Vol. 4, Issue 2, Part E (2022)

The present study was conducted during the year 2019 - 2020 with objectives to study the effects of nitrogen application in yield and yield attributes of mutant and parent rice varieties and to estimate the nitrogen uptake and use efficiency of mutant and parent rice varieties. The soil of the experimental field exhibited neutral soil pH i.e. 7.29, Electrical conductivity 0.16 dS/m, low organic carbon content (0.35), low soil available nitrogen (210.62 kg/ha), high soil available phosphorus (31.53 kg/ha) and high soil available potassium (437.68 kg/ha). The experiment was conducted in split-plot design and replicated thrice, consisting four nitrogen levels (0, 60, 80 and 100 kg N / ha) as main factor and four varieties as sub factor. There were total 16 treatment combinations. Two new high-yielding mutant varieties of paddy i.e. C.G. Javaphool Trombay and Sonagathi Mutant-1 were developed from two traditional varieties of paddy Javaphool and Sonagathi by gamma irradiation method of inducing mutation. Morpho-physiological parameters and nutrient content were analyzed plot wise and calculated to hectare basis. Likewise, soil samples were collected, processed and utilized for determining physico-chemical properties of soil. Among all varieties, Sonagathi mutant-1 (30.12%) and C.G. Javaphool Trombay (27.04%) were more efficient in utilizing nitrogen than Sonagathi parent (26.93%) and Javaphool parent (23.28%). Nitrogen use efficiency increased up to 80 kg N / ha then it further decreased at 100 kg N / ha. The treatment combination N₈₀V₃ viz., Sonagathi Mutant-1 with 80 kg N/ha application was found to be superior among all combinations in terms of nitrogen use efficiency.