Maize (Zea mays L.) production in Argentina changed markedly during the last decade due to the widespread adoption of late sowing dates, expanding its productive area, and diversifying crop end-uses. This study was conducted to assess how the sowing date and nitrogen (N) availability affect grain yield, its physiological determinants (biomass and its partitioning), and numeric components (kernel number and kernel weight) of maize hybrids marketed for different end-uses. Field experiments were conducted in two growing seasons (2019–2020 and 2020–2021) and two sowing dates within each season (early and late) at a site in the main maize-producing region of Argentina. Within each season × sowing date combination, eight commercial maize hybrids (commercialized as grain, dual-purpose, or silage) were tested under two N levels (N0: no N applied; N250: fertilized with 250 kg N ha⁻¹). The greatest grain yield, biomass, kernel number, and harvest index corresponded to the grain hybrids. Dual-purpose hybrids showed an intermediate grain yield, the highest kernel weight, and a more “silage” than “graniferous” behavior. Silage hybrids had improved light interception up to silking + 15 days (R2) but exhibited the lowest grain yield. Differences in end-use steered crop breeding efforts toward different physiological strategies. The improved understanding of the physiological mechanisms underlying the productivity among maize hybrids with varying end-uses will assist in the selection and management of suitable cultivars to be grown under different systems and environmental variations associated with an extended sowing date period.

中文翻译：

---

具有不同最终用途的温带玉米杂交种的产量测定：生理生态分析


由于广泛采用晚播期、扩大生产面积和作物最终用途多样化，阿根廷的玉米 （Zea mays L.） 生产在过去十年中发生了显著变化。本研究旨在评估播种期和氮 （N） 有效性如何影响用于不同最终用途的玉米杂交种的产量、其生理决定因素（生物量及其分配）和数字成分（籽粒数和籽粒重量）。在阿根廷主要玉米产区的一个地点，在两个生长季节（2019-2020 年和 2020-2021 年）和每个季节的两个播种日期（早播和晚播日期）进行了田间试验。在播×日期组合的每个季节中，在两个氮水平下测试了 8 个商业玉米杂交种（商业化为谷物、两用或青贮饲料）（N0：不施用氮;N250：用 250 kg N ^ha-1 施肥）。最大的谷物产量、生物量、籽粒数和收获指数对应于谷物杂交种。两用杂交种显示出中等的谷物产量、最高的籽粒重量以及更“青贮”而不是“花岗岩”的行为。青贮杂交种在吐丝 + 15 天 （R2） 之前具有更好的光截留能力，但表现出最低的谷物产量。最终用途的差异将作物育种工作引导至不同的生理策略。对具有不同最终用途的玉米杂交种生产力的生理机制的更好理解将有助于选择和管理在不同系统和与延长播种期相关的环境变化下生长的合适品种。