Abstract Frequent waterlogging events have severely constrained wheat production in the middle and lower reaches of the Yangtze River, China (YR). Understanding the effects of waterlogging on agronomic traits and grain yield in historic wheat cultivars can help establish strategies for stable- and high-yield breeding programs. We conducted a two-year field experiment using 10 winter wheat cultivars that were released and widely planted in YR from 1967 to 2010. Ten days of waterlogging were imposed on plants beginning at stem elongation (Zadoks growth stage, GS33). Grain yield was improved with the year of cultivar release, gaining 53 kg ha−1 yr−1 (0.6% yr−1) under normal watering condition and 35 kg ha−1 yr−1 (0.51% yr-1) under waterlogging treatment from 1967 to 2010, showing that waterlogging tolerance declined with cultivar improvement. Yield improvement was primarily due to the synergistic development of kernels per spike and 1000-kernel weight, as well as the increased harvest index from the 1960s to 1990s and the increased total biomass from the 1990s to 2000s. Furthermore, genetic improvement significantly increased post-anthesis biomass, leaf area at milk-ripe (GS75), and net photosynthetic rate in flag leaf. Due to waterlogging, kernels per spike, sing-spike yield, total biomass, post-anthesis biomass, leaf area at milk-ripe decreased more with the year of cultivar release, but we did not find a significant reduction in spikes per m2, 1000-kernel weight, and harvest index across cultivars. Grain yield and single-spike yield were significantly and positively correlated with leaf area at milk-ripe, as well as net photosynthetic rate in flag leaf. However, their reductions were only significantly correlated with the reduction in leaf area. Moreover, waterlogging did not significantly affect flag leaf area. This study suggests that improving the photosynthetic capacity of flag leaf will assist in the selection of new wheat varieties with waterlogging-tolerance and high-yields. Further studies are required to investigate the responses of wheat canopy architecture and photosynthesis to waterlogging and their functions for crop yield.

中文翻译：

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涝渍对长江中下游历史小麦品种产量及相关性状的影响

摘要 频繁的内涝严重制约了长江中下游地区的小麦生产。了解涝渍对历史悠久的小麦品种的农艺性状和谷物产量的影响有助于制定稳定和高产育种计划的策略。我们使用从 1967 年到 2010 年在 YR 释放和广泛种植的 10 个冬小麦品种进行了为期两年的田间试验。对从茎伸长（Zadoks 生长阶段，GS33）开始的植物强加 10 天的涝渍。粮食产量随品种放行年份增加，正常浇水条件下增产53 kg ha-1 yr-1（0.6% yr-1），涝渍处理增产35 kg ha-1 yr-1（0.51% yr-1）从1967年到2010年，表明随着品种改良，耐涝性下降。产量的提高主要是由于每穗粒数和千粒重的协同发展，以及 1960 年代至 1990 年代收获指数的增加和 1990 年代至 2000 年代总生物量的增加。此外，遗传改良显着增加了花后生物量、乳熟叶面积 (GS75) 和旗叶的净光合速率。由于涝渍，每穗粒数、单穗产量、总生物量、花后生物量、乳熟叶面积随着品种释放年份的增加而减少更多，但我们没有发现每平方米穗数的显着减少，1000 - 不同品种的籽粒重量和收获指数。籽粒产量和单穗产量与乳熟叶面积和旗叶净光合速率呈显着正相关。然而，它们的减少仅与叶面积的减少显着相关。此外，涝渍对旗叶面积没有显着影响。本研究表明，提高旗叶光合能力将有助于筛选耐涝高产小麦新品种。需要进一步研究小麦冠层结构和光合作用对涝渍的响应及其对作物产量的影响。