Late winter pruning is proposed as an economical technique to postpone budding and, in some cases, grape ripening.

However, the greater the delay in canopy regrowth in spring, the lower the production : fine-tuning is needed before large-scale dissemination.

For 2 years, standard, late and very late winter pruning were compared for a Guyot-grown Chardonnay. These 2 theses were applied when the apical shoots of the vertical shoots that had not yet been pruned had about 1-3 and 3-5 unfolded leaves, respectively. The leaf area per vine removed was 0.40 and 0.89 m2 (2020) and 0.04 and 0.08 m2 (2021), respectively. The two theses postponed harvest by 20 and 23 days in 2020, while a milder effect, 8 days, was recorded in 2021. The late pruning theses reduced yield per stump by 69 and 79% (20) and 11 and 20% (21), respectively; independent of seasonal variability and pruning time, yield limitation increased from distal to basal shoots depending on reduced fertility.

The data showed negative correlations between leaf area removed in spring versus yield and sugar concentration at harvest, and allow more accurate identification of the combination of pruning time x leaf area removed that could reconcile delayed phenology and decreased yield limitation in Guyot-trained Chardonnay vines.

Initiative carried out under the VIRECLI Operational Group, co-financed by FEASR Operation 16.1.01 “PEI Operational Groups” of the Rural Development Program 2014 – 2020 of the Lombardy Region (Italy).
Lead partner of the partnership: University of Milan
Managing Authority of the Program: Lombardy Region

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