Nighttime warming increases winter-sown wheat yield across major Chinese cropping regions

Understanding the actual impacts of climatic warming on winter-sown wheat production will benefit cultivar breeding efforts and agronomic innovations and may help to improve food security. Therefore, we conducted a comprehensive study across the main Chinese winter wheat cropping regions, comprising field warming experiments at four locations and an analysis of 36 years of winter wheat yield data. In the field warming experiments, an increase of 1.0 °C in nighttime temperature enhanced wheat yield by 10.1% on average (P < 0.05). Warming-induced enhancement of 1000-grain weight explained most of these yield increases. Warming shortened the length of pre-flowering phase by 5.4 days, while it prolonged the length of post-flowering phase by 3.8 days. Grain yield increases with warming were similar across experimental sites, even though warming-induced changes in the length of growth periods decreased with increasing ambient temperature. Our analysis of the historical data set was consistent with our field warming experiments; between 1980 and 2015, the major Chinese cropping regions experienced significant warming, especially in daily minimum temperature. Across the historical data set, daily minimum temperature was positively correlated with wheat yield (142.0 kg ha−1 °C −1). Our findings are inconsistent with previous reports of yield decreases with warming and may help to inform policy decisions and agronomic innovations of Chinese wheat production to better cope with future climate warming.