An experiment was conducted at the Agronomy Field Laboratory of Bangladesh Agricultural University, Mymensingh during the period from July to December 2018 to evaluate the effect of different levels of nitrogen on growth and yield of drought tolerant transplant aman rice cultivars. The ex- periment was consisted of one check variety BRRI dhan49 and three drought tolerant rice varieties BRRI dhan56, BRRI dhan66 and BRRI dhan71 along with five nitrogen levels such as no nitrogen (control treatment), 50%, 100%, 125% and 150% of recommended dose (RD) where the recommended dose was 150 kg N ha−1. Nitrogen was applied in the form of urea (46.66% N) as top dressing in three equal splits at 15 days after transplanting, 30 DAT and 45 DAT. The experiment was laid out in a randomized complete block design with three replications. The result of the study reveals that BRRI dhan66 produced the highest number of total tillers hill−1, effective tillers hill−1 and grains panicle−1. The highest 1000-grain weight and grain yield was recorded in BRRI dhan71 which was statistically identical to BRRI dhan66. In case of level of nitrogen, the highest number of total tillers hill−1 was observed in 125% RD of N. The highest number of effective tillers hill−1 was found in 100% of RD of N and the maximum number of grains panicle−1 was observed in 150% of RD of N. The highest grain yield was obtained from 125% RD of N which was statistically identical to 100% and 150% of RD of N. In case of interaction the highest number of total tillers hill−1 was recorded in BRRI dhan56 with 125% RD of N which was statistically identical to BRRI dhan66 with 100% RD of N. The highest number of grains panicle−1 was observed in BRRI dhan66 with 150% of RD of N. BRRI dhan56 with 150% RD of N produced the highest 1000-grain weight. The highest number of effective tillers hill−1, grain yield and straw yield were recorded in BRRI dhan66 with 100% RD of N. In conclusion, the result of the study revealed that application of 100% recommended dose of N (150 kg ha−1) is suggested as the best nitrogen management approach for the drought tolerant rice cultivar BRRI dhan66 for its better performance.
Key words: Drought tolerance, Modern Aman rice cultivars, Nitrogen fertilization, crop productivity
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