Does temporary heat stress or low temperature stress similarly affect yield, starch, and protein of winter wheat grain during grain filling?

Temperature plays a critical role in wheat grain development. A controlled phytotron glasshouse study was done to investigate the effects of short-term low or high temperature stress on grain yield and the proportions of starch and protein in two wheat cultivars Ningmai 13 and Zhenmai 12. The duration of grain filling was longer under low temperature stress and was shorter under high temperature stress during various stages of grain filling. Grain filling rate, grain width, grain yield, contents of total starch and amylopectin of both cultivars were decreased by low or high temperature stress. However, the proportions of total protein, gliadin, and glutenin were increased dramatically after abnormal temperature stress. The significant increase in the proportion of protein was mainly caused by higher proportions of ω-gliadin and HMW-GS. For both cultivars, the formation of starch, protein, and grain yield was most sensitive to temperature stress during 15–17 days post anthesis (DPA), followed by 7–9 DPA for grain starch and yield formation, and 23–25 DPA for grain protein formation, respectively. Our study suggested that both high and low temperature stress after anthesis affected winter wheat grain yield, starch and protein accumulation, especially during the period of 15–17 DPA. [Display omitted] •Low or high temperature stress decreased wheat grain width and grain-filling rate, resulting in a huge yield loss.•The abnormal temperature decreased the starch content, while dramatically increased ω-gliadin and HMW-GS in grains.•The most sensitive stage of wheat yield and grain main components to short-term temperature stress was 15–17 DPA.