Chemical control of tree vigour and the promotion of flowering and fruiting in mango (<i>Mangifera indica</i>L.) using paclobutrazol

Abstract

SummarySoil application of paclobutrazol reduced internodal length, shoot length and height increments of one to eight year old veneer grafts of three mango cultivars on seedling rootstocks. Soil applications of growth retardant caused precocious flowering in young grafts and promoted flowering in bearing trees. Axillary flowering and cauliflory were observed in treated trees and flowering was advanced. Soil-treated trees given 10 g a.i. per tree flowered six to eight weeks earlier than control trees. In cv. Banganapalli, early-flowered shoots which had failed to set fruits, flowered again at the same time as control trees. Post-harvest applications may be more advantageous than a pre-bloom application, with a longer lag time. There was a significant increase in yield per tree which was even more significant when tree vigour was allowed for. Fruit size and quality were not affected by the treatment. An application rate of 10 g a.i. per tree gave the desired effects for at least two years in five year old bearing trees whereas for one and two year old grafts, 1.25 and 2.5 g per graft respectively were safe and effective. Applications of the growth retardant by foliar spray, on the other hand, had no effect on shoot growth or flowering in any of the experiments.