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IVES 9 IVES Conference Series 9 Impact of canopy management on thiol precursors in white grapes: a six-year field study

Impact of canopy management on thiol precursors in white grapes: a six-year field study


The mechanisms behind thiol precursor accumulation in grapes remain incompletely understood, nor are the ways in which they can be improved by agronomic practices. A six-year field trial studied the physiological response of the Swiss white cultivar Vitis vinifera Arvine, rich in varietal thiols and precursors, to canopy management, i.e. leaf removal and canopy height.. Five treatments were set up in a randomized block design to assess the impacts of 1) pre-flowering LR (i.e. pre-flowering or full-flowering stages) and 2) compensating for the leaf area removed in the cluster zone by increasing the trimming height (i.e. 100 or 150 cm canopy height), compared with a non-defoliated control treatment.

Intensive pre-flowering LR severely reduced yield potential (–47% on average) and reduced the concentration of 3-mercaptohexanol precursors (P-3MH) in the must (–21%; p-value < 0.10). Decreasing earliness modulated the impact of LR on yield (–12%) and P-3MH concentration (–6%). Compensating for suppressed leaf area by increasing the trimming height slightly enhanced grape ripening (+1% total sugars; –3% titratable acidity), slightly improved the overall quality of the wine (color intensity, volume), while having no impact on must P-3MH concentration or on wine bouquet.

Observing the long-term impact of each LR treatment separately provided insights into the physiological mechanisms influencing fruit development and aroma formation. This trial is part of a larger project on canopy management and its impact on grape composition in temperate Swiss climatic conditions.


Publication date: June 13, 2024

Issue: Open GPB 2024

Type: Article


Thibaut Verdenal1*, Vivian Zufferey1, Ágnes Dienes-Nagy2, Gilles Bourdin2, Jean-Laurent Spring1

1 Agroscope, avenue Rochettaz 21, 1009 Pully, Switzerland
2 Agroscope, route de Duillier 60, case postale 1012, 1260 Nyon 1, Switzerland

Contact the author*


leaf removal, canopy height, 3-mercaptohexanol, grapevine, wine aroma


IVES Conference Series | Open GPB | Open GPB 2024


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