Evaluation of rootstocks for the ‘Verdejo Negro’ cultivar

Grapevine (Vitis vinifera L.) cultivation in Asturias (Northwestern Spain) was on the brink of extinction in the last century. Nevertheless, the present century is witnessing its rebound as a consequence of the recognition of the Cangas Wine Designation of Origin. The long period of abandonment has resulted in a lack of information about the most suitable rootstocks for the attainment of optimal quality. In this study, the agronomical and oenological parameters of the ‘Verdejo Negro’ cultivar grafted on three rootstocks (‘196-17 C’, ‘101-14 MG’ and ‘3309 C’) were studied. Three repetitions of ten vines for each rootstock were disposed in a completely randomized design. Agronomical (phenology, yield, pruning weight and Ravaz index) and enological (berry, must and wine composition) parameters were measured, and the elaborated wines were sensorially evaluated. Concerning phenology, the ‘101-14 MG’ rootstock advanced the veraison in the last two years of the study. The year significantly influenced many of the agronomical and enological parameters, whereas the rootstock only affected the Weaver index, which was higher for the ‘101-14 MG’ rootstock, indicating a more advanced maturation with this rootstock, and at the wine volatile acidity, higher for ‘3309 C’ wines. When the wines of ‘Verdejo Negro’ grafted on the three studied rootstocks were sensorially evaluated, few differences were found. Wines from ‘101-14 MG’ scored slightly better for nose parameters, although the overall judgment was very similar for all the wines. Considering the small effect of the rootstocks on the wines of ‘Verdejo Negro’, there is no clear recommendation at present. But it is important to take into account the effects of climate change, since the advance of maturation induced by the ‘101-14 MG’ rootstock may hinder the production of balanced wines of the ‘Verdejo Negro’ cultivar in the future. The predicted earlier ripening may lead to grapes with excessive sugar level, low acidity and a decoupling of phenolic and technological maturity.