The relevance of grapevine varietal diversity for the adaptation of organic viticulture to climate change

Autochthonous varieties are often the best-adapted genotypes to their local environments. In viticulture, this makes local cultivars particularly suitable for organic systems and enables growers to produce wines with a strong identity linked to local traditions and regional char-acter. However, PDO and PGI appellations (DOC, DOCG, and IGT in Italy) were defined based on the most suitable varieties identified in the second half of the 20th century, under environmental conditions that differ substantially from today’s. Within the framework of the ValorInVitis and SalViBio projects, 28 underrepresented local grapevine cultivars were evaluated over six years (2017–2022) in the Colli Piacentini area. The locally widespread grape varieties Ortrugo (white) and Barbera (red) were used for con-trol purposes i.e. sensory and wine chemical comparison. Among the genotypes assessed, Barbesino emerged as the variety maintaining the highest grape titratable acidity, a key trait for white and sparkling wine production, and therefore may have compensatory potential for Ortrugo, which is prone to comparatively strong malic acid degradation at elevated average temperatures. Molinelli was identified as one of the least susceptible to bunch rot, thanks to its loose cluster architecture and thick berry skin. Dura-guzza stood out among red cultivars for its high anthocyanin concentration and skin thick-ness, conferring tolerance to both sunburn and bunch rot. Ervi showed the most promising enological profile among the red varieties, due to high phenolics and sugars accumulation. Malvasia Rosa displayed the rare combination of a pink berry color and geraniol-based ar-omatic terpenes. Lisöra exhibited early ripening and good tolerance to downy and powdery mildew, making it particularly suitable for cooler, upland areas. Currently, local growers are considering including Ervi in the Gutturnio DOC red wine appel-lation, while Barbesino and Malvasia Rosa are already cultivated more widely. In collabora-tion with growers’ associations, the process for the registration of Molinelli and Lisöra in the national and regional lists of cultivable varieties is ongoing.