Evaluation of Yield and Yield Attributes in Various Rice Genotypes under Different Nitrogen Levels

The experiment was conducted during 2017, Pishanam season at Rice Research Station, Ambasamudram with the objective to screen the efficient and responsive rice genotypes based on nitrogen use efficiency and yield and yield attributes of different genotypes by N levels with 32 rice genotypes as main plot treatments and four nitrogen levels N0 (control), N1 (50% recommended dose of N ha-1), N2 (100% recommended dose of N ha-1) and N3 (150% recommended dose of N ha-1) as subplot treatments. The experimental results showed that, the highest grain and straw yields were recorded at N3 (180 kg ha-1) by the most of the rice genotypes, except the AS 12051, ACK 14004, CB08702, CB 13539 and PM 12009 which were not responded genotypes for higher dose of (180 kg ha-1) nitrogen. In the genotypes ASD 16, ADT 43, ADT 45, CO 51, MDU 5, CB 14508, CB 14533, TR 0927, TR 13069 and TM 12061 the AE was increasing with increasing level of nitrogen, other genotypes showed decreasing trend with increasing level of nitrogen levels. The genotypes viz., ASD16, ADT39, ADT45, TPS 5, AD09206, CB06803, ACK14001, TM10085, TM12007, PM12009 and EC725224 are under Efficient and responsive (ER) category which gives average yield at low level and high N use efficiency. The plant height, productive tillers, total grains, harvest index, panicle length and 1000 grain weights given verified results among the genotypes due to genetic characters. Among the N levels the plant height, panicle length, productive tillers per hill and total grains showed highest in 180 kg N ha-1. 1000 grain weight increased at low level of 50% of RDN (21.0) and decreased to 20.8 in N2 and N3 treatments which indicated higher doses of N. N harvest index were decreased with increasing level of N application from 0.70 (N0), 0.65(N1), 0.64 (N2) and 0.63 (N3).