Under field conditions

changes of grain filling and yield of winter wheat with large-ear cultivar Yumai66 were studied in Zhengzhou experimental sit in Henan province during the 200~2002 growing seasons

there was different significantly between 2000~2001 and 2001~2002.The grain filling process of Yumai66

were modeled with Cubic

Quadratic and Logistic equation

R~2 values of modeled equations were significant

and the Cubic R~2 value was the significantest.There was a significant correlation between W and Ws

Se

S in dry year of 2000~2001

and between W and Ws

V

Vs

Vmax in rainy year of 2001~2002.In comparison with 2001~2002

grain filling duration was shortened

filling rate was smaller

which resulted in falling of grain weight in 2000~2001.Effects of irrigation on filling parameters were different between two year-styles

with irrigation improving

S and Se was lagged

filling rate reduced in 2000~2001

but S and Se was shortened

grain filling rate of irrigation treatment with one application was lowest

that of irrigation treatment with two applications was the highest in 2001~2002.Irrigation improved yield significantly in 2000~2001

but there was not significant different between treatments

even yield of irrigation treatment with three applications was lower than that of irrigation treatment with two applications in 2001~2002.