Effect of growth regulators on growth and flowering in tuberose under north India conditions

The present investigation was carried out with three different growth regulators, namely GA₃, IAA and NAA applied as dip treatments in two tuberose cultivars, viz. Calcutta Single and Calcutta Double. The vegetative characters like days required for sprouting could be manipulated with the application of 150 ppm A as dip treatment in both the cultivars (9.28 and 9.06 days, respectively). Besides, the important flower traits like vase-life of spike could be enhanced with the application of 100 ppm IAA in both the cultivars (13.0 and 11.57days respectively in Calcutta Double and Calcutta Single) compared to the control (9.0 and 11.0 days respectively). Even application of 100 ppm IAA increased the spike length (63.82 and 98.73 cm in Calcutta Double and Calcutta Single) compared to the respective control (57.27 cm and 84.29 cm). Application of 250 ppm GA₃ as dip could enhanced the number of bulbs and bulblets per plant in both of the cultivars (25.50 and 18.46 respectively in Calcutta Double and Calcutta Single) compared to the respective control (18.6 and 12.0), thereby enhancing the propagation coefficient (825.11 and 456.78 respectively in Calcutta Double and Calcutta Single) than the respective control (729.09 and 409.09). It can be concluded that growth regulators as dip treatment directly influenced the vegetative, some of the floral and most of the bulbous characteristics.