Foliar applied potassium nitrate found to induce bud break of quiescent pre-existing floral buds in mango

The exact mechanism of foliar applied potassium nitrate in mango on bud dormancy break is still not fully understood. A flower intensity index of 4 (flowers all over the canopy) and longer inflorescences in paclobutrazol (PBZ) treated trees was a result of induction of flower bud break by 2% KNO3 sprays, while control trees exhibited a flower intensity index of 2 (less than 25% of the canopy have flowers). PBZ treated trees showed 12,3% longer panicles and 67% higher fruit retention (Table 1).

Mango shoots must have low gibberellic acid (GA) content to allow total non-structural carbohydrates, primarily starch, to accumulate in the leaves and buds, leading to the early formation of floral initials. Potassium nitrate induces bud break of quiescent pre-existing floral buds and is not responsible for the transformation of vegetative buds to reproductive ones, because floral initials were present before KNO3 application.

Table 1. Effect of paclobutrazol (at 1 g of PBZ per meter canopy diameter) treatment on the intensity of flowering and retention of fruits in KNO3-sprayed ‘Carabao’ mango trees.

 

Author

Serrano, E. P., I.P. Marquez, F.M. Rodriguez, C.M. Protacio and J.E. Quinto. 2006. Unravelling the mechanism of mango flowering. Acta Horticulturae VIII International Mango Symposium 820: 259-270.

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