Effect of Phosphorus and Gibberellic Acid on Growth and Yield of Tuberose (Polianthes tuberosa)

The present study was carried out in the Horticulture farm of Sher-e-Bangla Agricultural University, Dhaka, Bangladesh during October 2017 to March 2018 to study the Effect of phosphorus (P) and gibberellic acid (GA3) on growth and yield of tuberose (Polianthes tuberosa). Four phosphorus levels viz P0 = 0 kg P2O5 ha-1, P1 = 65 kg P2O5 ha-1, P2 = 85 kg P2O5 ha-1 and P3 = 110 kg P2O5 ha-1 and three GA3 levels viz. G0 = 0 ppm GA3, G1 = 115 ppm GA3 and G2 =145 ppm GA3. The experiment was laid out in the two factors Randomized Complete Block Design (RCBD) with three replications. Regarding P application, P3 gave the highest plant height (61.02 cm) and number of leaves plant-1 (7. 29.35) compared to control treatment but the highest yield parameters no. of spike ha-1 (368.60 thousand), bulb yield (25.88 t ha-1) and bulblet yield (14.21 t ha-1) were found from the treatment P2 whereas control treatment P0 showed lowest results. In case of GA3 application, G2 showed highest growth and yield parameter and the highest no. of spike ha-1 (362.30 thousand), bulb yield (25.38 t ha-1) and bulblet yield (14.00 t ha-1) were obtained from G2 whereas the lowest results were found from the control treatment G0. Treatment combine of P and GA3, the highest no. of spike ha-1 (405.60 thousand), bulb yield (31.45 t ha-1), and bulblet yield (16.01 t ha-1) were found from P2G2 combination whereas the lowest no. of spike ha-1 (189.60 thousand), bulb yield (14.57 t ha-1) and bulblet yield (9.05 t ha-1) was found from the control treatment combination of P0G0. In terms of economic analysis, the highest gross return (Tk. 471550), net return (Tk. 289337) and BCR (2.59) were also obtained from P2G2 whereas the lowest gross return (Tk. 227470), net return (Tk. 57703) and BCR (1.34) was obtained from P0G0. From the above results, it can be stated that that the P application @ 85 kg P2O5 ha-1 and GA3 application @ 145 ppm can be considered for higher yield and economic return in commercial cultivation of tuberose.