Effects of future climate change on grape quality: a case study for the Aglianico grape in Campania region, Italy

Water deficits limit yields and this is one of the negative aspects of climate change. However, this applies particularly when emphasis is on biomass production (e.g. for crops like maize, wheat, etc.) but not necessarily for plants where quality, not quantity is most relevant. For grapevine water stress occurring during specific phenological phases is an important factor when producing good quality wines. It induces in the red wine the production of anthocyanins and aroma precursors. On this base, in some terroirs the future climate constrictions could represent an opportunity to increase winegrowers’ incomes.

This study was carried out in Campania region (Southern Italy), an area well known for high quality wine production. Growth of the Aglianico grapevine cultivar, with a standard clone population on 1103 Paulsen rootstocks, was studied on two different types of soil: Calcisols and Cambisols. The agro-hydrological model SWAP was calibrated and applied to estimate soil-plant water status at the various crop phenological phases for three vintages (2011-2013). Then, the Crop water stress index (CWSI), as estimated by the model, was related to physiological measurements (e.g. leaf water potential), grape bunches measurements (e.g. sugar content) and wine quality (e.g. tannins). For both soils, the correlation between grape quality characteristics and CWSI were high (e.g. 0.895 with anthocyanins in the skins).

Finally, the model was applied to future climate conditions (2021-2051) obtained from statistical downscaling of Global Circulation Models (AOGCM) in order to estimate the effect of the climate on CWSI and hence on grape quality. Results show that in the study area the effects of climate change on grape and wine quality are not expected to be significant for Aglianico grapevine when grown on Calcisols and Cambisols.