Effects of paclobutrazol (PBZ) on floral induction and associated hormonal and metabolic changes of biennially bearing mango (Mangifera indica L.) cultivars during off year.
Rahim A. O. S. A., Elaminand O. M., Bangerth F. K.
Author Affiliation: Agricultural Research Corporation, Wad Medani, Sudan.
Journal of Agricultural and Biological Science 6 : 55-67
Abstract : The physiology of floral induction in mango is still controversial and thus further work is needed for a better understanding of reproductive physiology of this important fruit tree. The objectives of this study were to investigate the role of a gibberellins biosynthesis inhibitor, paclobutrazol on floral induction of biennially bearing mango during off year and to examine the possible correlated hormonal and non-structural carbohydrate changes. Three distinctly biennially bearing mango cultivars were tested for two years under North Sudan climates. Results indicated the advantage of paclobutrazol on inducing flowering of the biennially bearing mango cultivars, Miska, Mahmoudi, and Totocombo during off year. Similar trends of hormonal changes were observed during the floral induction period on the tested cultivars. More-specifically, the levels of cytokinins (zeatin (z) + zeatin riboside (zr) and isopentenyl Adenosine (i-Ado) + isopentenyl Adenine (i-Ade)), and to a less extent the levels of abscisic acid (ABA) generally showed trends of increase during the floral induction period, while those of gibberellins (GA1+3+20) and auxin (IAA) were decreased during the same period. Starch levels in most of the cases were increased by the paclobutrazol treatment. Moreover, sucrose levels were generally increased during the floral induction period. To close, possible roles for some of the tested hormones and non-structural carbohydrates on mango flowering are probably implicated.