Department of Agronomy, Kansas State University, 2004 Throckmorton Plant Science Center, Manhattan, KS 66506, USA.
Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, USA.
J Exp Bot. 2022 Jun 2;73(11):3597-3609. doi: 10.1093/jxb/erac103.
Over the past century of maize (Zea mays L.) breeding, grain yield progress has been the result of improvements in several other intrinsic physiological and morphological traits. In this study, we describe (i) the contribution of kernel weight (KW) to yield genetic gain across multiple agronomic settings and breeding programs, and (ii) the physiological bases for improvements in KW for US hybrids. A global-scale literature review concludes that rates of KW improvement in US hybrids were similar to those of other commercial breeding programs but extended over a longer period of time. There is room for a continued increase of kernel size in maize for most of the genetic materials analysed, but the trade-off between kernel number and KW poses a challenge for future yield progress. Through phenotypic characterization of Pioneer Hi-Bred ERA hybrids in the USA, we determine that improvements in KW have been predominantly related to an extended kernel-filling duration. Likewise, crop improvement has conferred on modern hybrids greater KW plasticity, expressed as a better ability to respond to changes in assimilate availability. Our analysis of past trends and current state of development helps to identify candidate targets for future improvements in maize.
在过去的一个世纪中，玉米（Zea mays L.）的培育取得了进展，这是几个内在生理和形态特征改进的结果。在这项研究中，我们描述了（i）在多个农业环境和育种计划中，粒重（KW）对产量遗传增益的贡献，以及（ii）美国杂交种 KW 改进的生理基础。对全球范围内文献的回顾得出的结论是，美国杂交种的 KW 改进速度与其他商业育种计划相似，但持续时间更长。对于大多数分析的遗传材料，玉米的籽粒大小仍有继续增加的空间，但籽粒数量和 KW 之间的权衡对未来的产量进展构成了挑战。通过在美国对先锋种业 ERA 杂交种的表型特征进行分析，我们确定 KW 的提高主要与延长的灌浆期有关。同样，作物改良赋予了现代杂交种更大的 KW 可塑性，表现为更好地响应可同化物质供应变化的能力。我们对过去趋势和当前发展状况的分析有助于确定未来提高玉米产量的候选目标。
