YIELD AND YIELD ATTRIBUTES OF WHEAT (Triticum aestivum L.) AS INFLUENCED BY EXOGENOUS APPLICATION DOSE AND TIME OF NAPHTHALENE ACETIC ACID (NAA)

Abstract

An experiment was carried out at Agronomy research field, Department of Agronomy, Hajee Mohammad Danesh Science and Technology University, Dinajpur during December 2022 to April 2023 to evaluate the effect of dose and time of naphthalene acetic acid on growth and yield of wheat (BARI Gom-32). The experiment was comprised with two factors namely, Factor A: Doses of naphthalene acetic acid viz. D1 = 0 ppm of NAA (control), D2 = 10 ppm of NAA, D3 = 20 ppm of NAA and D4 = 30 ppm of NAA and Factor B: Application time of naphthalene acetic acid viz. T1 = 25 days after sowing (DAS), T2 = 50 days after sowing (DAS) and T3 = 75 days after sowing (DAS). The experiment was laid out following Randomized Complete Block Design (RCBD) with three replications. The total plot number was 36 in the experiment. The area of the unit plot was 2.5 m × 2 m. The results revealed that significant variations existed between the varieties in respect of morphological characteristics and yield contributing characters like plant height, length of spike (cm), number of spikelets spike-1, grains spikelet-1, grains spike-1, 1000-grain weight, grain yield (t ha-1), straw yield (t ha-1), biological yield (t ha-1) and harvest index (%). The highest result for plant height at different days interval at 20 DAS plant height was non-significant, 60 DAS plant height was highest at D2 (73.98 cm) and at 40, 80 DAS and at harvest (37.61cm, 98.50 cm, 104.36 cm), length of spike (16.54 cm), number of spikelets spike-1 (16.78), grains spikelet-1 (3.22), grains spike-1 (54.13), 1000-grain weight (52.95 g ), grain yield (4.46 t ha-1), straw yield (5.15 t ha-1), biological yield (9.61 t ha-1), harvest index (46.14 %) were recorded at D4 (NAA concentration). On the other hand, lowest results were recorded from control treatments. The plant height was non-significant at 20 DAS, at 40 DAS plant height was highest at T3 (35.66 cm) and at 60, 80 DAS and at harvest (73.30 cm, 95.11 cm, 102.68 cm), length of spike (15.68 cm), number of spikelets spike-1 (16.03), grains spikelet-1 (2.61), grains spike-1 (42.01), 1000-grain weight (50.52 g ), grain yield (4.07 t ha-1), straw yield (4.88 t ha-1), biological yield (8.93 t ha-1), harvest index (45.11 %) were recorded T2 at 50 DAS. Control treatment (0 ppm of naphthalene acetic acid) at 25 DAS gave lowest result for all parameters. Maximum yield was recorded from combined effect (D4T2) of 30 ppm naphthalene acetic acid at 50 DAS. For the better growth and yield exogenous application of naphthalene acetic acid 30 ppm at 50 DAS (D4T2) can be used as combined treatment. Thus, NAA (30 ppm) would be successfully used for commercial wheat production.