Effects of bulb types and plant growth regulators on the growth and flowering of tuberose (Polianthes tuberosa L.)

Plant growth regulators have significant role in modifying the growth and flowering of plants. An experiment was conducted at the Landscaping Section of the Department of Horticulture, Bangladesh Agricultural University, Mymensingh during the period from March to October, 2018 to investigate the effects of bulb types and plant growth regulators on growth and flowering of tuberose. The two-factor experiment consisted of two bulb types viz., single (S1) and double (S2), and different levels of plant growth regulators viz., = control (T0), GA3 @ 200 ppm (T1), GA3 @ 400 ppm (T2), NAA @ 100 ppm (T3) and NAA @ 300 ppm (T4). The experiment was laid out in Randomized Complete Block Design with three replications. Bulb types and plant growth regulators had significant effects on almost all the parameters under study. The highest flower yield (25.35 t/ha) of tuberose was recorded from the double bulb while the lowest flower yield (22.53 t/ha) of tuberose was obtained from single bulb. The highest flower yield (26.10 t/ha) of tuberose was obtained from GA3 @ 400 ppm, whereas, the lowest flower yield (12.20 t/ha) was recorded from control treatment. Combined treatment of double bulb with GA3 @ 400 ppm gave the highest flower yield (28.91 t/ha) of tuberose while combined treatment of single bulb with control treatment provided the lowest flower yield (14.63 t/ha). Therefore, double bulb along with the application of GA3 @ 400 ppm was found to be better in respect of growth and flowering of tuberose.