Phenolic composition of Aglianico and Nero di Troia grapes and wines as affected by cover cropping and irrigation

The aim of this study was to evaluate over two seasons (2007 and 2008) the effect of cover cropping and irrigation on the phenolic composition of grapes from two red cultivars (Aglianico and Nero di Troia) grown in Southern Italy and of their corresponding wines. Cover cropping led to impoverishment in phenols of grapes and wines of Aglianico and to enrichment of Nero di Troia. For both varieties irrigation deficit led to higher contents of anthocyanins and total polyphenols, indicating that their concentration is closely related to water stress intensity. Some differences were found according to season: Aglianico grapes and wines produced in 2008 were richer in phenols than those produced in 2007, whereas an opposite trend was observed for Nero di Troia. The study demonstrated that the application of modulated water stress to the investigated cultivars allows one to obtain wines very rich in phenolic substances, thus improving the wine quality.