OPTIMIZING RATE OF NITROGEN APPLICATION FOR HIGHER GROWTH AND YIELD OF WHEAT (Triticum aestivum L.) CULTIVARS

In order to optimize the nitrogen rates in three wheat (triticum aestivum l.) cultivars for obtaining higher grain yield, a split plot experiment based on randomized complete block design with three replicates was conducted in the research field of university of agriculture, faisalabad during rabi season 2006-07. among treatments nitrogen levels (n0= 0, n1= 50, n2= 100, n3= 150 kg ha^-1) in main while wheat cultivars (v1= punjnad-i, v2= fareed-2006, v3=uqab-2000) were allocated in sub plots during the course of growing season. traits as plant height, fertile tillers, spike length, spikelets spike^-1, grains spike^-1, 1000-grain weight, straw yield, grain yield and harvest index (hi) were significantly (p=0.05) affected by treatment combinations. maximum grain yield was obtained by v3 (uqab-2000) cultivar when treated with n3 (150 kg ha^-1) fertilizer level. also, results showed that with increasing nitrogen rates, wheat yield increases significantly up to a level of significance (p=0.05). increasing nitrogen levels led to significantly increase in plant height (101.81cm), spike bearing tillers (495.77), grains spike-1 (61.45), straw yield (8.60 t ha^-1) and harvest index (36.17%) of v3 (uqab-2000). in all traits except germination count, v3 (uqab-2000) was found to be superior.