RESPONSE OF RICE (ORYZA-SATIVA) VARIETIES OF DIFFERENT DURATIONS TO LEVEL OF NITROGEN IN COASTAL ALLUVIAL SOILS OF ORISSA IN WET SEASON

A field experiment was conducted during the wet season of 1991-93 in c oastal alluvial soils of Cuttack (high-rainfall region), to identify s uitable varieties of rice (Oryza sativa L.) of different maturity dura tions and their response to nitrogen application. The promising variet ies with higher yield potential identified were 'Gayatri', 'Pankaj' an d 'IET 8002' in the long-duration group (150-165 days): 'IR 36', 'IET 9979' and 'IET 8585' in the medium-duration group (125-135 days); and 'IET 8887' and 'IET 8944' in the short-duration group (95-105 days). T he mean optimum and yield-maximizing N doses were respectively 84.7 an d 89.5 kg/ha for long-duration group. 75.6 and 83.4 kg/ha for medium g roup and 38.1 and 42.1 kg/ha for early group. Long-duration photo-sens itive varieties of 150-165 days were the highest yielders (mean yield 4.2 tonnes/ha in 2 years), responding better to N application than oth er groups of varieties.