Timing of defoliation affects anthocyanin and sugar decoupling in Grenache variety growing in warm seasons

• DOI: 10.1016/j.jfca.2023.105729
• Publication Date: 2023-09-30T20:36:32Z
• Authors: Purificación Fern...; Luis Gonzaga Sant...; Ana Villa-Llop; Maite Loidi; Carlos Peñalosa; Sergio Musquiz; Nazareth Torres
• Keywords: Veraison; Growing season

Warming trends over the winegrowing regions lead to an advance of grapevine phenology, decreased yield and increased sugar content with a lower polyphenol content. We hypothesized that different leaf removal timings may counteract these effects. A two-year experiment was conducted in La Rioja (Spain) Vitis vinifera L. cv. Grenache trained open-vase system. Trial consisted complete block design two treatments differing moment manipulation: i) severe treatment after fruit set (ELR); ii) at veraison (LLR) compared untreated control (Control). Both tended decrease no effect on yield, effects being highly affected by year. Defoliation accounted for flavanol stilbene contents berries harvest. An ELR anthocyanin phenolic acid harvest, while warming during 2022 all monitored groups flavonols. only effective delaying ripening means impairing sugar:anthocyanin decoupling 2021 growing season which related % kaempferol. Altogether, results suggested defoliation should still be applied under currently some viticulture regions.