**1. Introduction**

One of the most important elements in fruit orchard management is growth control. Excessive vigour reduces light penetration, yield, fruit quality and an increase in cost of pruning and pest control [1]. On the other hand, many cultivars may set very large number of fruits with unacceptably smaller size and often serious reduction in return bloom and fruit set may occur in the following year leading to biennial bearing. About 20–80% of the fruit which initially sets drop-off from the tree during various stages of development. Thus, various plant growth regulators are used for the control of vegetative growth, flowering of young trees, thinning of flowers and fruits, delaying fruit abscission, regulation of fruit ripening and improvement of fruit production and quality in bearing trees [2]. Various chemicals are used in horticulturally advanced countries to reduce the amount of pruning. Among the various growth control chemicals tested, paclobutrazol (PB) is one of the most successful and widely used in fruit trees that can retard tree

growth. Besides this, it also increases fruit set the years following application as a carryover effect. Paclobutrazol treatments have also shown to increase Delicious fruit firmness at harvest, [3]. Paclobutrazol, a gibberellins inhibitor, has been effectively used in reducing canopy volume and increasing flower intensity in peach [4], plum [5], almond [6], grapes [7] and mango [8]. Paclobutrazol is effective not only in flower induction but also in early and off season flower induction in mango [9, 10]. Paclobutrazol application in McIntosh apple trees shortly after full bloom affected fruit quality characteristics with respect to accelerated colour development, delayed and synchronised fruit maturation, control of preharvest fruit drop and maintenance of better fruit quality during storage [11]. Sebastian et al. [12] also reported that the foliar application of plant growth regulators improves the yield and quality of fruit crops. However, the action of plant growth regulators (PGRs) is highly specific to plant species, cultivar and stage of development, and strongly dependent on its rate of application and environmental conditions [13].
