Biodiversity in Grapevines: Unveiling the Potential of Ancient Sicilian Cultivars and Biotypes of Key Indigenous Varieties

The biodiversity of grapevines, crucial for viticulture, encompasses over 10,000 cultivars listed in the International Catalogue of Grapevine Varieties (VIVC). This diversity, categorized into biotypes and clones, gives rise to intra-varietal variations, ranging from minor morphological changes to macroscopic alterations, influencing adaptability and wine quality. Historical factors, such as the 19th-century Phylloxera epidemic in Europe, resulted in the dominance of a limited number of Vitis vinifera L. genotypes. However, renewed interest in ancient local cultivars and biotypes has emerged due to pressures linked to climate change. Intra-varietal diversity is now recognized for its potential to maintain grape quality under adverse climatic conditions. In 2023, the agronomic potential of ancient Sicilian varieties (Lucignola and Vitrarolo) and the biotypes of the main indigenous cultivars (Grillo, Catarratto, Nero d'Avola, Perricone, Frappato, Nocera) was assessed in four experimental vineyards located in different regions of Sicily (Western, Central, and Eastern). The study assessed the "genotype x environment" interactions, comparing biotypes regardless of the environment. The genotypes shared the same spacing, training system, and pruning method, under irrigation. Ten vines were chosen randomly for each genotype, serving as biological replicates. Phenological stages, recorded independently for each vine, represented the percentage of buds at each stage. For each genotype, the progress of grape ripening, berry weight, vegetative growth, and water status were evaluated. At harvest, the yield per vine and the number of bunches were recorded, and their ratio was used to calculate the average bunch weight. During winter, the pruning wood weight was measured and the Ravaz index was calculated. Our results show that grape ripening depends on environmental conditions, and vines show different water status levels. Lesser-used grape genotypes may hold promise for adapting to climate change, serving as tools for preserving typical grape characteristics, but is needed further investigation.