Impacts of sustained deficit irrigation on quality attributes and flavonoid composition of Shiraz grapes and wine.

摘要

Deficit irrigation of grapevines can influence canopy structure, berry size and composition, but how these changes affect wine quality is not well understood. In 2004, field trials were established in North West Victoria, Australia to explore the impact of sustained deficit irrigation on Vitis vinifera and the subsequent effects on the quality attributes and flavonoid composition of the grapes and wine. The trials were conducted on Shiraz grafted to 140 Ruggeri (V. berlandieri x V. rupestris) rootstock. The vines were drip irrigated providing 100% of estimated Et_c (control) and three graded sustained water deficits (65, 45 and 34% of the control). Assessments of grape composition were performed on whole berries to measure sugars, titratable acidity, pH, anthocyanins and phenolics. Micro-ferments were conducted on grapes collected at the 2005 harvest to assess wine colour density, wine hue, red pigments, anthocyanins, phenolics and co-pigmentation products in the wine. Initial findings indicate that wine made from the 45% treatment is producing higher wine colour density, total anthocyanins and total red pigments relative to the control. Overall, this work is part of a broader project that is seeking to understand the physiological basis for varietal differences in vine response to deficit irrigation and how these may impact on grape and wine composition.