Apical leaf removal differently modulates grape quality according to the application timing and vine water status.

BACKGROUND

Delaying grape ripening is a proposed strategy to mitigate the detrimental effects of climate change on grape quality. Apical leaf removal has been identified as a reliable technique to preserve berry quality in this context, although different application timings and vine water status may lead to divergent outcomes. This study aimed to disentangle the effects of apical leaf removal applied before the onset of veraison (early leaf removal (ELR)) and during berry ripening (late leaf removal (LLR), 16 °Brix) on grape quality parameters of Sangiovese grapevines subjected to full irrigation (well-watered (WW) vines) or water deficit (WD) conditions.

RESULTS

ELR and LLR delayed harvest date, decreasing berry titratable acidity but not influencing pH. ELR reduced anthocyanin accumulation and altered their hydroxylation patterns, whereas water deficit enhanced the accumulation of both flavonols and anthocyanins. ELR berries had the highest concentration of free volatile organic compounds (VOCs), but glycosylated VOCs were 17.3% lower than in the untreated control under WW conditions only. In contrast, LLR did not significantly affect anthocyanin concentration and enhanced glycosylated VOCs (by 22.6%, average between irrigation regimes).

CONCLUSION

Our findings indicate that application timing and vine water status can modulate the effects of apical leaf removal on the ripening delay and the berry quality traits. © 2026 Society of Chemical Industry.