Effects of Continuous Drought on Photosynthesis and 1000-grain Weight of Wheat Cultivated in Filed

[Objective] The research aimed to investigate the effects of continuous drought stress on photosynthesis and 1000-grain weight of 9 wheat combinations.[Method] Nine wheat lines under nature field drought stress were used to study the change tendency of chlorophyll,photosynthesis(Pn),flag leaf area,1 000-grain weight during grain filling period.The relationship between chlorophyll content,photosynthesis parameters and grain weights was analyzed by using correlation,gray correlation analysis.[Result] During the field drought stress,the chlorophyll content decreased greatly in drought first stage,the decreasing ratio of chlorophyll content was slowed at the continued stages,which suggested the adaptation to drought;Pn showed the decreasing tendency at the first and second stages,but some lines showed increasing tendency.The main parameters affecting the Pn were gm,E,and WUE;The main factors affecting the 1000-gain weight were chlorophyll content,the flag leaf area and Pn of later drought stages.[Conclusion] The wheat had the adaptability to drought stress under nature field drought stress.