Abstract: Three different population densities of summer sowing foxtail millet(Lugu 10)were studied in two years. The results indicated that the changes of canopy photosynthesis rates(CPR)showed single peak curves,the peak of CPR was in flowering stage, the CPR from boot stage to the beginning of seed filling stage all kept high photosynthesis rate, but the CPR after flowering stage decreased very quickly in the condition of high density. The CPR contribution of different layers to organs total CPR were studied in the flowering and late seed-filling stages.The results showed that the CPR contribution of upper three leaves was the biggest,that of middle three leaves was the second,that of lower leaves was smaller, the contribution of stems and sheathes only accounted to 5% or so, the ears expressed respiration consuming, the proportion of consuming total CPR was tended to increase. Based on the research results, the criteria of photosynthesis were raised for the yield over 400 kg/mu of Lugu 10:CPR at the flowering stage should be over 31 µmol·m^-2·s^-1 and should keep in higher level from then,CPR at mature stage should keep 12µmol·m^-2·s^-1.The relationship between CPR and yield components also were discussed.

Key words: Foxtail millet(Setaria italica Beauv.), Canopy photosynthesis rate(CPR), Density, Organ, Contribution of photosynthesis

CLC Number: 

• S515.01