Influenza dei fattori dell’ambiente sulla risposta della pianta, e caratteristiche dell’uva della cv tannat prodotta in vigneti di tre zone climatiche dell’Uruguay

Grape typicity valorization can significantly enhance viticultural sector competitiveness to the extent that contributes to the development of a wine so distinctive and unique. This work leads to the characterization of the grapes through indicators expressing environmental effects. This research was carried out during 2008 and 2009 in 4 Tannat cultivar vineyards, in 3 different climatic regions of Uruguay; soil water reserve capacity was similar. By means of climate data, and berry composition and physiological plant response indicators analysis, it was established which were the most influential variables giving specificity and potential of wine in each production area. Climatic factors allowing discrimination of those areas were: water balance during berry ripening, rain amount by crop phoenological stages, degree days during ripening. Referring to plant response: exposed leaf surface and ripening phase duration (in Julian days) were the most important factors followed by predawn leaf water potential at flowering phase, and berry yield. With regard to berry composition the most important factors were sugars and malic acid contents followed by anthocyanic potential and tartaric acid content. These factors could statistically separate the grape growing areas independently of the year effect. We conclude that plant response and berry composition were strongly influenced by the environment. From this the main factors were water supply and temperature during ripening phase.