EFFECTS OF THE IRRIGATION REGIME ON WATER RELATIONS OF A TABLE GRAPE AND TWO WINE GRAPE CULTIVARS IN A SEMIARID REGION OF VENEZUELA

The effect of different irrigation regimes on water relations of a flood irrigated table grape (‘Italia’) and two drip irrigated wine grape varieties (‘Chenin blanc’ and ‘Semillon’) was evaluated in two vineyards of a semi-arid region of Lara state, Venezuela.
Well irrigated plants were kept at 10–20% soil water depletion for table grapes and 0,4 crop evaporation factor for wine grapes, whereas stressed plants were brought close to permanent wilting point (PWP) in the top 40–60 cm for table grapes and 0.1 crop factor for wine grapes.
Predawn leaf water potentials (LWP) in table grapes were -0.20 vs. -0,45 MPa for well irrigated vs. stressed vines, respectively.
LWP averaged -0.27 vs -0.40 MPa in ‘Chenin blanc’ and -0.43 vs -0.53 MPa in ‘Semillon’ for well irrigated vs. stressed plants.
At 2 p.m. stomatal resistance ranged between 1.0 and 1.5 s/cm in non stressed vs. 5.0 s/cm in stressed ‘Italia’ plants.
Photosynthesis rates ranged from 14.37 to 10.70 μmol/m²/s in ‘Semillon’ for well irrigated and stressed plants, respectively.
The paper emphasizes how some physiological parameters are affected in poorly irrigated grapevines.

I ISHS Workshop on Water Relations of Grapevines

R. Pire, M. Ojeda

Grapevine, Vitis vinifera, water stress, leaf water potential, photosynthesis, stomatal resistance

https://doi.org/10.17660/ActaHortic.1999.493.9