LAUSR

The effects of three irrigation levels (two regulated deficit irrigation treatments [RDI] at 25% and 50% replacement of water loss through crop evapotranspiration [ETc] and 100% ETc) combined with three timings of irrigation initiation (fruit set [FS], lag phase [LP], or veraison [VRN]) on grapes and wines of the French-American hybrid Baco noir were studied in Ontario, Canada. Berry composition varied from vintage to vintage. The highest total soluble solids (TSS; Brix) values were measured in 2005 and 2007. In 2005, RDI treatments applied at LP increased Brix, while in 2007 similar results were obtained in VRN-applied treatments. Berry TA increased slightly in irrigated treatments compared to the control in each season. Berry pH was lowest in 2005 and highest in 2006 and 2007. Berries from LP-applied RDI treatments had higher pH or were similar to the control, while berries from VRN-applied RDI treatments had lower pH. Anthocyanins and total phenols in berries increased in almost all irrigated treatments in 2005, while in 2006 and 2007, the highest concentrations were found in berries from LP treatments. Multivariate analyses showed that soil and plant water status correlated well with typical descriptors for Baco noir wines. The highest intensities of flavor and aroma attributes were associated with 50% and 25% ETc levels applied at LP or VRN. Principal components analysis indicated that severe water deficit could negatively affect the varietal aroma profile. The sensory profiles showed that wines could be manipulated by RDI strategy, but vintage variation indicated that other factors related to grape microclimate could have also been involved.