Growth Restoration Studies in Frost-Affected Mango ( Mangifera indica L.) Orchards in Sub-Himalayan Region

Frost is a major constraint in mango production in the sub- Himalayan region. To restore growth and productivity in frost-affected Dashehari mango orchards, effect of different growth-restoring treatments was studied at highly frost-sensitive, medium frost-sensitive, low frost-sensitive and frost-free locations. Foliar application of urea, benzyladenine, gibberellic acid (individually or in combination) was made during the post-spring season. As the cut ends of branches or damaged open area serve as entry points for the propagation of ice crystals through the vascular system in plants, the experiments were also carried out with and without prior winter covering of cut ends of branches with wax or polythene cover. At low and high frost-sensitive locations, 7 and 5.5 number of news shoots emerged, on average, per scaffold when frost-affected trees were sprayed with benzyladenine (BA 20ppm), followed by 2% urea spray after fifteen days. Better restoration of reproductive growth was observed with this treatment. Pre-winter waxing or polythene covering of the cut ends of branches was very effective in preventing lethal frost-damage (stem injury below 20cm) to the trees. Effect of benzyladenine and urea treatments was found to be additive in trees whose cut surfaces were waxed or covered with polythene sheets.