分类在种间具有较好的区分能力,但是cpSSR 分类表现出较大的地理分布的相关性,而与形态特征关系不密切。选用较少的引物区分较多的品种为原则,采用2对引物成功构建供试种质的DNA指纹图谱,为山药种质资源鉴定和品种选育亲本的选择提供理论依据。

Genetic diversity analysis and construction of DNA fingerprint of yam (Dioscorea oppositeac Thunb.) germplasm by cpSSR marker

In order to provide molecular foundation for the innovative parental selection and the varieties improvement of Dioscorea oppositeac Thunb. germplasm, in present study, the molecular fingerprints of 64 accessions of D. oppositeac from home and abroad were mapped and the genetic diversity was analyzed using cpSSR molecular markers technology. The results showed that 10 pairs of primers were selected from 21 pairs of cpSSR primers.The genome DNA of 64 accessions of D. oppositeac germplasm were amplified by 10 pairs of cpSSR primers with stable amplification, high polymorphism selected from 21 pairs of primers. Sixty-nine bands were got totally, of which 59 were polymorphic bands, and the rate of polymorphic bands reached as high as 85.51%. The average number of observed alleles (Na) was 2, the mean effective allele (Ne) was 1.569 3 (1.231 1-1.916 0), and the average Shannon’s information index was 0.560 6(0.329 0-0.671 1), the average Nei’s genetic diversity index (He) was 0.378 1 (0.184 8-0.478 1),indicating a rich genetic diversity. Based on genetic similarity coefficient (GS), which ranged from 0.55 to 0.93, the phylogenetic relationships of 64 D. oppositeac germplasm resources were analyzed. When the threshold value of genetic similarity coefficient was 0.63, all the tested materials could be clustered into 4 classes. With the principle of identifying 64 D. oppositeac germplasm resources with a minimum number of primers, 2 pairs of primers were used to successfully construct DNA fingerprint.