MODELLING THE EFFECT OF SOURCE/SINK MODIFICATIONS ON PULP DRY WEIGHT OF BANANA 'CAVENDISH'

The effects of source/sink factors on banana pulp dry weight during growth were modelled. The model simulates the increase in pulp dry weight according to the ratio of supply and demand for assimilates for pulp filling. The source/sink ratio was calculated as the ratio between the assimilates available for pulp filling and sink size, which was estimated by the number of cells in the bunch. An allometric relationship between the number of pulp cells, in fruit and fruit length at the end of cell division, was selected. A Michaelis-Menten relationship was used to simulate the cell filling rate in a bunch, with respect to the source/sink ratio during cell filling. To test the model, variations in the source/sink ratio in ‘Cavendish’ plants were obtained by decreasing sink size (by fruit pruning) before and after the end of cell division. Simulations of the different leaf-to-fruit ratio treatments showed good agreement with observed fruit growth data. The model was used to explore scenarios representing different cultivation practices (bunch trimming, leaf pruning) and effects of climatic conditions (temperature, solar radiation) usually observed in the French West Indies.