Journal of Applied Horticulture. 1999: 1(2): 84-88

Hormonal physiology of flowering in 'Dashehari' mango

Sant Ram

G.B. Pant University of Agriculture and Technology, Pantnagar-263 145, U.P., India.

Studies were conducted on alternate bearer mango cv. Dashehari. Dashehari produced a major vegetative flush in March-April followed by 2 minor flushes in June-July and September-October. The major vegetative flush fruited, whereas the other 2 minor flushes did not. Shoots which fruited rarely produced a new vegetative flush soon after crop harvest and also did not flower and fruit in the following season. To promote vigour and productivity, such shoots were forced to produce vegetative growth soon after crop harvest by pruning and application of 1-2% urea. Such treatments failed to induce flowering and fruiting. The concentrations of endogenous growth regulators were determined in shoots. Shoot-tips contained 3 auxins, 8 gibberellins, 11 cytokinins, 11 steroids and an ABA-like inhibitor. High concentrations of auxins, inhibitors, cytokinins and steroids were observed in shoot-tips just prior to or during the period of flower bud differentiation, whereas low concentrations of gibberellins were observed. Gibberellins were identified as inhibitors of flowering in Dashehar. The application of paclobutrazol to soil antagonised gibberellin production in new shoots and induced flowering and fruiting.