Abstract: Researches on the relationship between photosynthesis and wheat yield have attracted the attention of both domestic and overseas scholars. There is no report about the study on the effects of exogenous chromosomes on photosynthesis using the substitution series as materials. In this research, Triticum aestivum cv. Chinese Spring- Lophopyrum elongatum (Host) A.L?ve disomic substitutions series were used as materials and flag leaves as the measuring position. And the CI-310 Portable Photosynthesis System made by CID Co. in USA was used to measure the net rate of photosynthesis of flag leaves in different developing stages and the correlations between photosynthesis and yield. The result showed that the line of DS2Ee (2A) has the highest photosynthetic rate in the whole developing stage when it is in the anthesis, it can be used in improving process of the character of kernel number. The flag leaves of DS4Ee (4A, 4B, 4D) lines can remain certain high net photosynthetic rate from heading to grain filling stage. It can be used in research of promoting the yield index like 1000-grain weight through improving the photosynthetic rate at grain filling stage.

Key words: Wheat, Lophopyrum elongtum, substitution, photosynthesis, gene location