基于SRAP分子标记构建何首乌核心种质库

Construction of core germplasm bank of Fallopia multiflora using SRAP molecular markers

关键词:  何首乌, 核心种质构建, SRAP, 遗传多样性, 居群结构

Key words:  Fallopia multiflora, construction of core germplasm, SRAP

摘要:

为保护何首乌遗传种质多样性,该文运用SRAP分子标记方法探究了44个产地327份何首乌种质的遗传多样性和居群结构,采用3种取样策略及6种比例抽样模式构建核心种质库,经t检验比较后筛选较优的核心种质构建方法和具有代表性的核心种质。结果表明:(1)何首乌种质遗传多样性较丰富,其观察等位基因数(Na)、有效等位基因数(Ne)、Shannon信息指数(I)和Nei's遗传多样性指数(H)分别为1.984 3、1.454 9、0.271 7和0.417 9,另外何首乌种质居群间遗传分化程度大,基因交流较少,基因差异分化系数(Gst)为0.753 1,基因交流值(Nm)仅有0.163 9。(2)根据样品间遗传距离,采用邻接法对样品进行聚类,聚类结果显示327份样品主要分成四大类,样品分组结果与地理分布相符,相同采集点样品可聚在同一类中。(3)居群结构分析结果显示,当K=16时,其ΔK值最大,说明样品分成16个类群时最佳,同时大部分何首乌样品的血统组成较单一(Q>0.600),相同采集点样品血统组成相似,可大致归在同一类群中。(4)t检验结果显示,采用居群结构分类-比例取样和10%抽样比例构建的种质库,4个遗传参数的保留率高,Na、Ne、I和H的保留值分别为99.0%、101.9%、106.4%和105.9%,样品量较少,且多样性与原种质库无明显差异(P>0.05)。(5)核心种质库由34份样品组成,包括9份栽培样品和25份野生样品,主要来源于四川、重庆和贵州。该研究构建的核心种质库能代表原种质库的遗传多样性,可为种质资源的收集和新品种的选育提供参考,所采用的研究方法对其他植物核心种质库的构建具有一定参考意义。

Abstract:

In order to protect the genetic diversity of Fallopia multiflora, in this study, SRAP molecular marker method was used to explore the genetic diversity and population structure of 327 F. multiflora samples from 44 habitats. Three sampling strategies and six proportional sampling modes were used to construct the core germplasm bank. After t-Test comparison, the better core germplasm construction method and the representative core germplasm samples were selected. The results were as follows:(1)The genetic diversity of F. multiflora germplasm was abundant, and number of observed alleles(Na), number of effective alleles(Ne), Shannon information index(I)and Nei's genetic diversity index(H)were 1.984 3, 1.454 9, 0.271 7 and 0.417 9, respectively. In addition, the population of F. multiflora germplasm showed a high degree of genetic differentiation, but less gene exchange, with a gene differentiation coefficient(Gst)of 0.753 1 and a gene flow(Nm)of 0.163 9.(2)According to the genetic distance between samples, the Neighbor-Joining method was used to cluster the samples. The results showed that the 327 samples were mainly divided into four categories. The grouping results were consistent with the geographical distribution, and the samples at the same collection point could be clustered into the same category.(3)Population structure analysis showed that the biggest ΔK value was obtained when K=16, indicating that the sample should be divided into 16 groups, at the same time, the lineages composition of most F. multiflora samples were relatively simple, and the samples from the same collection point had similar lineages and could be roughly grouped in the same group.(4)The t-test showed that when population structure classification-proportional sampling and 10% sampling proportion were used to construct the germplasm bank, the retention rate of the four genetic parameters was high. The retention rate of Na, Ne, I and H values were 99.0%, 101.9%, 106.4% and 105.9%, respectively, the sample size was small, and the diversity was not significantly different from the original germplasm bank(P>0.05).(5)The core germplasm bank consisted of 34 samples, including 9 cultivated samples and 25 wild samples, mainly from Sichuan, Chongqing and Guizhou provinces. The core germplasm bank constructed in this experiment can represent the genetic diversity of the original germplasm bank, and the results can provide reference for the collection of germplasm resources and breeding of new varieties. The method used in the experiment has certain reference significance for the construction of other plant core germplasm banks.