Abstract The effect of climate change is being observed in India in the form of shorter winter coupled with commencement of summer quite earlier than normal. The proximity of equator and late sowing of wheat (due to late harvesting of rice) exposes the wheat crop (Triticum aestivum L.) to high temperature stress during grain filling stage leading to terminal heat stress in the crop and reduced yield. There are limited studies done till date in India to assess the long term impact of climate variability on wheat yield and to develop adaptation strategies to reduce its negative impact. Therefore, in this study, simulation model (InfoCrop) and field experiment was used to assess the impacts of terminal heat stress on growth and yield of wheat as well as to identify adaptation strategies. Simulated results showed that terminal heat stress will reduce wheat yield by 18.1%, 16.1% and 11.1%, respectively in present, 2020 and 2050 scenarios. Advancement in sowing date, application of additional dose of nitrogen and irrigation at grain filling stage were found suitable options for preventing yield loss. Among various combinations of adaptation options, early sowing by 10 days from recommended sowing date with 30 kg ha−1 additional nitrogen fertilizer and one additional irrigation at grain filling stage was found most suitable. Adaptation of these strategies will help in reducing impact of heat stress by 7.5, 6.4 and 9% respectively in present, 2020 and 2050 heat stressed scenarios.

中文翻译：

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终末热应激对印度小麦产量的影响和适应选择

摘要 印度正在观察到气候变化的影响，即冬季较短，夏季开始比正常情况早得多。靠近赤道且小麦播种晚（由于水稻收割晚）使小麦作物（Triticum aestivum L.）在籽粒灌浆期面临高温胁迫，导致作物出现终末热胁迫并降低产量。迄今为止，在印度进行的评估气候变异对小麦产量的长期影响和制定适应战略以减少其负面影响的研究有限。因此，在本研究中，利用模拟模型（InfoCrop）和田间试验来评估末期热应激对小麦生长和产量的影响，并确定适应策略。模拟结果表明，在目前、2020 年和 2050 年的情景中，末期热应激将使小麦产量分别减少 18.1%、16.1% 和 11.1%。提高播种期、施氮肥和灌浆期灌溉是防止产量损失的合适选择。在各种适应方案组合中，发现从推荐播种日期起提前 10 天播种，并添加 30 kg ha-1 氮肥和在灌浆期额外灌溉 1 次是最合适的。在目前、2020 年和 2050 年的热应激情景中，这些策略的适应将有助于将热应激的影响分别降低 7.5%、6.4% 和 9%。发现在灌浆期增施氮肥和灌溉是防止产量损失的合适选择。在各种适应方案组合中，发现从推荐播种日期起提前 10 天播种，并添加 30 kg ha-1 氮肥和在灌浆期额外灌溉 1 次是最合适的。在目前、2020 年和 2050 年的热应激情景中，这些策略的适应将有助于将热应激的影响分别降低 7.5%、6.4% 和 9%。发现在灌浆期增施氮肥和灌溉是防止产量损失的合适选择。在各种适应方案组合中，发现从推荐播种日期起提前 10 天播种，并添加 30 kg ha-1 氮肥和在灌浆期额外灌溉 1 次是最合适的。在目前、2020 年和 2050 年的热应激情景中，这些策略的调整将有助于将热应激的影响分别降低 7.5%、6.4% 和 9%。