基于SNP标记分析广西玉米地方品种遗传多样性

SNP-based Genetic Diversity Dissection of Maize Landraces from Guangxi

为了挖掘优异地方种质资源,提高广西玉米育种效率,本研究利用10KSNP芯片对169份广西玉米地方品种进行全基因组扫描,研究广西玉米地方品种的遗传多样性与群体遗传结构。结果表明,广西玉米地方品种总体的遗传多样性较高,5877个SNPs标记在169份地方品种中基因多样性平均值为0.37,多态信息含量(PIC)平均值为0.30。种群水平上,桂东北区域地方品种的遗传多样性最高(基因多样性=0.39,观察杂合度=0.27,最小等位基因频率=0.30,PIC=0.31)。群体遗传结构分析、主成分分析和进化树分析将地方品种划分为两大类群,种群间遗传关系和类群归属与地理位置不完全相关,品种杂合率差异较大且总体遗传相似系数较低。分子变异方差分析结果显示2%的遗传变异来自种群间,98%的遗传变异来自种群内。群体间遗传分化系数(F_(ST))平均为0.049,群体间遗传分化较小。研究结果确定了广西不同地理来源的玉米地方品种多态性及亲缘关系,为广西玉米种质改良和指导新品种培育提供理论依据。

In order to uncover elite local germplasm resources and improve the efficiency of maize breeding in Guangxi of China,169 maize landraces from Guangxi were genotyped using 10K SNPs in the present study,followed by their genetic diversities and population structure analysis.The results showed that the average genetic diversity and polymorphic information content(PIC)of 5877 screened SNP markers were 0.37 and 0.30,respectively,exhibiting relatively higher diversity in maize landraces from Guangxi.The landraces from Northeastern Guangxi exhibited the highest diversity level(gene diversity=0.39,observed heterozygosity-0.27,minimum allele frequency-0.30,PIC=0.31).Gained from the population structure and principal component analysis,169 landraces were divided into two major populations.The genetic relationship and structured assignment among populations were not observed correlating with their geographical originations.Besides,all landraces exhibited relatively higher heterozygosity but relatively lower genetic similarity coefficients.Analysis of molecular variance(AMOVA)showed that 2%of genetic variation was contributed by inter-population diversity,while 98%was contributed by intra-population diversity.The genetic differentiation coefficient(F_(ST))between populations was 0.049,indicating a relatively low level of genetic differentiation among populations.In summary,the present study uncovered the polymorphism and genetic relationship of maize landraces from different geographical regions of Guangxi,providing a theoretical reference for the improvement of maize germplasm and practical guidance of new variety development in these regions.