中国栽培大豆(Glycine max (L.) Merr.)微核心种质的群体结构与遗传多样性

【目的】评价中国栽培大豆微核心种质的群体结构和遗传多样性水平,为拓宽大豆遗传基础、发掘优异基因、改良大豆品种提供理论依据。【方法】利用大豆20个连锁群上的100个SSR位点,对来自全国28个省补充完善的248份栽培大豆微核心种质进行SSR遗传多样性及群体结构分析;采用PowerMarker Version 3.25软件统计等位变异数、平均等位变异数、多态性信息量(PIC值)及亚群特有等位变异数等参数;基于遗传距离建立了栽培大豆微核心种质的无根Neighbor-Joining树;用Structure2.2软件对微核心种质的群体结构进行评价。【结果】100个SSR位点在248份材料中共检测出等位变异1460个,每个位点变异范围为2—33个,平均为14.6个,每个位点PIC值变异范围为0.158—0.932,平均为0.743。基于模型的群体结构分析显示,依据LnP(D)无法判断最佳K值(群组数),但通过计算系数ΔK发现,K=3为微核心种质的最佳群体结构。结合种质的生态类型及品种类型分析发现,地理来源相同的种质具有聚在一起的倾向,但来源相同的种质也有分在不同组的情况。不同生态类型及品种类型间均存在较多的互补等位变异和特有等位变异。【结论】中国栽培大豆微核心种质具有丰富的遗传多样性,可以用来拓宽大豆品种遗传基础;不同生态类型及品种类型间存在较多的互补及特有等位变异,是种质创新及品种改良的物质基础;栽培大豆微核心种质存在明显的群体结构,为微核心种质在育种中的直接或间接利用提供了理论依据。

Population Structure and Genetic Diversity of Mini Core Collection of Cultivated Soybean (Glycine max(L.) Merr.) in China

【Objective】 The population structure and genetic diversity of mini core collection of cultivated soybean in China were studied in order to provide a theoretical basis for broadening the genetic base of soybean cultivars, identifying genes interested by breeders and improving varieties. 【Method】 The mini core collections of cultivated soybean in China including 248 accessions supplemented by 28 provinces were employed for SSR analysis using 100 SSR polymorphic primer pairs to detect the population structure and genetic diversity. The PowerMarker Version 3.25 software package was used to make statistics of the number of alleles, average alleles, specific alleles and polymorphic information content. Neighbor-joining tree of mini core collection of cultivated soybean in China was revealed by using similarity coefficients based on genetic distance. Structure 2.2 software was used to evaluate the population structure of mini core collection of cultivated soybean in China. 【Result】 All of the 100 SSR loci were polymorphic across the 248 accessions and a total of 1 460 alleles were detected. The average number of alleles per locus was 14.6, ranging from 2 to 33. The average polymorphic information content (PIC) per locus was 0.743 with a range of 0.158-0.932. There was no clear genetic structure according to the Log probability of data, LnP(D). The true population structure of mini core collection of cultivated soybean in China existed at K equals to 3 through calculation of the ?K. Analysis on eco-geographical types and cultivar types suggested that the accessions from the same origin trended to be divided into the same group. But a few accessions from the same origin were divided into different groups. The specific alleles existed among different eco-geographical origin types and different cultivar types. 【Conclusion】 The genetic diversity level of mini core collection of cultivated soybean in China is much higher which can be used to broaden the genetic base of soybean. More complementary alleles and specific alleles exist among different eco-geographical origin types and different cultivar types, which can be used for germplasm innovation and improvement. Clear population structure exist in mini core collection of cultivated soybean in China which has provided theoretical guidelines for using of mini core collection in soybean breeding program.