Orchard cooling with overtree sprinkler irrigation to improve fruit color of 'Delicious' apples

The influence of supplemental sprinkler irrigation on fruit color of 'Orego n Spur Delicious' (Trumdor) apples (Malus xdomestica Borkh.) was evaluated in the area of Lleida (NE Spain) over a 3-year period. Cooling irrigation w as applied for 2 hours daily for 25-30 days preceding the harvest. Three tr eatments were evaluated: 1) control without overtree sprinkler irrigation; 2) sprinkler irrigation applied at midday; and 3) sprinkler irrigation appl ied at sunset. Fruit color was significantly affected by the cooling irriga tion and also by the weather of the particular year. Increased fed color an d higher anthocyanin content resulted from sprinkler irrigation, especially when applied at sunset. At harvest, anthocyanin content was correlated wit h a*/b* and hue angle, suggesting that the colorimeter measurements could p rovide a nondestructive estimate of anthocyanin content.