WINETECH Technical Yearbook 2021

TABLE 1. Table of aromatic precursors quantified in grapes at harvest.

YIELD PARAMETERS Minimal pruning is based on the principle that a minimally-pruned vine may become sel f-regulating in terms of balance between the vegetative growth and yield/ reproductive growth. This training system permits the elimination of pre-pruning, winter pruning and the majority of summer/green actions in the vineyard, and therefore allows a significant reduction in production costs (Rousseau, 2006). During the four seasons of this study, on average compared to VSP, MP increased yields by

France (Etchebarne et al ., 2015). Vines were trained to two systems, namely VSP and MP and received drip irrigation, intervals were scheduled with leaf water potential readings. The VSP system was spur pruned and subject to a shoot positioning action and trimming when needed, no suckering was performed. The MP treatment received no winter or summer pruning. At harvest the aromatic precursor content of the grapes were quantified, across four families of compounds (table 1).

Family of compounds

Individual compounds analysed Aromatic descriptors

hexanal, 2-hexanal, hexanol, 3-hexen-1-ol linalool, nerol, geraniol, geranic acid, p-menthane-3,8-diol benzyl alcohol, 2-phenyl-EtOH, isoamyl alcohol, isobutanol, 2-pentanol, 1-butanol, 2-heptanol, 1-octanol

C6 compounds

Herbaceous, grassy

Monoterpenes

Elderflower, rose, Muscat

Aromatic alcohols

Rose, tropical fruit, fusel

C13-norisoprenoids (only in 2013 and 2014)

3-hydroxy-b-damascenone

Floral, violet, gooseberry

FIGURE 2. Average berry size (grams per berry) of the minimal pruning (MP) and vertical shoot-

FIGURE 1. Average yield per hectare of the minimal pruning (MP) and vertical shoot-positioned (VSP) systems over four years of the trial.

positioned (VSP) systems over four years of the trial.

WINETECH TECHNICAL YEARBOOK 2021 | 51