The quality of 'Fortune' mandarin fruit ( Citrus clementine Hort. Ex. Tanaka * C. reticulate Blanco) subjected to four different drip irrigation treatments was studied at harvest and after a subsequent storage period of 50 days at 5degreesC plus a shelf-life period of 8 days at 20degreesC. Irrigation treatments consisted of a control (CTL) irrigated at 130% of crop evapotranspiration (ETc) throughout the season, and three regulated deficit irrigation (RDI) regimes. These treatments were irrigated as a CTL except during the non critical periods, when different percentage of the control were applied: 50% during stage I and beginning of stage II in RDI 1 and RDI 2 treatments, and 80 and 200% during stage III in RDI 1 and RDI 2, respectively. RDI 3 was irrigated at 50% of RDI 1 during the water deficit periods. The electrical conductivity of the irrigation water averaged 4.23 dS m -1. RDI treatments promoted a water stress integral, derived from stem water potential at midday values, of 56, 46 and 114 MPa day for RDI 1, RDI 2 and RDI 3, respectively. Fruit at harvest from RDI1 and RDI 3 treatments showed around 15% higher total soluble solids and 11 and 19% higher levels of titratable acidity, respectively than CTL (13.8degreesBrix and 20.3 g L -1 citric acid). RDI fruits showed about 5-10% lower values of extractable juice than control. The storage period reduced fruit titratable acidity compared with harvest levels. Weight loss in control fruit reached 1.4 or 2.3% w/w at the end of cold storage or shelf-life, respectively, while in RDI treatments were reduced by 0.2-0.4% w/w. Overall, the effect of water stress on fruit quality were more pronounced at harvest than after the postharvest treatments. Under water scarcity conditions RDI1 showed acceptable fruit quality at harvest and increased storability of mandarin fruit, saving considerable amounts of water.
