利用ISSR分子标记构建新疆野杏核心种质资源

The Core Collection Construction of Xinjiang Wild Apricot Based on ISSR Molecular Markers

【目的】通过对不同取样策略和遗传距离相结合的组合结果进行分析对比,以此探讨分子水平构建新疆野杏核心种质的方法,确定最适核心种质资源,以利于种质的保护与利用。【方法】以分布于新疆伊犁地区霍城县大西沟、新源县博尔赛和巩留县伊依克台3个分布区的135个新疆野杏实生株系为材料,根据SM、Jaccard和Nei&Li遗传距离,采用UPGMA聚类法对新疆野杏整体进行多次聚类抽样,直到其中某个采样点再次聚类时无种质被抽取;以随机取样策略为对照取样策略,应用位点优先取样策略,研究新疆野杏核心种质构建的方法;采用丢失的等位基因数以及多态性位点数、多态性位点百分率、观测等位基因数、有效等位基因数、Nei’s遗传多样性指数和Shannon信息指数各遗传多样性指标进行t检验来确定最适构建方法;分别将核心种质与原种质和保留种质进行t检验和遗传多样性比较,以此来评价核心种质的代表性;并用主坐标轴分析法和表型性状对原种质和核心种质进行分析,以此对核心种质进行确认。【结果】位点优先取样策略构建的核心种质比对照随机取样策略丢失的多态性位点数少,且同一遗传距离下位点优先取样策略构建的核心种质具有较高的遗传多样性,更能构建一个具有代表性的核心种质;通过Nei&Li遗传距离构建的新疆野杏核心种质各遗传多样指标具有较大值,优于SM和Jaccard遗传距离;采用主坐标轴分析法和表型数据分析显示,利用位点优先取样策略和Nei&Li遗传距离构建的新疆野杏核心种质能够较全面的代表野杏原种质的遗传多样性;31份野杏核心种质资源,保留了原种质22.96%的样品,多态性位点、多态性位点百分率、观测等位基因数、有效等位基因数、Nei’s遗传多样性指数和Shannon信息指数的保留率分别达到92.69%、98.83%、99.42%、103.26%、109.24%和108.31%。【结论】采用位点优先法和Nei&Li遗传距离进行多次聚类,是较适宜的构建新疆野杏核心种质的方法,构建的31份核心种质能最大程度代表原种质的遗传多样性,同时本研究所采用的方法对其他作物核心种质的构建具有重要的参考价值。

[Objective]By comparison analysis of the results of different sampling strategies and genetic distances, the method for constructing core collection of Xinjiang wild apricot based on molecular markers data was studied in order to establish the optimum core collection resources which will be beneficial to the protection and use of resources. [Method] Taking 135 wild apricots as materials that were come from Huocheng Daxigou, Xinyuan Boersai and Gongliu Yiligedai in Xinjiang, using UPGMA stepwise clustering method according to SM, Jaccard and Nei＆amp;Li genetic distances for initial collection, until any one sampling location was no collection into the core collection, then an allele preferred sampling strategy was used to construct wild apricot core＆amp;nbsp;collection and compared with the random sampling strategy. The number of lost allele and t-test of number of polymorphic loci, percentage of polymorphic loci, observed number of alleles, effective number of alleles, Nei’s genetic diversity and Shannon information index for gene diversity were used to determine the optimal building methods. T-tests of core collection, initial collection and reserve collection were conducted, and the genetic diversity of them was compared to evaluate the representative of core collections. The principal coordinate analysis method and the phenotypic traits of initial and core collections were used to confirm the core germplasm.[Result]Compared with the random sampling strategy, allele preferred sampling strategy could construct more representative core collections that with higher values of genetic diversity indexes and little polymorphic loci. According to Nei＆amp;Li genetic distance, the constructed core collection of Xinjiang wild apricot was better than by SM and Jaccard genetic distance for these core collections had high values of genetic diversity indexes. The analysis of principal coordinate analysis and phenotypic traits showed that the core collection of Xinjiang wild apricot constructed by allele preferred sampling strategy and Nei＆amp;Li genetic distance could more comprehensively represent at the genetic diversity of wild apricot initial collection. The 31 core collection resources of wild apricot includes 22.96%germplasm samples of the initial collection, the retention ratio of number of polymorphic loci, percentage of polymorphic loci, observed number of alleles, effective number of alleles, Nei＆#39;s genetic diversity and Shannon information index were 92.69%, 98.83%, 99.42%, 103.26%, 109.24%and 108.31%, respectively. [Conclusion]The method of allele preferred sampling strategy and Nei＆amp;Li genetic distance by stepwise clustering is a suitable method for constructing Xinjiang wild apricot core collection. These results demonstrated that the 31 core collection could stand for original collection excellently, at the same time this research method of the construction of core collection has important reference values for other crops.