ARCHITECTURAL APPROACH OF THE MECHANISMS OF CANOPY GROWTH AND FLOWERING OF MANGO TREES

Abstract

An alternate flowering and a low number of inflorescences at the time of the blossoming of the mango tree (#Mangifera indica# L.), are parts of the identified causes of a generally low yield of this tree (3 to 7 tons per hectare) in West Africa. A new approach based on the methodological support of the architectural analysis has been considered to try to resolve these problems. A better understanding of the structure and the functioning of a plant, throught a descriptive and functional study of its components, whose the arrangement is the expression of endogenous and exogenous factors, is choosen. Applied to mango seedlings, the architectural analysis allowed to identify and characterize five types of axes. One is very interesting on a level with sexuality. It concerns the delayed proleptic axes defined as DRA's because of their reiterative origin, which have the particularity tobear more than 60 % of the production of a tree, though they represent only 30 to 40 % of the twigs. These axes have an important sexual function, even though the others have a function orientated towards the vegetative development of the tree. The parting in space (position iin the tree), and in time (different functionning) of the activity of the meristems corresponds to specific functions of reiterated complexes. It squares with a reiterative strategy of mango tree. The alternate bearing and the erratism appear as the expression of particular functionings of these meristems, and neither as aberrations of flowering and vegetative mechanisms. The types of axes and the general organization of mango in three subunits allow to consider agronomic practices to increase the yield of grafted mango trees