Berry tannin structure and evolution in cv. Cabernet Sauvignon (Vitis vinifera L.): the contribution of abiotic factors (light and temperature)

Project Number
WW EW 10-02

Project title
Berry tannin structure and evolution in cv. Cabernet Sauvignon (Vitis vinifera L.): the contribution of abiotic factors (light and temperature)

Project leader
Blancquaert, E

University of Stellenbosch. Department of AgriSciences. Department of Viticulture and Oenology

Team members
Deloire, A
Richardo da Silva, J M
Nieuwoudt, H H
Du Toit, W J
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 researchers 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 .

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.

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: 1. 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 2. how the evolution of these phenols will affect the wine composition and perception

Witbooi, E. 2010. Cutting the Gordian knot: Using science to simplify the complexities of berry ripening. Lecture. University of Stellenbosch, AgriScience Faculty Science Day. 1 December, Stellenbosch, South Africa.

Blancquaert, E H, Oberholster, A, Ricardo da-Silva, J M and Deloire, A J. 2010. Berry ripening and bunch microclimate: Preliminary results on Cabernet Sauvignon. Presentation at the Robertson Optimal Ripeness Day. October, Robertson, South Africa.

Witbooi, E. 2011. Sensorial perception of wines made from grapes at two berry sugar loading stages. Paper presented at the Oeno 2011: 9th International Symposium of Enology. 15-16 June, Bordeaux, France.

Arnold, R. 1980. Bitterness and astringency of phenolic fractions in wine, Journal of Agricultural and Food Chemistry, v. 28 (3) (p. 675-678)

Bieza, K, Rodrigo, L. 2001. An arabidopsis mutant tolerant of lethal ultraviolet B levels shows constitutively elevated accumulation of flavonoids and other phenols, Plant Physiology, v. 126 (31) (p. 1105-1115)


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