Combined use of leaf removal and natural shading to delay grape ripening in Manto negro (Vitis vinifera L.) under deficit irrigation
The increasingly frequent heat waves during grape ripening pose challenges for premium wine grape production. This makes the development of irrigation and canopy management techniques of great importance to maximize yield and grape quality. A field experiment was carried out during 2021 and 2022 using Manto negro wine grapes to study the effect of two irrigation strategies and different light exposure levels on grape quality. Two irrigation treatments were imposed (moderate and severe deficit irrigation) in a four-block experimental vineyard at Bodega Ribas (Mallorca). Three light exposure treatments were randomly applied in each irrigation plot. The light treatments included exposed clusters from pea size, non-exposed clusters, and shaded clusters after softening. Leaf area index and canopy porosity was estimated every 2 weeks. Midday leaf water potential was measured weekly. Light and temperature sensors were installed at the bunch level to quantify the differences in bunch temperature and light intensity among treatments. The effect of irrigation and cluster light exposure on berry weight, TSS, TA, malic acid, tartaric acid, K+, and pH were analyzed at 5 moments along grape ripening. Additionally, the phenolic profile of grapes was analyzed at harvest in 2022. During different heat waves, the natural shading technique decreased the maximum bunch temperature around 10 °C respect to the exposed bunches in both irrigation strategies. The combination of defoliation and shading techniques after softening decreased TSS at harvest and affected most of the quality parameters during the last stages of ripening, showing an interesting technique to delay ripening in warm viticulture areas.
Issue: ICGWS 2023
1CEIGRAM-Polithecnical University of Madrid, Madrid, Spain
2Bodega Ribas, Consell (Mallorca), Spain
3University of Balearic Islands-INAGEA, Palma (Mallorca), Spain