玉米粒厚全基因组关联分析及全基因组选择研究

Genome-Wide Association Study of Kernel Thickness in Maize and the Genome-Wide Selection

本研究以多亲本双单倍体(DH)群体为供试材料,结合48k液相探针捕获技术,利用Blink和Farm CPU两种全基因组关联分析(GWAS)模型对玉米粒厚进行全基因组关联分析和全基因组选择,挖掘控制粒厚的显著单核苷酸多态性位点(SNP),探讨不同训练群体大小、标记密度、显著SNP标记对全基因组选择(GS)预测精度的影响。结果表明,玉米粒厚遗传力为73.68%,粒厚与穗长、穗粗和果穗重等穗部性状间均存在显著性相关关系。标准线为P<3.17×10^(-5),共鉴定出11个与粒厚显著相关的稳定标记,主要分布于1、2、3、4、5和6号染色体中,其中3_195730561标记被两个模型同时检测到。鉴定到14个候选基因,其中Zm00001d032096和Zm00001d002641基因在玉米粒厚性状细胞发育中发挥重要作用。全基因组选择结果显示,当标记数量为500、训练群体占总群体70%时,即可得到较好的GS预测精度,显著SNP标记可以提高预测精度。

In this study,we used a polyparental double haploid(DH)population as the test material,combined it with 48k liquid-phase probe capture technology to conduct genome-wide association analysis and genome-wide selection for maize kernel thickness using two genome-wide association analysis(GWAS)models,namely Blink and Farm CPU,to mine significant single nucleotide polymorphisms(SNP)controlling kernel thickness,and to explore the effects of different training population sizes,marker densities,and significant SNP markers on the prediction accuracy of genome-wide selection(GS).The results showed that the heritability of maize kernel thickness was 73.68%,and there were significant correlations between kernel thickness and ear traits such as ear length,ear thickness and cob weight.The threshold line was P<3.17×10^(-5),a total of 11 stable markings significantly associated with kernel thickness were identified,mainly in chromosomes 1,2,3,4,5 and 6,of which markings 3_195730561 was detected simultaneously by both models.Fourteen candidate genes were identified,among which Zm00001d032096 and Zm00001d002641 genes played important roles in the cellular development of maize kernel thickness trait.The results of genome-wide selection showed that good GS prediction accuracy could be obtained when the number of markers was 500 and the training population accounted for 70%of the total population,and significant SNPs could improve the prediction accuracy.