Effect of paclobutrazol on source-sink relationship in mango (Mangifera indica L.).

R.M. Kurian, Y.T.N. Reddy, R.K. Sonkar and V.V.P. Reddy

Division of Fruit Crops, Indian Institute of Horticultural Research, Hessaraghatta Lake Post, Bangalore - 560 089, India.

DOI: https://doi.org/10.37855/jah.2001.v03i02.06

Key words: cultivars, fruits, leaf area, leaves, mangoes, paclobutrazol, photosynthates, plant growth regulators, ringing, source sink relations, translocation
Abstract: The effects of paclobutrazol on the fruit-leaf ratio of twelve-year-old trees of mango cultivars Alphonso and Dashehari were studied in Bangalore, Karnataka, India. The soil was drenched with paclobutrazol at 0.0, 2.5, or 7.5 g a.i. per tree. In each paclobutrazol-treated tree, photosynthate and metabolite translocation to 30 leaves with a single fruit was inhibited by girdling the branch (1 cm wide ring of bark) at a uniform distance from the fruit. Girdling was conducted when Dashehari fruits were 4.9+or-0.7 cm long and weighed 27.9+or-8.5 g, and when Alphonso fruits were 4.0+or-1.0 cm long and weighed 32.9+or-7.5 g. Twenty-eight fruits on ungirdled shoots of trees not treated with paclobutrazol served as the control. In the two cultivars, thirty leaves were not sufficient to promote the growth of a single fruit, especially when the tree was not treated with paclobutrazol. In untreated trees, the weight of fruits from girdled trees of Alphonso and Dashehari was only 60.2 and 64.9%, respectively, of the cont



Journal of Applied Horticulture