Libro de Actas - X Simposium Hispano Português de Relaciones Hidricas, 2010Deficit irrigation techniques, implying that water is supplied at levels below full crop evapotranspiration
throughout the growing season or in specific phenological stages, such as regulated deficit irrigation
(RDI) or partial root drying (PRD), emerged as potential strategies to increase water savings with
marginal decreases of yield and likely positive impact on fruit quality. Understanding the physiological
and molecular bases for plant responses to mild to moderate water deficits is of utmost importance to
modulate the appropriate balance between vegetative and reproductive development, to improve crop
water-use efficiency and to control fruit quality. It is acknowledged that the timing and intensity of the
response to soil and atmospheric water deficits, namely in what concerns stomatal control, depends
greatly on the genotype. This has profound implications in irrigation management, in particular the
timing and amount of irrigation to optimize source-sink relationships and achieve optimal fruit quality in
each variety. Mild water deficits also exert direct and/or indirect (via the light environment in the cluster
zone) effects on berry development and composition. A current research challenge is determining how
the environment, in particular water deficits, regulates genes and proteins of the various metabolic
pathways responsible for berry composition and therefore for wine qualit
