EFFECT OF SPLIT NITROGEN APPLICATION ON GROWTH AND YIELD OF WHEAT (TRITICUM-AESTIVUM L) GENOTYPES WITH DIFFERENT N-ASSIMILATION POTENTIAL

A field experiment was conducted with different nitrogen regimes to as sess the growth and yield performance of wheat genotypes which differ in nitrate assimilation potential. Genotypic differences in biomass ac cumulation were observed at different growth stages. The nitrogen trea tment had little effect on biomass accumulation at early stages of gro wth, while at later stages of growth there was enhanced biomass accumu lation when N was applied in more than two splits. On an average, geno types with high nitrate reductase activity (the 'HNR' genotypes) accum ulated 14.2 % more biomass than the genotypes with low nitrate reducta se activity ('LNR' genotypes) when an extra dose (40 kg N ha(-1)) of n itrogen was given at the time of anthesis. The application of nitrogen in more than two splits increased grain yield of both 'HNR' and 'LNR' genotypes mainly by increasing grain weight per ear. The application of an extra dose of nitrogen (40 kg N ha(-1)) at the time of anthesis increased grain yield of 'HNR' genotypes by 38.5 % as compared to 'LNR ' genotypes.