LEAF NRA AND ITS RELATIONSHIP WITH GRAIN AND PROTEIN YIELD OF TRITICALE AS AFFECTED BY PROGRESSIVE APPLICATION OF NITROGEN AND PHOSPHORUS-FERTILIZER LEVELS

Four cultivars of triticale along with one check cultivar each of brea d wheat and rye were field grown at Aligarh, India, to determine the e ffect of progressive application of combined nitrogen + phosphorus (NP) fertilizer levels on nitrate reductase activity (NRA) in flag and p enultimate leaf at three stages of crop development. Leaf NRA increase d with increasing combined N+P levels up to 240 kg N+P/ha. Later, ther e was a general decrease in the activity of the enzyme despite increas ing N and/or P in the fertilizer combinations. Leaf NRA was declined w ith the successive growth stages (tillering > heading > milky grain) a s well as with the leaf age (unexpanded flag leaf > expanded flag leaf >penultimate leaf) at the corresponding stages. Moreover, the cultiva rs catagorically exhibited positive correlations between NRA levels an d grain and protein yield at different growth stages, indicating towar ds the possibility of utilizing leaf NRA as a physiological parameter during the screening of improved cultivars of triticale.