The characterization of the plant is the obliged pathway between the environment and the product. The responses of the plant amplify or reduce the variations of the environment, while determining directly the type and the quality of the products. These results are inscribed inside the Viticultural Terroir Unit (VTU). VTU is the complex interaction between the Basic Terroir Unit or BTU (interaction mesoclimate x soil/subsoil), the genotype (variety x rootstock), the management system, the oenological technologies. Thus, at the most complex level, a global biological triptych is found again : environment (source) x plant (structure) = produced and exchanged substances.
It is important to note that the management system, resulting from the technical choices of the grower, generally acts on the environmental factors themselves, such as radiation, temperature, water and mineral element flux. Therefore, on one hand the study at the level of the plant is necessary to establish an objective link between the environment and the product, and on the other the observations in the plant concern the same variables as for the environment ; the zoning methods related to the plant must be associated to those concerning the environment, for a precise production.
Author: Alain CARBONNEAU
Chaire de Viticulture et d’œnologie AGRO Montpellier
2 place P. Viala F-34060 Montpellier cedex