Agronomic, physiological and qualitative response of white variety verdejo to irrigation and its management in the A.O. Rueda

Abstract

Irrigation management of white grape varieties has received less attention than the red varieties in Spain, having facing generally towards the increase of grape yield. The obvious existing water stress situations in many areas, in many cases aggravated by the situation of climate change, lead to the need to apply irrigation in white varieties, which must be consistent with a proper simultaneous management of other cultural techniques to achieve the objective of regulate the production and improve the quality of wine grapes in each viticultural zone.

During 2012, the application of moderate irrigation has been studied, with two different doses, through the following experimental treatments: rainfed (S00), 25% ETo (R25) and 50% ETo (R50), implemented from vegetative growth stop of main shoots until harvest. The trial has been developed with vines of cv. Verdejo on 110R rootstock, planted in 2006 and trellised as a Royat bilateral cordon. The vine distances were 2.60 m x 1.25 m (3,077 plants/ha). The study was conducted in a vineyard located in the A.O. Rueda, in Valladolid (Spain), focused on the evaluation of agronomic, physiological and qualitative response to two different doses of irrigation.

The preliminary results obtained have shown remarkable water, physiological and productive response to the amount of water applied, while vegetative growth has been aided by irrigation in comparison with the dry vines, but no major differences between the two irrigated treatments applied have been found. As for the quality of the grapes, the greater water stress suffered by rainfed treatment has caused an increase in levels of total acidity, tartaric acid and potassium with respect to the irrigated treatments. In contrast, there has been greater concentration of soluble solids and malic acid at the irrigated treatments than in the rainfed, especially in high dose of water, according to a situation of less water stress.