Defoliation combined with exogenous ABA application results in slower ripening and improved anthocyanin profile
Reducing sugar accumulation in grape (Vitis vinifera L.) berries may be a way to mitigate the effect of climate change. Managing canopy and crop load is an effective way to do so, however, reducing canopy size has been demonstrated to induce undesirable effects on anthocyanins. The aim of this study was to test if an application of exogenous ABA on the grape berries of defoliated vines (⅔ of the leaves removed) can result in slower sugar accumulation while maintaining grape and wine quality. An experiment with defoliation and exogenous ABA application on directly on clusters (factorial design 2×2) was performed with ‘Tempranillo’ fruit-bearing cuttings. Defoliation reduced sugar accumulation and pH, while increasing titratable acidity. Grape anthocyanin concentration was reduced by defoliation but increased with the application of ABA. Musts fermenting for 14 days along with the skins and seeds showed a higher color intensity, higher free anthocyanin concentration and a more bluish HUE (A620/520nm) in defoliated plants with ABA. Leaves are necessary for carbon fixation, but also for the biosynthesis of ABA. Our results suggest that the combination of defoliation and exogenous ABA application results in slower ripening with better anthocyanin profile and improved color which is an interesting trait for aged wine production.
Acknowledgements: Authors thank J.F. Cibriain (EVENA) for providing the plant material to do the experiments and A. Urdiain, M. Oyarzun and H. Santesteban for excellent technical support. This study was funded by the “ANDIA talento senior 2021” (Gobierno de Navarra).
Issue: ICGWS 2023
1 Universidad de Navarra-BIOMA, Plant Stress Physiology Group (Associated Unit to CSIC, EEAD, Zaragoza). Irunlarrea 1, E-31008, Pamplona, Navarra.
2 Instituto de Agrobiotecnología (IdAB), CSIC-Gobierno de Navarra, Avda. de Pamplona 123, 31192 Mutilva, Navarra.