Abstract:

In order to clarify the risk changes of dry-hot wind in different sowing dates of different types of wheat under the current climate situation, taking Jimai 22 (semi-winter and partial-winter variety), Zhoumai 18 (semi-winter and partial-spring variety) and Xinong 529 (weak-spring variety) as materials to study the phenological period, yield and its compositions of wheat through three years experiments. Based on the analysis of the grain filling rule in two years and the distribution of dry-hot wind in 1987-2016, the probability of occurrence of dry-hot wind at 95% grain filling in different sowing dates was discussed. The results showed that postponing the sowing date could reduce tillering before winter but increase tillering number in spring. Delaying sowing date shortened the grain filling duration and accelerated the grain-filling rate, and the probability of dry-hot wind did not increase significantly within a certain sowing date range. Jimai 22 planted in the pre-winter accumulated temperature range of 380℃-680℃, Zhoumai 18 and Xinong 529 planted in the pre-winter accumulated temperature range of 250℃-680℃. The dry-hot wind risk remained the same, and it increased significantly as the accumulated temperature continued to decrease. Under the conditions of this experiment, the grain-filling rate increased and the risk of dry-hot wind did not significantly change when moderately postponing the sowing date, decreasing the accumulated temperature before winter, and increasing the sowing amount, so the wheat yield of different year types was stable. Under the current climate conditions, the optimum accumulated temperature before winter could decrease from about 600℃ to 380℃, and two to four tillers before winter, which is an effective way to stabilize wheat yield.

Key words: Wheat cultivars, Accumulated temperature before winter, Phenological stage, Grouting rate, Dry-hot wind risk, Yield