Photosynthesis and Dry Matter Production of Summer Corn under High Yield Condition in Guanzhong of Shaanxi Province

Based on the result of high-yielding maize hybrids,three summer maize hybrids(Xianyu 335,Zhengdan 958 and Shaandan 8806) were conducted to dry matter partitioning and photosynthetic characteristics of leaves in order to evaluate yield formation of three high-yielding maize hybrids during grain filling period.The results showed that yields of three summer maize hybrids were over 8 000 kg/hm2.Characteristic of grain filling analyzed by Richards equation showed three summer maize hybrids had the higher grain-filling rate,the longer active growing period,and it reached the maximum grain-filling rate,which indicated grain-filling traits was favorable to high yield in the experiment.Three summer maize hybrids had high net photosynthetic rate after anthesis,and the leaf area index(LAI) and decreased slowly from 20 d and 30 d after flowering,respectively.To obtain 8 000 kg/hm2 its need to maintain the leaves photosynthetic physiology quantity to maintain high grain-filling rate and long active growing period after anthesis,enhance the contribution after anthesis assimilates to grains.which may be one of the important roles in getting high-yield.