EFFECT OF BULB SIZE AND GA3 ON GROWTH, FLOWERING AND YIELD OF TUBEROSE

Abstract

The experiment was conducted in the Horticulture Farm of Sher-e-Bangla Agricultural University, Dhaka, Bangladesh during the period from April 2006 to January 2007. The experiment comprised two factors, such as Factor A: Bulb size (3 sizes of bulb) i.e. small (1-1.5 cm), medium (> 1.5-2.0 cm) and large (>2.0-2.5 cm); Factor B: GA3 (6 levels of GA3) i.e. 0 ppm, 100 ppm, 150ppm, 200 ppm, 250 ppm and 300 ppm.The experiment was laid out in Randomized Complete Block Design with three replications. Data were collected in respect of growth characters and yield of bulb, bulblet and spike of tuberose. The minimum days (76.59) required for emergence of spike was recorded from large size bulb and maximum days (81.63) required for emergence of spike incase of small size bulb. The tallest tuberose plant (66.76) was recorded from large size bulb. The maximum weight of single bulb (45.48g) was found from large size bulb. The highest number of bulblet /plant (14.57) was obtained in large size bulb and the lowest number of bulblet /plant (13.16) was recorded in small size bulb. The maximum yield of bulb (9 .10 t/ha) and bulblet (11.44 t/ha) was found in large size bulb and the lowest yield of bulb (7.50 t/ha) and bulblet (9.13 t/ha) was obtained from small size bulb. In gibberellic acid (GA3) the minimum (75.98) days required for emergence of spike was recorded from 300ppm. The maximum number of side shoot of tuberose plant (21.18) was obtained from 300ppm. The maximum yield of bulb (8.76 t/ha) and bulblet (12.14 t/ha) was found in 300 ppm GA3 and the lowest for control. There were no interaction effects between bulb size and different concentrations of GA3 in terms of all the recorded character under the present investigation. The highest gross return (TK.896665) was obtained from the treatment combination of large size bulb and GA3 at 300 ppm. The maximum (3.29) benefit cost ratio was attained from the treatment combination of large size bulb and GA3 at 250 and 300 ppm.