Response of different rice (Oryza sativa) hybrids and varieties to graded levels of nitrogen during wet and dry seasons in coastal Orissa

Abstract

A field experiment was conducted to find out response of different rice (Oryza sativa L.) hybrids and conventional varieties to nitrogen during wet and dry seasons of 1997 to 1999 to Cuttack (coastal Orissa region-alluvial soils). During wet season, the conventional variety 'CR 749-20-2' gave the highest grain yield (3 943 kg/ha) and was superior to all the other test varieties as well as hybrids. Among hybrids, only 'Pro Agro 6201' was at par with 'CR 749-20-2' in terms of yield performance during 1998 wet season, while during the other 2 years it was only next best. However during dry seson the hybrid'Pro Agro 6201' was superior in terms of yield potential to all the other hyubrids and varieties including 'CR 749-20-2'. The other hybrids 'DRRH 1' and PAC 831' were comparable to 'Pro Agro 6201' in different years. In general, all the hybrids except 'PAC 861' and 'VRH 704' performed better during dry season and were superior to the conventional varieties in terms of yield. The hybrids and varieties responded significanlty up to 100 kg N/ha during wet seasin and 120 kg N/ha during dry season. Nitrogen-use efficiency (kg grain/kg N applied) was also higher in dry season (10.85-43.5) than wet season (0.33-18.4). The N response was quadratic. The optimum N levels were worked out to be 70.1 to 131.0 kg/ha during wet season and 128.1 to 203.8 kg/ha during dry seson. The results indicated that rice hybrids perform better in dry season than wet season under coastal Orissa condition.