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为提高育种效率以及开展重要 QTL 和关键基因关联性分析研究, 以 187 份生产上重要玉米自交系为材料, 以 70 个均匀分布于全基因组简单重复序列(SSR)基因座鉴定出的290个等位基因多态性为分析数据, 采用联合连锁位点与混合模型分析, 推测这些自交系的基因组血缘构成以及分子亲缘关系, 并分析了全基因连锁不平衡。当亚群数目 K=5 时, 导致似然值 P 明显下降, 亚群数据 K > 6 时, 似然值 P 没有明显上升, 表明群体结构的亚群数 K 最佳推测为 6。六个亚群分别为 PA、BSSS (含 Reid)、PB、兰卡斯特 (Lancaster)、旅大红骨 (旅大红骨及其衍生系)、四平头 (唐四平头及其衍生系)。亚群间的Kullback-Leibler 距离自 0.13 至 1.06 不等, 平均为 0.599, 各亚群间区分度较好。全基因组连锁不平衡(LD)分析表明: 与四平头种质类群内相比, 遗传基础宽泛种质的基因组内存在 LD“区块”(LD block)少且小, 对重要 QTLs 与基因的关联性分析可以避免假阳性。本研究群体结构与基因组构成分析数据为这些材料育种应用与改良提供了重要信息, 也为基于这些材料的关联性分析奠定了分析基础。
In order to improve the breeding efficiency and carry out the analysis of the important QTL and key gene association, 187 important maize inbred lines were used as material, and 70 of 290 maize genotypes homogeneously distributed in genome-wide simple repeat (SSR) Allele polymorphism analysis data, the combination of linkage sites and mixed model analysis, speculated that these inbred lines of the genome and molecular genetic relationship, and analyzed the whole genetic linkage disequilibrium. When the number of subgroups K = 5, the likelihood P decreased obviously. When the subgroup data K> 6, the likelihood P did not increase significantly, indicating that the subgroup number K of the population structure was best estimated to be 6. The six subgroups are PA, BSSS (including Reid), PB, Lancaster, Luda Honggu (Luda Honggui and its derivatives), Siping Head (Tang Siping Head and its derivatives). The Kullback-Leibler distance between subgroups ranged from 0.13 to 1.06 with an average of 0.599. Genome-wide linkage disequilibrium (LD) analysis showed that compared with within the tetraploid germplasm, there was less and less LD block in the broad-based germplasm of the genetics and significant differences between the major QTLs and the genes Correlation analysis can avoid false positives. The data of population structure and genomic analysis in this study provided important information for the application and improvement of breeding of these materials, and laid the foundation for the analysis of the association based on these materials.