|BOWEN, PAT - Pacific Agri-Food Research Center|
Submitted to: American Society of Enology and Viticulture Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2012
Publication Date: 6/18/2012
Citation: Shellie, K., Bowen, P. 2012. Berry composition and yield of Cabernet Sauvignon and Malbec in response to water deficit severity. American Society of Enology and Viticulture Annual Meeting Abstracts. 63rd ASEV Technical Abstracts/ pg. 148-149..
Technical Abstract: Water supply is a production tool used in arid climates to elicit desirable, water-deficit related changes in berry composition and yield; however, response to water deficit is known to vary by cultivar. The objectives of this research were to determine whether cultivars differed in their relationship between water supply and water deficit and whether this relationship was associated with differences in yield and berry composition in response to reduced water supply. Drip-irrigated, own-rooted Cabernet Sauvignon and Malbec grapevines were maintained under differing severities of water deficit over four seasons by supplying 70 or 23% of estimated crop evapotranspiration throughout berry development. Both grape cultivars produced ripe fruit under reduced water supply; however, Cabernet Sauvignon exhibited more severe water stress, greater yield reduction and less increase in berry, anthocyanins and total phenolics than Malbec under similar water supply. Pre-dawn and midday leaf water potential were similarly related in both cultivars; however, contrasting relationships between midday leaf water potential, stomatal conductance and soil moisture revealed differences in cultivar physiological response to drought. The physiological adaptations of these cultivars to sustained water deficit revealed a combination of drought avoidance (stomatal regulation) and drought tolerance (reduced vegetative growth). Under the arid conditions of this study, optimum yield and berry composition were achieved in Cabernet Sauvignon under less severe water stress relative to Malbec. Results from this research present new information about cultivar differences in response to drought and its relationship with berry composition and yield and practical information for optimizing irrigation strategies for these cultivars under arid conditions.