A Model of Grape Growth and Development: the Mathematical Structure and Biological Considerations1

Abstract

A mathematical age structure model for dry matter production (photosynthesis) and allocation to plant parts in European grape (Vitis vinifera L.) is presented, and it is used to examine the priorities and allocation dynamics of photosynthate partitioning to respiration, reserves, leaf, stem and root tissues (i.e., vegetative), and fruit in four varieties. In the model, photosynthate is allocated first to respiration, then fruit and reserves, and lastly to vegetative growth, while the allocation rates are controlled by the ratio of photosynthate supply to the various demands at the successive priority levels. Maximum and minimum temperatures are used to compute physiological time and physiological age in the model (i.e., in degree days above 10 °C), while solar radiation (Jm−2 day−1) is used to compute the per unit leaf rate of photosynthesis. Extensive field data on dry matter allocation for the variety Chenin blanc were used to construct and validate the model, while smaller data sets were used to estimate parameters for three other varieties of grape. The model results simulate well the observed data.