A VIRTUAL FRUIT MODEL THAT STRESSES QUALITY TRAITS

Fruit quality is a multi-criteria concept which is difficult to consider in modelling. Though all the processes involved in fruit quality cannot be integrated in biological models, a high degree of complexity is required to consider the effects of environment on quality. We are just beginning to investigate this complexity. A virtual fruit model that predicts the seasonal changes of several quality traits as influenced by early fruit growth, water status and leaf-to-fruit ratio, is presented. Assessed quality traits were fruit size, flesh content in the total mass, dry matter content of the flesh, flesh sweetness, and density of cuticular cracks. The virtual fruit model was developed by adapting and connecting existing models describing fruit growth in dry and fresh mass, sugar accumulation in the flesh and development of cuticular cracks. The model was adapted to late-maturing peach cultivars. Virtual experiments were carried out to analyse the effect of changing fruit size at the time of thinning, plant water status and leaf-to-fruit ratio on fruit quality and cracking. The virtual fruit model was able to produce complex behaviours resulting from changes in leaf-to-fruit ratio or water potential. Our results give possible interpretations about adaptation of plants to stresses. The prospective uses of the virtual fruit model are presented, as well as the opportunities that such a model offers for genetic and agronomic studies.