Effect of N Rates,Densities on Yield of Certain Egyptian Maize Hybrids

Many factors affect maize grain yield such as varieties, fertility and plant population density. Results indicated that increasing N rates increased leaf area plant-1, LAI, dry matter contents in different plant organs at 60 and 90 days from planting as well as crop growth rate (CGR) and net assimilation rate (NAR). Increasing N rates increased grain yield from 90 to 120 and 150 KgN/fad by 2.3, 1.5 ard fad-1, respectively. Increasing plant population densities from 24000 to 30000 plants fad-1 significantly decreased leaf area, LAI, dry matter contents in different plant organs and whole plant, (CGR) and (NAR) after 60 and 90 days from planting. The studied maize hybrids differed significantly by nitrogen fertilization and plant population densities. SC10 and TWC310 exhibited better growth characteristics and high grain yield than the other two studied hybrids (SC122 and TWC352).