ABSTRACT
A field experiment was carried out in the fields of the college of agricultural engineering sciences, university of Baghdad during the fall season of 2021, in order to find out which of the cultivated genotypes of maize are efficient under nitrogen fertilization. The experiment was applied according to a RCBD (split plot design with three replications). The genotypes of experiment (Baghdad, 5018 and Sarah) and supplying three levels of nitrogen fertilizer, which are N1 (100 kg/ha), N2 (200 kg/ha) and N3 (300 kg/ha), the results of the statistical analysis are showed the superiority of the cultivar Sarah in the trait of number of days until 50% silking, chlorophyll index, number of pods per plant, number of grains per row and number of seeds per row, where their averages were 61 d, 590.27 mg/m2, 2.0 ear-1, 48.78 grains/row and 818.07 ear-1 respectively, there were no significant differences between the genotypes in the traits of number of rows per ear, weight of 100 grains and total grain yield. The increase in nitrogen fertilizer caused an increasing of traits, especially at the highest level N3, where it gave the highest average of the number days 50% tasseling, the number of silking 50%, the number of ears per plant, the number of rows per ear, the number of grains per row, the number of grains per ear, and weight 100 grains, and caused of increasing of characteristic of the total grain yield, and the averages were 59 d, 63.11 d, 2.2 earbuds-1, 18.622 ear-1, 48.78 grains/row, 993.0 grains/ear, 31.78 g, and 14. 88 tons/ha respectively.
