Effects of spring low-temperature stress on winter wheat seed-setting characteristics of spike

Global climate change leads to frequent occurrence of low-temperature stress (LTS), which poses a serious threat to global food security. Here, environment-control phytotron experiments were conducted on cold-responsive cv. XM26 and cold-tolerant cv. YN19 during the anther differentiation period. Six LTS levels (4, 2, 0, -2, -4, -6 degrees C) and a control treatment (10 degrees C) were set to study the effects of different levels of LTS on wheat seed-setting characteristics and yield. LTS significantly decreased grain number per spike, 1 000-grain weight, and grain yield per plant (GYPP) of the two wheat cultivars. Each spike's grain number and weight distribution showed a quadratic curve, and the near-medium dominance of grain development was not affected by temperature. The grain number percentage and grain weight of wheat at different grain positions were G2 (2nd grain position) >= G1 (1st grain position) > G3 (3rd grain position) > G4 (4th grain position), in which G3 and G4 grain positions were more sensitive to LTS. In summary, LTS during the anther differentiation in wheat mainly led to a decrease in GYPP by significantly reducing the number and weight of inferior grains. Improving wheat cultivation measures and promoting the development of inferior grains are significant ways to prevent disasters and increase wheat quality and productivity in the future.