Influence of the timing of shoot topping on yield and grape quality in 'Cabernet Sauvignon' and 'Merlot' cultivars
In grapevines, after veraison, shoot topping can balance plant source-sink ratio, directing photoassimilates to the clusters. It is also commonly practiced on vertically shoot positioned vines when shoot growth becomes too long to be supported by the trellis wires. The objective of this study was to evaluate different timing of shoot topping in 'Cabernet Sauvignon' and 'Merlot' cultivars (Vitis vinifera L.), and its effect on yield and grape quality. The experiment was conducted in high altitude areas of Santa Catarina State, Brazil, in the city of São Joaquim (28°14'57S, 49°58'49W, altitude 1,295 m). The vineyard was planted in 2005, and the plants were trained on a vertical shooting positioning trellis with spacing 3.0×1.5 m. The experimental design was completely randomised with three shoot topping dates and four repetitions, with ten plants per plot. The plants were topped in 20 cm during full bloom, 4 weeks after full bloom and 8 weeks after full bloom, during the change in berry skin colour. At harvest yield, cluster weight, number of clusters, berries number, pH, total soluble solids, acidity, polyphenols and anthocyanins were evaluated. Data were submitted to analysis of variance and Tukey's test (5% probability). According to the results it was observed that the shoot topping performed during full bloom increases the number of clusters per plant, cluster weight and yield (per plant and per hectare) for both cultivars. In 'Cabernet Sauvignon' shoot topping performed during full bloom anticipates the grape ripening, while in 'Merlot' shoot topping performed 8 weeks after full bloom increases total soluble solids and anthocyanins contents.
Vanderlinde, G., Brighenti, A.F., Malinovski, L.I., Cipriani, R., Simon, S., Sander, G.F., Allebrandt, R. and Silva, A.L. (2017). Influence of the timing of shoot topping on yield and grape quality in 'Cabernet Sauvignon' and 'Merlot' cultivars. Acta Hortic. 1157, 407-412
hedging, Vitis vinifera L., high altitude regions, phenolic maturity