Abstract: Six sowing periods were set for La2577 and Nongmai No.4 to study the reproductive process, agronomic characters, grain yield and drought resistance of difterent early-maturing spring wheat varieties in Hulun Buir area. The results showed that the grain yield of La2577 and Nongmai No.4, sowed on May 30, were the highest, which were 5 393.55 and 5 353.65 kg/hm^2 respectively. Difterent sowing periods had a great impact on the growth and development of early maturity wheat varieties for further analysis, with the retardation of sowing period, wheat growth period was extended, and the agronomic characters such as plant height, panicle number, 1 000-grain weight, ear number per unit area and bulk density- were improved to varying degrees, and the drought resistance and disease resistance of wheat were enhanced to difterent degrees. In conclusion, moderate late sowing of early maturity varieties can avoid drought in early spring and meeting rain to grow, prolong the growth period, maintain high panicle number, ear number per unit area and 1000-grain weight and other yield components, so as to ensure high grain yield.

Key words: Sowing date , Wheat , Grain yield , Agronomic traits