QualiTree, a virtual fruit tree to study the management of fruit quality. I. Model development

This article presents QualiTree, a generic fruit tree model that can simulate the effects of various cultivation practices on the development and within-tree variability of fruit quality. These practices include fruit thinning, summer and winter pruning, irrigation and tree training. Combining both agronomic and physiology viewpoints, the model describes the tree as a set of objects-fruiting units organised into a tree architecture and viewed in detail, and other compartments viewed globally-that exchange carbon and are the targets of physiological functions that can be changed by cultivation practices. The complex effect of shoot removal on tree behaviour was subjected to a special modelling effort using the coordination theory. QualiTree combines existing models of fruit quality development and simple carbon allocation functions. Though parsimonious, it is able to express a high degree of variability of fruit quality criteria. Future developments of QualiTree relative to an extension of the range of fruit quality criteria and the effects of cultivation practices are also discussed.