The experiment was conducted in ban maran village - south east Erbil- at winter season of 2008 for studying split application of nitrogen fertilizer in growth and yield of five wheat varieties. Results was analyzed by using factorial experiment with split plot design.
The studied factors include different methods application of nitrogen fertilizer and wheat varieties, the first method was the application of half quantity after germination stage and other half at the beginning of branching stage, the second method was the application of half quantity after germination stage and other half at the spikes appearance, the third method was the application of one third quantity after germination stage and the second one third at the beginning branching stage and the last one third at spikes appearance.
The five wheat varieties which are studied were Aybaa 99, Sardar, Aksad, Sham 95, Resgari.
Results indicate that the third method gives the highest value of spikes numbers/plant, spike length, and biological yield. In regarding to varieties effects, the Sardar variety gives the highest branching number/plant, leaves number/plant, spike length and grain yield, but the Aybaa 99 variety exceed in the following characters spike number/plant, spike length, weight of 1000 grain, in addition to highest biological yield. There is significant interaction between different methods of nitrogen fertilizer applications and wheat varieties where as the third method for Aybaa 99 gives the highest leaves number/plant, spike number/plant, spike length, and biological yield. But the highest grain yield was achieved by the second method for Sardar variety. For that reason our recommendation is the planting of Sardar and Sham 95 varieties with split application of nitrogen fertilizer during different plant´s growth stages.