Promotion of flower bud differentiation and improvement of bisexual flower formation in 'Irwin' mango.
Yamashita K., Ogawa S.
Author Affiliation: Faculty of Agriculture, Miyazaki University, Gakuen Kibanadai-nishi 1-1, Miyazaki-shi, 889-2192 Japan.
Japanese Journal of Tropical Agriculture 42 : 153-158
Abstract : The effects of cytokinin application and night temperature on flower bud differentiation and bisexual flower formation were investigated in Irwin mangoes. Benzyladenine at 50 ppm or paclobutrazol at 50 ppm was applied as a soil drench to young potted trees at the end of September. These trees were transferred to a greenhouse at the end of November and grown with a night temperature from the end of December. Benzyladenine promoted flower bud differentiation while paclobutrazol did not. In a second experiment, young potted trees grown outdoors were transferred into a greenhouse at the end of December and kept at a night temperature of 30° or 20°C until flowering. The effects of applying a soil drench of 50 ppm benzyladenine were examined at a night temperature of 20°. The percentage of bisexual flowers increased in response to a night temperature of 30° (particularly in the basal part of panicles) or to a night temperature of 20° combined with benzyladenine treatment (particularly in the apical section of panicles). In a third experiment on trees at the balloon stage in a plastic house, panicles 3 or 8 cm long were sprayed with 500 ppm benzyladenine or 500 ppm kinetin. Both these cytokinins increased the percentage of bisexual flowers in panicles 8 cm long but not in those only 3 cm long.