Abstract: 【Objective】 In order to study the effect factors of photosynthetic rate in male sterility lines of wheat, male sterile lines of CHA (chemical hybridizing agent) and cytoplasmic K (Aegilops kotschyi), T (Triticum timopheevi), V (Aegilops ventricosa) types of male sterile wheat were compared with their maintainer lines in the dynamic changes of net photosynthetic rate (Pn) and relatively physiologic and environmental factors, which relationship between them were also analyzed. 【Method】 At 4 different developmental stages, CIRAS-Ⅰ was used to record data of flag leaf, including Pn and stomatal conductance (Gs), transpiration rate (Tr), water use efficiency (WUE), photon flux density (PFD), intercellular CO2 concentration (Ci), atmospheric CO2 concentration (Ca), leaf temperature (Ti), atmospheric temperature (Ta), stomatal limiting value (Ls). The data was analyzed by statistical analysis system in order to acquire the results of difference analysis, correlation analysis, path analysis and regression analysis. 【Result】 Pn and Gs, Tr had their most values at anthesis stage. The dynamic changes of Pn was positively correlated with Gs and Tr, and the correlation coefficients were 0.9305**－0.9677**, and 0.8081*－0.9068** respectively (r0.05=0.754, r0.01=0.874). Cytoplasms of K, T, V-type male sterile had negative effects on Pn, Gs and WUE of flag leaf with different extent. Tr of flag leaf depressed distinctly on account of CHA, but CHA had no significantly negative effects on the water use efficiency of wheat flag leaf. As to K, T, V, CHA-type malesterile wheat, the dynamic changes of Pn were the same with Gs and Ci, and were different from Ls, which indicated that the dynamic changes of Pn were restricted by the stomatal factor. Regression equation was significant (R2= 0.9658), which could preferably reflect the rules of dynamic changes of Pn and the other factors in K, T, V, CHA-type male sterile lines. 【Conclusion】 Gs was the uppermost direct effect factor on Pn of K, T, V, and CHA types. And their direct path coefficients between Pn and Gs were 0.4943－0.6774, which were all significant. Furthermore, Tr, PFD, and Ta had significant effect on Pn of K, T-type male sterile lines, so did PFD and Ca on Pn of V-type male sterile lines. Chemical hybridizing agent led that Gs and Ci restricted the raise of Pn in CHA-type male sterile lines, which reflected Gs and Ci were the uppermost effect factors on Pn of CHA types.

Key words: Wheat (Triticum aestivum L.), Male sterile lines, Photosynthetic rate, Effect factors