Abstract:
Investsgatiosis were carried out to study the effects of varying nitrogen (N) levels on certain physiological
c parameters and yield characteristics of rice with special emphasis on grain grade index. Three short
duration rice varieties viz., ADT 36, DR. 50 and Co 37 were selected and N was applied at five levels viz., 0,50,
100,150 and 200 kg ha'1 along with 50 kg P and 50 kg K ha'1. Experimental results revealed that higher dose
of N increased the total chlorophyll content, soluble protein and nitrate reductase activity in all the three
varieties in vegetative, flowering and harvest stages. Although increased N application had significant
effect on grain yield, there was a negative relationship between grain grade index and N. The comparison of
varieties exhibited the superiority Co.37 in all the physiological and biochemical parameters studied, and in
the grain yield.
