Sowing date (SD) modifies the environmental conditions during the kernel-filling period as well as during kernel dry down after physiological maturity (PM), particularly for late-sown maize (Zea mays L.) crops that currently cover 50 % of the maize area in Argentina. The main goal of this work was to evaluate breeding effects on kernel filling and kernel desiccation traits in a set of five commercial maize hybrids released by a single breeding program between 1980 and 2016 when grown under contrasting environments in the temperate Central Pampas region. The evolution of kernel weight (KW) and kernel moisture (KM) were assessed. Maximum KW (KW_MAX), maximum kernel water content (KWC_MAX), kernel filling rate (KFR), kernel filling duration (KFD) and KM at silking+20 days (KM_R1+20) and PM (KM_PM) were computed together with husks number. Pre-PM kernel desiccation was described using an exponential decay model with k₁ as the proportionality drying coefficient. For the post-PM period, kernel desiccation was modelled assuming that the change in KM in a given period is proportional to the difference between the kernel and the equilibrium moisture contents, where k₂ was the corresponding proportionality drying coefficient. For KW_MAX, a genetic progress of 0.26 % year ⁻¹ (p < 0.05) was estimated from 1993 to 2016. This trend was explained by the increase registered in KFD (0.32 % year⁻¹, p < 0.01), which was partially compensated by a reduction in KFR (−0.08 % year⁻¹, p < 0.05). No genetic progress was detected for husks number, KWC_MAX, KM_R1+20, KM_PM, k₁ and k₂, but introduction of dent germplasm produced an increase in KWC_MAX, KM_R1+20 and KM_PM and a decrease in k₂. KFR and KFD as well as kernel desiccation dynamics were strongly affected by SDs. Breeding effects that extended KFD, together with the broad adoption of late sowings, promote a reduction in k₂, which must be considered for the correct assessment of trade-offs between drying costs and kernel quality penalization by pests and diseases.

播种日期 (SD) 改变了籽粒灌浆期以及生理成熟 (PM) 籽粒干枯期间的环境条件，特别是对于目前覆盖 50%玉米的晚播玉米 ( Zea mays L.) 作物阿根廷地区。这项工作的主要目标是评估 1980 年至 2016 年间在温带中部潘帕斯地区的对比环境下生长时，由单一育种计划发布的一组五个商业玉米杂交种对籽粒灌浆和籽粒干燥性状的育种影响。评估了籽粒重量 (KW) 和籽粒水分 (KM) 的演变。最大 KW (KW _MAX )、最大仁含水量 (KWC _MAX))、籽粒灌浆率 (KFR)、籽粒灌浆持续时间 (KFD) 和吐丝 +20 天的 KM (KM _R1+20 ) 和 PM (KM _PM ) 与壳数一起计算。使用以k ₁作为比例干燥系数的指数衰减模型来描述 PM 前内核干燥。对于 PM 后时期，假设给定时期 KM 的变化与谷粒和平衡水分含量之间的差异成正比，其中k ₂是相应的比例干燥系数，则对谷粒干燥进行建模。对于 KW _MAX， 0.26 % 年^-1的遗传进展(p < 0.05) 是从 1993 年到 2016 年估计的。这一趋势的解释是 KFD 记录的增加（0.32 % 年^-1，p < 0.01），这部分被 KFR 的减少（-0.08 % 年^-1 , p < 0.05)。稻壳数、KWC _MAX、KM _R1+20、KM _PM、k ₁和k ₂未检测到遗传进展，但马齿种质的引入使KWC _MAX、KM _R1+20和KM _PM增加，k降低₂. KFR 和 KFD 以及内核干燥动力学受到 SD 的强烈影响。延长 KFD 的育种效应，以及广泛采用晚播，促进了k ₂的降低，必须考虑到正确评估干燥成本和病虫害对籽粒质量的影响之间的权衡。