de Oliveira Silva Amanda, Slafer Gustavo A, Fritz Allan K, Lollato Romulo P
Department of Agronomy, Kansas State University, Manhattan, KS, United States.
Department of Crop and Forest Sciences, University of Lleida - AGROTECNIO Center, Lleida, Spain.
Front Plant Sci. 2020 Jan 10;10:1644. doi: 10.3389/fpls.2019.01644. eCollection 2019.
A great majority of dryland wheat producers are reluctant to intensify management due to the assumption that lack of water availability is the most critical factor limiting yield and thus, the response to management intensification would be limited. We conducted on-farm field experiments across three locations and two growing seasons in Kansas using 21 modern winter wheat genotypes grown under either standard (SM) or intensified management (IM) systems. The goals of this study were to (i) determine whether the SM adopted is adequate to reach achievable yields by farmers in the region and (ii) identify differences in responsiveness to IM among a range of modern genotypes. Across all sites-years and genotypes, the IM increased yield by 0.9 Mg ha, outyielding the SM system even in the lowest yielding conditions. As expected, the yield response to IM increased with the achievable yield of the environment and genotype. Across all sources of variation, the yield responsiveness to IM was related to increased biomass rather than harvest index, strongly driven by improvements in grain number (and independent of changes in grain weight), and by improvements in N uptake which resulted from greater biomass and shoot N concentration. The IM system generally also increased grain N concentration and decreased the grain N dilution effect from increased yield. Genotypes varied in their response to IM, with major response patterns resulting from the combination of response magnitude (large vs. small) and consistency (variable vs. consistent). Genotypes with high mean response and high variability in the response to IM across years could offer greater opportunities for producers to maximize yield as those genotypes showed greater yield gain from IM when conditions favored their response. For the background conditions evaluated, intensifying management could improve wheat yield in between c. 0.2 and 1.5 Mg ha depending on genotype.
绝大多数旱地小麦生产者不愿加强管理，因为他们认为缺水是限制产量的最关键因素，因此，加强管理的效果将很有限。我们在堪萨斯州的三个地点和两个生长季节开展了田间试验，使用21个现代冬小麦基因型，分别种植于标准管理（SM）或强化管理（IM）系统下。本研究的目的是：（i）确定所采用的标准管理是否足以让该地区的农民实现可达到的产量；（ii）找出一系列现代基因型对强化管理的反应差异。在所有地点-年份和基因型中，强化管理使产量提高了0.9 Mg/ha，即使在产量最低的条件下，其产量也高于标准管理系统。正如预期的那样，对强化管理的产量反应随着环境和基因型可达到的产量而增加。在所有变异来源中，对强化管理的产量反应与生物量增加有关，而非收获指数，主要是由粒数增加（与粒重变化无关）以及生物量和地上部氮浓度增加导致的氮吸收改善所驱动。强化管理系统通常还提高了籽粒氮浓度，并降低了因产量增加而产生的籽粒氮稀释效应。基因型对强化管理的反应各不相同，主要的反应模式是由反应幅度（大或小）和一致性（可变或一致）的组合导致的。多年来对强化管理平均反应高且反应变异性大的基因型，可为生产者提供更大的机会来实现产量最大化，因为在条件有利于其反应时，这些基因型从强化管理中获得的产量增益更大。在所评估的背景条件下，根据基因型不同，加强管理可使小麦产量提高约0.2至1.5 Mg/ha。
