Macabeo (Viura) grape response to climate variability in areas located at different elevations in the Rioja Designation of Origin.

Background: This research aims to analyse the influence of climatic conditions on phenology and grape composition of Macabeo, which is one of the white varieties authorized in Rioja DOCa. Phenological dates for flowers separated and harvest, and grape composition were evaluated for the period 2008-2020 in five plots, located at different elevations (457-650 m a.s.l.). Grape parameters were related to temperature and water deficit recorded along the growing cycle.

Results: High variability in the weather conditions were recorded during the period analysed, with differences in the average growing season maximum temperature of up to 2.5 °C among years and about 2 °C among locations. Differences in the average growing season precipitation of about 200 mm among years and up to 60 mm among locations were recorded. That high variability could explain the differences in grape composition observed among years and among zones. The lowest sugar contents were recorded at the highest elevation, while acidity in that area was the highest. Although the relationship was only significant in one plot, probable volumetric alcoholic degree increased with increasing maximum temperature. Titratable acidity and malic acid decreased with increasing maximum temperature, the change being higher in the plots located at the highest elevation. Both titratable acidity and malic acid were significantly affected by water deficits recorded during the growing season, and in particular that recorded after floowering.

Conclusion: The results indicate that under warmer scenarios a decrease in titratable acidity and in malic acid might be expected for this variety, but with differences among zones located at different elevations. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.