Periodic nitrate reductase activity, nitrogen assimilation and its relationship to grain protein in field grown wheat

Investigations were carried out during rabi 1999–2000 to find out effect of isoproturon treatments on nitrate reductase activity, nitrogen content and grain protein of wheat variety HPW-89. Among all the treatments, application of isoproturon 1.5 kgha⁻¹ (35 DAS) recorded maximum increase in nitrate reductase activity, nitrogen content and protein content at all the stages of development. Irrespective of treatments nitrate reductase activity, nitrogen content and protein content in leaves increased upto 30 days after herbicide application and thereafter declined upto 120 days after herbicide application. A positive Significant correlation was obtained between nitrate reductase activity and grain protein and between leaf protein and grain protein.