Effect of shoot orientation on vegetative growth, yield parameters and berry composition in grapevine (Vitis vinifera L.)

A trellis system with a canopy divided in two vertical directions can present higher yields than single canopies; nevertheless, downward shoots can have lower growth, xylem hydraulic conductivity and leaf stomatal conductance than upward shoots. The main objective of this study was to evaluate the effect of shoot orientation on vegetative growth, yield parameters and berry composition in three cultivars: 'Merlot', 'Syrah' and 'Cabernet Sauvignon' in the Itata valley, Biobio Region. The trial was carried out in a commercial vineyard of 'Merlot', 'Syrah' and 'Cabernet Sauvignon'. Vegetative, yield and berry parameters were evaluated. The results confirm that downward shoot positioning reduces vegetative growth, but that leaf area is not affected. Yield is reduced in downward shoots. The concentration of anthocyanins and flavonols in the skin are not affected by downward shoot positioning. A lack of differences in must characteristics and berry phenolic composition between upwards and downwards shoots would allow for simultaneous harvest.