Young flush thinning in Mango (cv. Cogshall) controls canopy density and production

Although mango has been grown for a very long time and cultivation is increasing, productivity is still low and irregular. In this work, we took up the common hypotheses in which fruiting under hot subtropical conditions competes strongly for limited carbon resources, and the strategy of the mango tree is to adjust carbon investment between the fruit and vegetative compartments. If flowering is too abundant for mango tree, the assimilates produced by photosynthesis will not fit the demand during fruit set and growth. However, rather than favouring vegetative development by heading cuts, we decreased the number of vegetative flushes (physiological sinks) by thinning cuts of young flushes as soon as they appear in order to improve their development and to increase flower induction in their terminal bud. In Reunion Island, we developed a young flush thinning cut protocol which aimed at optimising, at mango tree level, the source/sink relationships for carbohydrates with the objective to increase total yield and mango quality. The pruning method involved the removal of young yellow coloured twigs as soon as they appeared at each flush period. This one-year trial showed that the yield of treated trees was similar to that of control trees but individual fruit weight was greater. Moreover, some fruiting sites were stimulated and overall tree functioning was more homogeneous, in terms of phenology and successions of flushes. The pruned trees set delayed vegetative flush that led to delayed flowering and by consequence to delayed fruit maturation and harvest. This thinning cut of young flushes decreased canopy density, with limited branching. These results could bring about the development of new orchard management practices leading to orientated production of good standard quality mangoes. Ongoing studies aim at adapting this thinning cut procedure to other cultivars in various sites. (Résumé d'auteur