基于40个核心SSR标记揭示的820份中国玉米重要自交系的遗传多样性与群体结构

Genetic Diversity and Population Structure of Important Chinese Maize Inbred Lines Revealed by 40 Core Simple Sequence Repeats (SSRs)

【目的】选择有代表性的材料进行遗传多样性与群体结构的解析是进行等位基因发掘、复杂性状关联分析、研究,及作物育种实践的重要基础。【方法】利用覆盖玉米全基因组的40个核心SSR标记,采用基于测序的基因型鉴定技术对820份代表中国玉米育种资源种质基础的自交系进行全基因组扫描,通过PowerMarker V3.25与Structure V2.3.3等软件揭示其基因多样性与群体结构。【结果】在820份自交系中,40个SSR标记所检测到的等位变异为10—72个,平均36.87个/位点;基因多样性为0.46—0.9458,平均0.8430;PIC为0.43—0.94,平均0.83。聚类分析表明,K=5时,△K值最大,即这些自交系可以划分成5个类群,依次为兰卡斯特、旅大红骨、塘四平头、瑞德与P群,各类群内平均等位变异与遗传多样性分别为24.23个/位点与0.8145、22个/位点与0.8398、11.8个/位点与0.7054、17.45个/位点与0.7686以及14.65个/位点与0.7495。【结论】中国玉米自交系在育种实践中形成了相对独立的优势类群,蕴含了比较丰富的遗传变异,显示出了较高水平的基因多样性。不同类群之间的遗传多样性水平存在一定的差异,在划分的5个类群中,兰卡斯特与旅大红骨类群的遗传变异相对较丰富,基因多样性相对较高,其次为瑞德与P群,塘四平头相对较低。

【Objective】Genetic assessment,i.e.gene diversity and population structure,of representative accessions is of great importance in the utilization of these germplasm,allele mining,and analysis of association mapping.【Method】Forty core SSRs developed for the fingerprinting and uniformity analysis of Chinese maize varieties,covered the entire maize genome,were used to genomic scanning of a total set of 820 maize inbred lines across China by the genotyping technology based on fluorescence sequencing.The genetic diversity of these inbred lines was performed via the software PowerMarker V3.25,and the population structure of these materials was revealed by Structure V2.3.3.【Result】Among 40 SSRs,the No.of alleles of these 820 inbred lines averaged 36.87,ranging from 10 to 72,the gene diversity averaged 0.8430,ranging from 0.46 to 0.9458,and the PIC averaged 0.83,ranging from 0.43 to 0.94.Result from the clustering analysis based on a model-based method indicated that these 820 assays could be divided into 5 groups,including Lancaster,Lüda red cob（LRC）,Tang si ping tou（TSPT）,Reid（PA and BSSS）,and P group（or PB）.The corresponding average allele no.per locus of these 5 groups was 24.23,22,11.8,17.45,and 14.65,and the gene diversity was 0.8145,0.8398,0.7054,0.7686,and 0.7495,respectively.【Conclusion】Results revealed by the core SSRs showed a relatively higher abundant genetic variation and a rather high level of gene diversity,while significant difference existed among 5 groups.Diversity level of Lancaster and LRC was statistically higher than that of Reid,TSPT,and P,and groups of TSPT and P possessed relatively lower genetic diversity.