Millerandage—One of the Grapevine Cultivation Challenges in the Climate Change Context

This study investigates millerandage, a physiological disorder affecting grapes during their development. In the climate change context, millerandage can become a viticultural hazard problem causing yield drops and posing challenges regarding wine quality due to uneven ripening in grape clusters. Using the 2023 vintage data from the Research Station for Viticulture and Enology Blaj (SCDVV Blaj), Târnave wine region, Romania, we assessed the climate conditions of 2023, focusing on the adverse climatic conditions from the flowering phenophase and the observed millerandage grade that occurred as a consequence. A total of 26 grapevine cultivars were monitored, assessing millerandage grade by field observations carried out in two grapevine plantations (S1 and S2) in July (BBCH 79) and September (BBCH 87). The results show statistically significant differences, with cultivars like Ezerfurtu (Ez), Napoca (Na), and Rhin Riesling (RR) exhibiting a millerandage grade higher than 35%, while cultivars like Pinot noir (PN) and Pinot gris (PG) showed resilience, with millerandage grades below 1%. These findings highlight cultivar-specific vulnerabilities and provides insights into millerandage’s role as a climate change challenge in viticulture.