Effect of foliar application of growth regulators on flowering of tuberose (Polianthes tuberosa L.)

Field experiment was conducted during 2008–09 and 2009–10 to find out the effect of foliar spray of growth regulators in three doses each in GA₃ (50, 100 and 150 ppm), Kinetin (50, 100 and 150 ppm), NAA (50, 100 and 150 ppm), Ethrel (100, 200 ad 300 ppm) and SADH (100, 200 and 300 ppm) on the flowering of two cultivars of tuberose viz., Shringar and Kalyani Double. Cultivar Shringar was superior in inducing early spike emergence, first floret opening and also produced maximum number of spikes/m². However, cv. Kalyani Double showed maximum number of florets and spike length and flowering duration. Among various treatments, GA₃ (150 ppm) was observed best in inducing early spike emergence, opening of first floret, 50 per cent floret opening and maximum spike yield per sq. meter. The spikes characters, such as length of rachis and spike, number of florets per spike, increased significantly with the application of GA₃ (100 ppm). Maximum days to withering of first opened floret and flowering duration were observed with Kinetin (150 ppm). However, Ethrel (300 ppm) exhibited delayed flowering, minimum flowering duration and reduced length of spike characters.