Effects of Post-Anthesis Temperature and Radiation on Grain Filling and Protein Quality of Wheat (Triticum aestivum L.)

Due to climate change, global warming, and reduced radiation, there is an urgent need for research to explore the effects on wheat grain filling and protein-related quality. In this study, two spring and two semi-winter varieties were analyzed. Six sowing dates were set in the experiment, at 10-day intervals from the beginning of the local sowing window. The seedling population of the first sowing date (S1) was 300 × 104 plants ha−1, which was observed to have increased by about 10% by the subsequent sowing date. During the experiment, due to the different dates of sowing, the treatments were in different growth stages; so, all the treatments were grown under different day and night temperatures and radiation to study the effects on post-anthesis grain filling and protein quality. The results showed that the sowing date decreased the effective accumulated temperature (EAT) and the cumulative radiation after anthesis and increased the daily average, maximum, and minimum temperatures. The decrease in the EAT of 94.99 °C d and the increase in the daily average temperature of 1.59 °C after antrum resulted in a decrease in the wheat grain weight of 4.5 g and an increase in the grain filling rate of 0.029 mg d−1. This may be due to the shortening of the wheat filling time with the increase in the day/night temperatures. Compared with the normal sowing date, the later sowing date caused a decrease in the EAT and an increase in the Tmean, which led to an increase in the wheat protein content, wet gluten content, and sedimentation value. There was a positive correlation between the grain filling rate and the protein content in the wheat. Compared with radiation, temperature significantly regulates wheat grain filling and protein formation. These results can be used to guide the sowing date to obtain a higher quality of wheat protein in the future climate change.