Spring wheat (Triticum aestivum L.) yields across the Canadian prairies are rising, however, a yield gap remains between average yield and yield potential, which can be explored further under Prairie conditions. The high rates of nitrogen (N) fertilizer required for current high-yielding cultivars may increase lodging risk adding to this yield gap. The objectives of this study were to determine the influence of intensive management through N fertilization and plant growth regulator (PGR) application, on grain yield, yield components, and their relationships, in addition to lodging risk. Field trials were conducted at two locations in 2018 and 2019 in Manitoba, Canada, to evaluate three high-yielding spring wheat cultivars, three N management strategies, and the application of a PGR. Kernels per spike had the strongest overall linear relationship with grain yield (r² = .47), while the response of spikes per plant was highly related to yield response with alterations in N and PGR management practices (r² = .98). Splitting N fertilizer applications showed potential to reduce lodging risk of spring wheat, while maintaining yield and increasing protein. The PGR applications reduced lodging and increased grain yield by 91 kg ha⁻¹ mainly through increases in kernels per spike. To achieve consistent yield increases, management practices should maximize early season N availability to target increases in spikes per plant and kernels per spike, thus a PGR application may be required to balance increased lodging risk.

中文翻译：

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最大化加拿大东部大草原的春小麦生产力：I. 产量、产量构成和倒伏风险

春小麦（Triticum aestivumL.) 加拿大大草原的单产正在上升，但是，平均单产和单产潜力之间仍然存在单产差距，可以在大草原条件下进一步探索。当前高产品种所需的高氮 (N) 肥料用量可能会增加倒伏风险，从而加剧这种产量差距。本研究的目的是确定通过施氮肥和植物生长调节剂 (PGR) 应用的集约化管理对谷物产量、产量成分及其关系以及倒伏风险的影响。2018 年和 2019 年在加拿大马尼托巴省的两个地点进行了田间试验，以评估三个高产春小麦品种、三种氮管理策略和植物遗传资源的应用。每穗粒数与籽粒产量具有最强的整体线性关系（r ²  = .47)，而每株植物的穗状花序响应与 N 和 PGR 管理实践改变的产量响应高度相关 ( r ²  = .98)。分次施用氮肥显示出降低春小麦倒伏风险的潜力，同时保持产量和增加蛋白质。PGR 应用主要通过增加每穗粒数减少倒伏并增加谷物产量 91 kg ha ^{-1 。}为了实现一致的产量增长，管理实践应最大限度地提高季节早期氮的可用性，以增加每株植物的穗数和每穗的籽粒，因此可能需要 PGR 应用来平衡增加的倒伏风险。