Rootstock and harvest season impact on the chemical composition of wines from portuguese and spanish clones of ‘Aragonez’ (syn. ‘Tempranillo’) cultivar (

Portuguese and Spanish clones from ‘Aragonez’ grapevine (syn. ‘Tempranillo’), although considered synonyms, exhibit distinct responses when combined with different rootstocks and harvest seasons under the tropical semi-arid climate of the São Francisco Valley, northeastern Brazil. This study evaluated the effects of four rootstocks (‘IAC313’, ‘IAC572’, ‘P1103/Paulsen’, and ‘SO4’) over four consecutive vintages, considering two harvests per year, on the yield and physicochemical composition of red wines. Wine composition was primarily influenced by harvest season, followed by clone origin and rootstock. Second-semester harvests promoted higher alcohol content, pigment levels, phenolic compounds, tanning power, and antioxidant capacity, whereas the 2016_1 harvest, under heavy rainfall, showed lower potential. Among rootstocks, ‘SO4’ was associated with higher flavonoid content, polymeric pigments, copigmentation, and antioxidant capacity, particularly in Spanish clones, although it showed lower yield in some semesters. In contrast, ‘IAC313’ maintained higher productivity, highlighting the importance of rootstock–clone interactions for vine performance in tropical regions. The predominance of polymeric tannins and high tanning power indicated wines with greater ageing potential and sensory complexity. Strong correlations between tannins, anthocyanins, and antioxidant capacity underlined the important role of phenolics in wine quality and bioactivity. Multivariate analysis showed that classical composition variables discriminated samples better than monomeric anthocyanin profiles. These results emphasize the need for adaptative viticultural and oenological strategies, such as harvest scheduling, informed rootstock selection, and tailored winemaking practices, to improve quality, productivity, and stability of tropical wines.