Study on Growth of Super-high-yield Summer Maize in the Ecological Area of the Yellow River,Huai and Hai Rivers

Field experiments were conducted to study the yield components,leaf area index (LAI),SPAD,dry matter accumulation and grain-filling rate of summer maize between super-high-yield field (15 000 kg/ha) and high-yield field.The results showed that summer maize yield in the super-high-yield field increased by 15.6% than high-yield field,grains per ear was 3.7% and 100-seed weight was 8.9%,super-high-yield hung on the skirts of seed weight.After silking stage,the LAI,SPAD and dry matter of super-high-yield summer maize were higher than high-yield.Grain-filling rate was higher than high-yield in 10-40 d after silking,and remained certain level after silking 50d.However,maize plants in high-yield were senescence.Summer maize had the larger LAI,more dry matter accumulation,higher chlorophyll content and longer grain filling periods in the super-high-yield field,and achieved super-high-yield by increasing effectively the grain number and grain weight.