Effects of irrigation on water relations, vegetative growth, yeld and fruit quality on field-grown grapevines (Vitis Vinifera L.)

Doutoramento em Engenharia Agronómica - Instituto Superior de AgronomiaThe present study had the main objective to understand the role developed by water availability in the vine ecophysiology, microclimate, berry quality and yield. This study was carried out in a commercial vineyard at the Centro Experimental de Pegões in the Moscatel and Castelão varieties. The effects of different water treatments in the physiological and agronomical vine parameters were studied. Deficit irrigation treatments, namely the partial rootzone drying (PRD) and deficit irrigation (DI), both with 50% ETc, induced mild water deficits during the ripening period, while FI plants (100% ETc) remained with a high predawn water potential in that period and non-irrigated vines (NI) showed a severe water stress. In PRD treatment we observed an important reduction on vegetative growth compared to DI and FI leading to more open canopies with higher values of radiation and berry temperature comparatively to the other irrigated treatments. PRD and NI showed the highest anthocyanins and phenols accumulation in berries, although no differences in berry sugar accumulation were found between treatments. As a result of the 50 % reduction in the amount of water applied without any significant yield reduction, water use efficiency was double in PRD and DI treatments when compared to FI