Genotype differences on nitrogen use efficiency among maize hybrids

A field experiment with eight maize hybrids cultivated mainly in Beijing was conducted to investigate the genotypic differences in grain yield, shoot N accumulation and N use efficiency under two N level conditions. The results showed that the variation range of grain yield among maize hybrids were 62% and 57%, total shoot N accumulation were 55% and 48%, respectively. Nongda 108 had the highest grain yield and shoot N accumulation, and Zhongdan 120 and Zhongdan 2 were the lowest ones. With increased N application, N uptake efficiency and N use efficiency decreased significantly, whereas N utilization efficiency almost the same. Genotypic variation in N use efficiency depended mainly on uptake efficiency at both N levels.