Abstract: Identifying the relationship between the leaf area index (LAI) and grain filling in different growth stages of new maize hybrids under different planting densities and to reveal the regulation mechanism of different density on population LAI and grain filling characteristics.In this study,3 high-yield hybrids in the Middle and South Area of Hebei Province were used as experimental materials,the effects of 6 planting densities on LAI and grain filling characteristics in different growth stages were studied.The results indicated that 3 hybrids of LAI were first increased and then decreased in the whole growth period,reached its peak in the silking stage,then decreased gradually post-silk. The LAI with each stage of 3 varieties were increased with the density increasing,the LAI of Hengyu 1182 groups was higher than Zhengdan 958 and Xianyu 335 under the same planting density,the density tolerance showed strong. The LAI and grain yield showed a quadratic function,and the optimum LAI of Zhengdan 958,Xianyu 335 and Hengyu 1182 were,3.252,3.193 and 4.125 respectively.3 varieties of silking stage maximum LAI and planting density were significantly related,while maximum LAI increased linearly with the increased of density. The 100-kernel weight of 3 varieties showed a slow-fast-slow "S" shape change with the filling process,and the grain filling rate of varieties showed a single peak parabolic curve in the whole growth process,the maximum grain filling rate appeared at 30 d after pollination,the maximum grain filling rate of different varieties with different treatments showed that low density > medium density > high density,and the grain filling rate of low density was higher than medium density and high density.After reaching the maximum grain filling rate,the descent speed of grain filling rate of Hengyu 1182 was faster than Zhengdan 958 and Xianyu 335.The grain-filling processes of maize hybrids with different treatments were analyzed by Logistic model,and the total filling period could be divided into early stage,middle stage and late stage. The Logistic model showed that the peak grain filling rate (G_max) and the average grain-filling rate (G_mean) were higher in Hengyu 1182 whose active grain filling stage(D) was shorter than other 2 varieties,the average filling rate of 3 maize varieties in different filling stage showed that Hengyu 1182 > Xianyu 335 > Zhengdan 958. The ear length,ear diameter,grains per row,rows per ear,and 1000-grain weight decreased with the increased of planting density in 3 varieties,but the barren ear tips was just the opposite.The maximum yield of 3 maize varieties was different,Hengyu 1182 was in the 82 500 plant/ha to achieve the maximum yield,Zhengdan 958 and Xianyu 335 was 75 000 plant/ha,the maximum yield of 3 maize varieties showed that Hengyu 1182 > Xianyu 335 > Zhengdan 958.

Key words: Density, Maize, Leaf area index, Grain filling characteristic

CLC Number: 

• S513.01