Screening maize L.) cultivars for high grain yield while conserving nitrogen (N) fertilizer is of long-term strategic importance in addressing food security and environmental pollution issues. Limited knowledge exists regarding the differences in N efficiency of modern high-yielding cultivars and the agronomic traits that contribute most to grain yield. Revealing these physiological traits is crucial for understanding the limiting factors of grain yield potential in maize cultivars. A three-year (2018–2020) field experiment was conducted using 16 maize cultivars under low-N (LN) and high-N (HN) conditions. Low N stress reduced grain yield by 43% and yield components grain number per ear (GN), 100-grain weight (HKW) and number of ears per hectare (EN) by 22%, 12% and 13%, respectively. Analysis of the relationship between grain yield and agronomic traits has indicated a strong correlation with the accumulation of dry matter (DM) and N, most notably during the post-silking stage. The 16 cultivars were classified into four types according to the average yield of the test cultivars under the conditions of HN and LN as the dividing line. Under HN and LN conditions, the H0HN (efficient under both HN and LN conditions) cultivar type exhibited 21% and 60% higher grain yields compared to the L0LN (inefficient under both HN and LN conditions) cultivar type. The direct path coefficient linking GN to grain yield is 0.592, representing the primary contribution to the variance in grain yield. Under both HN and LN conditions, the H0HN cultivar type demonstrated a significant enhancement in post-silking dry matter accumulation, with increases of 30% and 64% over the L0LN cultivar type, respectively, while the N accumulation post-silking was elevated by 56% and 139%. The cultivars with H0HN and L0HN (efficient only under HN conditions) types had the potential to increase grain yield by 2.4%–6.1% and save 5.5%–15.7% of N fertilizer. Compared with L0LN cultivar type, H0HN cultivar type have higher N uptake efficiency and partial fertilizer productivity of N. In conclusion, the target traits for breeding modern N-efficient cultivars include higher post-silking DM accumulation and N accumulation. These traits play a positive role in increasing GN and the HKW, thereby fostering an increase in grain yield.

中文翻译：

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玉米吐丝后农艺性状的改善有助于氮高效品种的高产


筛选高产玉米品种，同时节约氮肥，对于解决粮食安全和环境污染问题具有长期战略意义。关于现代高产品种的氮效率差异以及对谷物产量贡献最大的农艺性状的知识有限。揭示这些生理特征对于了解玉米品种籽粒产量潜力的限制因素至关重要。使用 16 个玉米品种在低氮（LN）和高氮（HN）条件下进行了为期三年（2018-2020）的田间试验。低氮胁迫使谷物产量降低 43%，产量组成部分每穗粒数 (GN)、百粒重 (HKW) 和每公顷穗数 (EN) 分别降低 22%、12% 和 13%。对谷物产量和农艺性状之间关系的分析表明，与干物质（DM）和氮素的积累有很强的相关性，尤其是在吐丝后阶段。以HN和LN条件下供试品种的平均产量为分界线，将16个品种分为4个类型。在 HN 和 LN 条件下，与 L0LN（在 HN 和 LN 条件下均无效）品种类型相比，H0HN（在 HN 和 LN 条件下均有效）品种类型的籽粒产量分别高出 21% 和 60%。 GN与粮食产量的直接路径系数为0.592，代表对粮食产量方差的主要贡献。在 HN 和 LN 条件下，H0HN 品种的吐丝后干物质积累显着增强，分别比 L0LN 品种增加了 30% 和 64%，而吐丝后氮素积累则提高了 56%。 %和139%。 H0HN和L0HN（仅在HN条件下有效）类型的品种可提高粮食产量2.4%~6.1%，节省氮肥5.5%~15.7%。与L0LN品种相比，H0HN品种具有更高的氮素吸收效率和氮肥部分肥生产力。综上所述，选育现代高效氮肥品种的目标性状包括较高的吐丝后干物质积累和氮素积累。这些性状对于增加GN和HKW具有积极作用，从而促进粮食产量的增加。