Low grain moisture at harvest is crucial for safe production, transport and storage, but the genetic architecture of this trait in maize (Zea mays) remains elusive. Here, we measured the dynamic changes in grain moisture content in an association-mapping panel of 513 diverse maize inbred lines at five successive stages across five geographical environments. Genome-wide association study (GWAS) revealed 71 quantitative trait loci (QTLs) that influence grain moisture in maize. Epistatic effects play vital roles in the variability in moisture levels, even outperforming main-effect QTLs during the early dry-down stages. Distinct QTL–environment interactions influence the spatio-temporal variability of maize grain moisture, which is primarily triggered at specific times. By combining genetic population analysis, transcriptomic profiling and gene editing, we identified GRMZM5G805627 and GRMZM2G137211 as candidate genes underlying major QTLs for grain moisture in maize. Our results provide insights into the genetic architecture of dynamic changes in grain moisture, which should facilitate maize breeding.

中文翻译：

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玉米籽粒水分动态变化的遗传结构

收获时的低谷物水分对于安全生产、运输和储存至关重要，但这种性状在玉米中的遗传结构（Zea mays) 仍然难以捉摸。在这里，我们在五个地理环境的五个连续阶段测量了 513 个不同玉米自交系的关联绘图面板中谷物水分含量的动态变化。全基因组关联研究 (GWAS) 揭示了 71 个影响玉米籽粒水分的数量性状位点 (QTL)。上位效应在水分含量的变化中起着至关重要的作用，甚至在早期干燥阶段的表现优于主效应 QTL。不同的 QTL-环境相互作用影响玉米籽粒水分的时空变异，这主要在特定时间触发。通过结合遗传群体分析、转录组分析和基因编辑，我们确定了GRMZM5G805627和GRMZM2G137211作为玉米籽粒水分主要 QTL 的候选基因。我们的结果提供了对谷物水分动态变化的遗传结构的见解，这将促进玉米育种。