effect of different amounts of foliar- and soil- applied n on yield and yield components of promising bread wheat (triticum aestivum) lines in gorgan

effect of different amounts of foliar- and soil- applied n were evaluated in a factorial arrangement of rcbd with three replications at the agricultural research station of gorgan in 2004-2005 growing season. two promising lines of bread wheat, two levels of foliar application of nitrogen (0 and 5%) at tillering and booting stage, with five rates of 0, 45, 90, 135 and 180kg n/ha as urea were used. anova results showed that grain and biological yield increased from 4130 and 9529 kg/ha to 5399 and 13400 kg/ha at 0 and 180kg n/ha, respectively. foliar application of nitrogen did not affect grain yield of studied lines. grain yield was not significantly affected by n foliar application, while it increased yield about 120 kg.ha-1. with increasing of n rate, spike length increased significantly. increasing of grain yield due to soil-applied n might be attributed to increase in number of seeds per spikes.