抽穗重(TW)是玉米育种中重要的农艺性状,显著影响花粉供应和籽粒产量发育。提高玉米产量,培育新品种,全面了解流苏重量的遗传机制至关重要。在这项研究中,热带玉米自交系,即CML312,CML373,CML444和YML46被选为雌性亲本,并与优良玉米自交系Ye107杂交,后者是共同的雄性亲本,开发包含四个F8重组自交系(RIL)亚群的多亲本群体。使用6616个高质量的单核苷酸多态性(SNP)标记,我们在3种不同环境的4个亚群中对642个F8RIL进行了全基因组关联分析(GWAS)和基因组选择(GS).通过GWAS,我们确定了16个与TW显著相关的SNP,包含在多个环境中表达的两个稳定基因座。此外,在这些SNP的候选区域内,我们发现了四个与TW相关的新候选基因,即Zm00001d044362、Zm00001d011048、Zm00001d011049和Zm00001d031173分布在1号、3号和8号染色体上,以前没有报道过。这些基因参与信号转导等过程,成长和发展,蛋白质剪接,和花粉发育,所有这些都在花序分生组织发育中起着至关重要的作用,直接影响TW。共同定位的SNP,S8_137379725,在8号染色体上位于16.569kb长的末端重复反转录转座子(LTR-RT)内,位于候选基因上游22.819kb和下游26.428kb(Zm00001d011048和Zm00001d011049)。比较三种不同的GS型号时,贝叶斯B模型在预测TW方面表现出最高的准确性。本研究为今后研究玉米TW的遗传机制以及通过GS高效选育期望穗重的高产品种奠定了理论基础。
Tassel weight (TW) is a crucial agronomic trait that significantly affects pollen supply and grain yield development in maize breeding. To improve maize yield and develop new varieties, a comprehensive understanding of the genetic mechanisms underlying tassel weight is essential. In this
study, tropical maize inbred lines, namely CML312, CML373, CML444, and YML46, were selected as female parents and crossed with the elite maize inbred line Ye107, which served as the common male parent, to develop a multi-parent population comprising four F8 recombinant inbred line (RIL) subpopulations. Using 6616 high-quality single nucleotide polymorphism (SNP) markers, we conducted genome-wide association analysis (GWAS) and genomic selection (GS) on 642 F8 RILs in four subpopulations across three different environments. Through GWAS, we identified 16 SNPs that were significantly associated with TW, encompassing two stable loci expressed across multiple environments. Furthermore, within the candidate regions of these SNPs, we discovered four novel candidate genes related to TW, namely Zm00001d044362, Zm00001d011048, Zm00001d011049, and Zm00001d031173 distributed on chromosomes 1, 3, and 8, which have not been previously reported. These genes are involved in processes such as signal transduction, growth and development, protein splicing, and pollen development, all of which play crucial roles in
inflorescence meristem development, directly affecting TW. The co-localized SNP, S8_137379725, on chromosome 8 was situated within a 16.569 kb long terminal repeat retrotransposon (LTR-RT), located 22.819 kb upstream and 26.428 kb downstream of the candidate genes (Zm00001d011048 and Zm00001d011049). When comparing three distinct GS models, the BayesB model demonstrated the highest accuracy in predicting TW. This
study establishes the theoretical foundation for future research into the genetic mechanisms underlying maize TW and the efficient breeding of high-yielding varieties with desired tassel weight through GS.