RÉSUMÉ
An experiment was conducted at Shradhay Bhagwati Singh Agriculture Research Farm (Hajipur), Chandra Bhanu Gupta Krishi Snatakottar Mahavidyalaya, B.K.T., Lucknow (Uttar Pradesh) during the Kharif season of 2022. The experiment was laid out in split plot design with three replications keeping three ages of seedlings viz., 21 days of the age of old seedlings, 28 days of the age of old seedlings and 35 days of the age of old seedlings in main plots and three plants spacing 20 cm x 10 cm, 25 cm x 10 cm and 15 cm x 15 cm in subplots. Results revealed that there was significant variation among different times of transplanting with respect to growth. Growth parameters were higher in paddy transplanted at 21 days of age of old seedlings as compared to the rest of the age of seedlings. The yield attributes as effective tillers m-2, panicle length (cm.), numbers of grains panicle-1, grains weight panicle-1 (g.), panicle weight (g.) and 1000 grain weight were significantly superior in paddy transplanted in 21 days of age of old seedlings. 21 days of age of old seedlings proved significantly superior in terms of grain, straw, total biological yield and harvest index when compared to the rest of the age of seedlings. The maximum N – content (%) was significantly superior in paddy transplanted in 35 days of the age of seedling in grain and straw. The N – Uptake (kg/ha.) was significantly superior in paddy transplanted in 21 days of age of seedling in grain and straw. The protein content (%) was significantly superior over in paddy transplanted at 35 days of the age of seedlings in grain and straw. The Protein – production (kg/ha.) were significantly superior in paddy transplanted at 21 days of age of seedling in grain and straw. Growth parameters such as plant height (cm.), dry matter accumulation (gm-2) and leaf area index were higher in paddy transplanted with 20 cm x 10 cm but a number of tillers (m-2) higher with 25 cm x 10 cm as compared to rest of the plant spacing. Plant spacing of 25 cm x 10 cm produced significantly more yield attributes and yield of rice. The maximum N – content (%) were significantly superior in paddy transplanted with 15 cm x 15 cm in grain and straw. The maximum N – Uptake (kg/ha.) was significantly superior in paddy transplanted with 25 cm x 10 cm in grain and straw as compared to the rest of the plant spacing. The maximum protein content (%) were significantly superior over in paddy transplanted with 15 cm x 15 cm in grain and straw. The Protein – production (kg/ha.) was significantly superior in paddy transplanted with 25 cm x 10 cm in grain and straw. Transplanting of paddy 28 days of age of old seedlings with 25 cm x 10 cm plant spacing had higher gross return, net return, and B:C ratio of rice crop.