X. Choné1*, O. Tregoat1, C. van Leeuwen1, 2 et D. Dubourdieu1
1Faculté d'Œnologie de Bordeaux, Université Bordeaux 2 Victor Ségalen,
351 cours de la Libération, 33405 Talence cedex, France
2ENITA de Bordeaux, 1 cours du Général de Gaulle, 33175 Gradignan cedex, France
3INRA de la Grande Ferrade, 71 av. Edouard Bourleau, 33140 Villenave d’Ornon, France.
Abstract : Vine water status is an important factor in grape quality. High tannin and anthocyanin content in red grape berries are related to moderate vine water deficits. Hence, a simple and sensitive indicator is required to determine vine water status and especially water constraint. Pressure chamber allows a quick and easy to practice determination of water status in the vineyard. Three applications of pressure chamber are known: predawn leaf water potential (YB), leaf water potential (YF) and stem water potential (YT). Only YB and YF are widely used on vines. In this survey YB, YF, YT and transpiration flow were measured on mature leaves to determine non-irrigated vine water status in field grown vines during the growing season. In California as well as in France, stem Y was the most discriminating indicator for both moderate and severe water deficits. In every plot surveyed YT was much better correlated to leaf transpiration than YF. Moreover, YT revealed nascent water deficit earlier than YB did. Among the three application of pressure chamber, YT was the only one to indicate short term water deficit after a rainfall. Hence, YT appears to be a useful indicator for grapevine management in both non-irrigated and irrigated vineyards.
Key words : vine, terroir, water deficit, stem water potential, leaf water potential, transpiration.
*Correspondence : k-van-leeuwen@enitab.fr