Kotoky, U.Bakhtari, Wahedullah2022-07-182022-07-182020-07https://krishikosh.egranth.ac.in/handle/1/5810185522An experiment was conducted on Assam Lemon (Citrus limon L.) at the Experimental Farm, Department of Horticulture, Assam Agricultural University, Jorhat during 2018-2019 to study the “Effect of growth regulators on Assam Lemon (Citrus limon L)”. Six treatments with four replications were laid out in a Randomized Block Design. The treatments comprised of GA3 (60, 80 and 100ppm) and NAA (30, 40 and 50ppm). The growth regulators were applied as foliar spray at three growth stages: (1) at pre flowering stage in the month of November, 2018, (2) at flowering stage and (3) one month after fruit set. The plant growth regulators showed significant response on flowering. The minimum number of days (52.67days) was recorded in T2 (GA3 80ppm) from the date of plant growth regulators application and the highest number of days were required in case of T6 treatment (NAA 50ppm). The highest number of flowers per plant (476.74), highest fruit set (81.32%) and the lowest fruit drop (18.50%) was recorded from T2 (GA3 80ppm) during the experiment. Number of fruits per plant was recorded highest in GA2 80ppm (371.33) and the lowest in T6 (NAA 50ppm). The highest fruit weight (136.53g), fruit length (10.00cm), fruit girth (15.93 cm), fruit volume (162.89cc) and yield (52.72 t/ha) were recorded in T2 (GA3 80ppm) while the lowest values were recorded in T6 (NAA 50ppm). The results revealed that, pulp weight and pulp-peel ratio were significantly influenced by growth regulator applications. The highest pulp weight (108.32g) and the highest pulp-peel ratio (4.83) were recorded in T2 (GA3 80ppm). Peel thickness was lowest (0.48cm) in T2 (GA3 80ppm) and the highest of 0.73cm was recorded in T6 (NAA 50ppm).The results revealed that, T2 (GA3 80ppm) took the lowest number of days required for flowering to harvesting (102.47 days) and the highest (133.77 days) in T6 (NAA 50ppm). Regarding the total leaf chlorophyll content, the highest was recorded (1.29mg/g of fresh weight) in T2 (GA3 80ppm). However, there were no significant differences in leaf nitrogen and leaf phosphorous among the treatments. Highest leaf potassium (1.69%) was recorded in T1 (GA3 60ppm). The highest juice content (37.29cc) was recorded in T2 (GA3 80ppm). The highest TSS (5.18°Brix), titrable acidity (3.50%) and TSS-Acidity ratio (1.48) was recorded in T1 (GA3 60ppm), whereas, the lowest values were recorded in T6 (NAA 50ppm). From the results of the ascorbic acid content (32.15mg/100ml) the highest was recorded in T2 (GA3 80ppm). Regarding evaluation of the economics of cultivation, it can be concluded that, the highest benefit-cost ratio of 3.52 was obtained from T2 (GA3 80ppm) followed by 3.44 from T1 (GA3 60ppm). The lowest B:C ratio (2.41) was recorded in T6 (NAA 50ppm). Thus, it can be suggested that, GA3 at 80ppm is the most economical plant growth regulator to improve flowering, yield and quality of Assam Lemon.EnglishThesis