Project title
Berry tannin structure and phenolics evolution in cv. Cabernet Sauvignon (Vitis vinifera L.): effect of irrigation and canopy management

Project leader
Witbooi, E

Institution
University of Stellenbosch. Department of Viticulture and Enology.

Team members
Deloire, A
Richardo da Silva, JM
Nieuwoudt, H
Du Toit, W
Oberholster, A
van Zyl, A

Project description
Irrigation and canopy management are two practices which influences grape production (berry composition and yield). Warming of the climate is unequivocal and now evident from
observations of increases in global average air and ocean temperatures (IPCC, 2007). Many researches on climate change and viticulture have shown that cultivars have responded to the
observed warming with earlier phenological stages or dates of harvest and shortening of periods between phenological stages (Jones, 2006; Barbeau, 2007; Ramos, 2007; Chabin, et
al., 2007; Monany & Gueydon, 2007; Moncomble et al., 2007; Duchene & Schneider, 2007).
Global climate change in terms of increase in temperature and in evapo-transpiration will increase the vine water consumption. Due to the latter, irrigation will be a necessity and different irrigation strategies will have a direct influence on the berry and wine composition (Ojeda et al., 2002; Capraro et al., 2008).
The effect of the irrigation has been studied worldwide. Despite these studies there is still a great deal of uncertainty regarding irrigation and canopy management influence on tannins
structure and phenolics evolution. The objective of this study is to evaluate (i) how plant water status (in interaction with the canopy) influences the biosynthesis and the structure of tannins
and the evolution of other phenolics as anthocyanins and flavonols during the all berry growth period; (ii) how the evolution of these phenols will affect the wine composition and perception.

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