Abstract: In field experiment，the effect of five irrigation treatments on the change of flag leaf photosynthetic parameters ，water use efficiency and grain yield in kernel filling stage of dry land winter wheat is studied with Qingmai 6. Net photosynthetic rate (Pn) ，stomatal conductance (Gs) ，intercellular CO2 concentration (Ci) and transpiration rate (Tr) in flag leaves of super-high yielding winter wheat were measured in an open-circuit gas channel system，moreover，Pn of winter wheat flag leaf is simulated in nonrectangular hyperbolic model and the characteristic parameter of light response is obtained. The results showed that Pn，Gs and Tr were on the rise with the twice supplementing irrigations and less twice supplementing irrigations，the highest one of which was treatment W3(Jointing 60 mm + Filling 60 mm) ，but Ci and water use efficiency(WUE) had decreasing tendency with supplementing irrigation; But Pn and Gs of treatment W4(Jointing 60 mm + Booting 60 mm + Filling 60 mm) were less than that less twice supplementing irrigations，Ci，Tr were higher than that else treatments obviously，and WUE is the least all of treatments， which indicated that over supplementing irrigation has negative influence on photosynthesis of flag leaves in dry-land winter wheat at filling stage. The grain yield of the treatment W3 is the highest ，but there were no significant difference among the other four treatments except the CK. Considering the grain yield，water use efficiency and other factors， the treatment W1(jointing irrigation irrigation 60 mm) is the best supplementing irrigation model in dry land winter wheat and high-yield cultivation.

Key words: Limited irrigation, Dry-land wheat, Light-response, Yield

CLC Number: 

• Q152.01