Investigations of critical physiological traits associated with the genetic yield gain in wheat (Triticum aestivum) are essential to determine future crop breeding and management strategies. This study grew 32 cultivars released from 1965 to 2017 for two cropping seasons (a dry year, 2016–2017, and a humid year, 2017–2018) to examine yield potential achieved through efficiencies in canopy light interception, solar energy conversion, harvest index (HI), and nitrogen (N) uptake and utilization. Yield gain for wheat (25.0 ± 1.8 kg ha⁻¹ yr⁻¹) resulted from increases in plant biomass, HI, and N utilization efficiency (NUtE). Modern cultivars with an erect canopy and slender flag-leaves optimized light interception and could achieve higher biomass yield. The introduction of semi-dwarf genes (Rht-8) reduced plant height (0.05 yr⁻¹) and improved HI (0.004 yr⁻¹) and NUtE resulting from both increased pre-anthesis accumulated biomass and plant dry matter mobilization after anthesis. Greater biomass partitioning to spikes resulted in higher fruiting efficiency and grain number. Due to greater tillering capability through increased N uptake efficiency, increased fertile spikes and grain yield were observed. Among these newer cultivars, the rate of yield gain was slow, and yield stability was more affected by accumulative rainfall than diurnal temperature. The future challenge of wheat breeding is to maintain the genetic yield gain without increasing the reliance on chemical fertilizers under an increasingly variable climate.

中文翻译：

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1965年以来西南旱地冬小麦粮食产量辐射及氮素利用效率遗传进展：进展及改进展望

研究与小麦 ( Triticum aestivum )遗传产量增加相关的关键生理性状对于确定未来的作物育种和管理策略至关重要。该研究种植了 1965 年至 2017 年发布的 32 个栽培品种，用于两个作物季节（干旱年份，2016-2017 年和潮湿年份，2017-2018 年），以检查通过树冠遮光、太阳能转换、收获指数的效率实现的产量潜力(HI) 和氮 (N) 的吸收和利用。小麦增产 (25.0 ± 1.8 kg ha ^-1  yr ^-1) 是由于植物生物量、HI 和氮利用效率 (NUtE) 的增加所致。具有直立树冠和细长旗叶的现代栽培品种优化了光拦截并可以获得更高的生物量产量。半矮化基因 ( Rht-8 )的引入降低了株高 (0.05 yr ^-1 ) 并提高了 HI (0.004 yr ^-1) 和 NUtE 是由开花前积累的生物量和开花后植物干物质动员的增加引起的。更多的生物量分配到穗状花序导致更高的结果效率和谷物数量。由于通过提高 N 吸收效率提高分蘖能力，观察到可育穗和谷物产量增加。在这些新品种中，产量增长速度较慢，产量稳定性受累积降雨的影响大于昼夜温度。小麦育种的未来挑战是在气候变化越来越多的情况下，在不增加对化肥的依赖的情况下保持遗传产量的增加。