Abstract: Based on the data of precipitation,soil moisture and field investigation from 1990 to 2005 in Zhumadian City,Henan Province,the filling process and changes of filling velocity of winter wheat were analyzed in three chosen typical drought years,such as drought during the early filling stage,drought during the late filling stage and drought during the whole filling stage.The results showed that drought not only had obviously influenced on wheat filling velocity,but also shortened the wheat filling duration compared with normal years.The drought during the early filling stage accelerated wheat filling velocity and increased wheat grain weight,while the drought during the late filling stage restrained the wheat filling process.The drought during the whole filling stage significantly trailed off the filling velocity.

Key words: Winter wheat, Winter wheat, Drought, Filling, Filling velocity