Studies on irregular bearing of mango (Mangifera indica L.) IV. Changes in endogenous growth regulating substances in relation to fruit-bud differentiation.
Sanyal D., Mitra S. K., Bose T. K.
Author Affiliation: Department of Horticulture, Bidhan Chandra Krishi Viswavidyalaya, Kalyani 741?235, West Bengal, India.
Horticultural Journal 6 : 7-13
Abstract : The physiological changes occurring in 'on' and 'off' cropping years of the irregular-bearing cultivars Langra and Himsagar and the regular-bearing cv. Baramasia were investigated using application of plant growth regulators to induce flowering. The chromatograms of stem extracts taken from all treatments and cultivars revealed a growth promoting zone between Rf 0.7 and 1.0 from trees sampled during Sep.-Oct. and 2 distinct inhibitor zones of Rf 0-0.3 and 0.4-0.6 from trees sampled during Sep. in the 'on' year. The concentration of inhibitor increased gradually from Sep. to Dec. The increase in Dec. was most pronounced with Ethrel [ethephon] treatment of all cultivars and MH [maleic hydrazide] treatment of Himsagar. The concentration of growth promoting substances present in Sep. was higher in the 'off' than in the 'on' year for Himsagar and Langra. Treatment with MH [maleic hydrazide] markedly reduced the amount of promoter and increased the inhibitor prior to flowering in Himsagar. Treatment of Langra with Ethrel or KNO3 increased the inhibitor during Nov., while there was little change in endogenous growth regulators in Baramasia.