Impact of season, rootstock, and cultivar on chemical composition and volatile profiles of ‘Arinto’ and ‘Fernão Pires’ white wines from a tropical climate

New varieties and rootstocks adapted to tropical climates remain a challenge for improving wine production and quality, emphasising the need to optimise sensory characteristics and typicity. This study aimed to characterise the oenological potential of wines from the ‘Arinto’ and ‘Fernão Pires’ cultivars, grafted onto IAC 572 and 1103 Paulsen rootstocks, in a semiarid tropical region over four consecutive vintages (considering the first and second semesters). The impact of harvest season, rootstock, and cultivar on the chemical and volatile composition was evaluated to provide new insights into tropical wine typicity. Gas chromatography coupled with mass spectrometry (GC-MS) was used to quantify volatile compounds. The season of harvest was the most influential factor, followed by cultivar and rootstock. Wines produced from grapes harvested in the second semester of the year exhibited greater oenological potential, with higher concentrations of key volatile compounds, including ethyl esters, higher alcohol acetates, and terpenes. Principal Component Analysis (PCA) identified phenylethyl acetate, isoamyl acetate, linalool, ethyl propanoate, ethyl hexanoate, and ethyl octanoate as markers of wines from the second semester. Additionally, methyl geranate was detected for the first time, suggesting its potential as a typicity marker for these varieties. These findings reinforce the viability of ‘Arinto’ and ‘Fernão Pires’ for tropical wine production, providing valuable knowledge for viticultural strategies in emerging tropical winegrowing regions.