National Engineering and Technology Center for Information Agriculture, Jiangsu Key Laboratory for Information Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China.
Glob Chang Biol. 2014 Feb;20(2):372-81. doi: 10.1111/gcb.12442. Epub 2013 Nov 20.
Wheat is sensitive to high temperatures, but the spatial and temporal variability of high temperature and its impact on yield are often not known. An analysis of historical climate and yield data was undertaken to characterize the spatial and temporal variability of heat stress between heading and maturity and its impact on wheat grain yield in China. Several heat stress indices were developed to quantify heat intensity, frequency, and duration between heading and maturity based on measured maximum temperature records of the last 50 years from 166 stations in the main wheat-growing region of China. Surprisingly, heat stress between heading and maturity was more severe in the generally cooler northern wheat-growing regions than the generally warmer southern regions of China, because of the delayed time of heading with low temperatures during the earlier growing season and the exposure of the post-heading phase into the warmer part of the year. Heat stress between heading and maturity has increased in the last decades in most of the main winter wheat production areas of China, but the rate was higher in the south than in the north. The correlation between measured grain yields and post-heading heat stress and average temperature were statistically significant in the entire wheat-producing region, and explained about 29% of the observed spatial and temporal yield variability. A heat stress index considering the duration and intensity of heat between heading and maturity was required to describe the correlation of heat stress and yield variability. Because heat stress is a major cause of yield loss and the number of heat events is projected to increase in the future, quantifying the future impact of heat stress on wheat production and developing appropriate adaptation and mitigation strategies are critical for developing food security policies in China and elsewhere.
小麦对高温敏感，但高温的时空变化及其对产量的影响往往不为人知。本研究通过分析历史气候和产量数据，旨在描述中国小麦抽穗至成熟期间热胁迫的时空变化及其对小麦籽粒产量的影响。基于中国主要小麦种植区 166 个站点过去 50 年的实测最高温度记录，开发了几种热胁迫指数来量化抽穗至成熟期间的热强度、频率和持续时间。令人惊讶的是，由于低温导致的抽穗时间延迟和抽穗后阶段暴露在更温暖的年份中，一般较凉爽的北方小麦种植区比中国一般较温暖的南方小麦种植区的抽穗至成熟期间热胁迫更为严重。在过去几十年里，中国大部分主要冬小麦产区的抽穗至成熟期间热胁迫呈增加趋势，但南部地区的增加速度高于北部地区。在中国整个小麦种植区，实测籽粒产量与抽穗后热胁迫和平均温度之间存在显著的相关性，解释了约 29%的观测到的产量时空变异性。需要考虑抽穗至成熟期间热胁迫的持续时间和强度的热胁迫指数来描述热胁迫与产量变异性的相关性。由于热胁迫是导致产量损失的主要原因，并且未来预计热事件的数量将会增加，因此量化未来热胁迫对小麦生产的影响并制定适当的适应和缓解策略对于制定中国和其他地区的粮食安全政策至关重要。
