Techniques to modify cluster architecture and their effect on the viticultural performance of the Sauvignon Blanc cultivar

Abstract

The objective of this work was to evaluate the effect of different techniques to modify grape cluster architecture on the incidence and severity of botrytis bunch rot, as well as on the viticultural performance of the 'Sauvignon Blanc' grapevine (Vitis vinifera). Associated with fungicides, four treatments were tested: control, 30 ppm gibberellic acid sprayed at full bloom, 1,000 ppm prohexadione calcium sprayed at full bloom, and berry thinning at the stage of beginning of berry touch. The experiment was carried out in the 2015, 2016, and 2017 vintages. Clusters were treated with fungicides during the stages of full bloom, beginning of berry touch, veraison, and around 15 days before harvest. Berry thinning does not cause losses in the yield and quality of 'Sauvignon Blanc', and, despite having little effect on cluster architecture, is effective in reducing the incidence and severity of Botrytis cinerea. Prohexadione calcium improves grape phenolic maturation, is effective in reducing the incidence and severity of B. cinerea, and reduces cluster compactness by decreasing berry diameter. The application of gibberellic acid spray at full bloom is not recommended because it decreases yield and bud fertility and increases berry susceptibility to B. cinerea infection.

Modification of wine phenolic profiles by gibberellic acid application in ‘Cabernet Gernischt’ grapevines before anthesis

“…Previous studies have demonstrated that GA 3 application at full bloom is more detrimental than at pre‐bloom because it decreases grape yield and bud fertility, and increases the incidence of Botrytis cinerea infection of grape fruit 12,27 . Mundy et al .…”

“…Previous studies have demonstrated that GA 3 application at full bloom is more detrimental than at pre-bloom because it decreases grape yield and bud fertility, and increases the incidence of Botrytis cinerea infection of grape fruit. 12,27 Mundy et al found that a high rate of GA 3 application (40 mg L −1 ) reduced blooming in the following reason, 11 and Gao et al recommended applications of GA 3 above 50 mg L −1 to loosen wine grape bunching. 2 In this study, the highest concentration of pre-bloom GA 3 treatment used was 25 mg L −1 .…”

Ocorrência do míldio da videira (Plasmopora viticola L.) em função do aumento da carga de gemas da uva Cabernet Franc cultivada em região de elevada altitude de Santa Catarina

“…No entanto, observa-se nessa região condições climáticas também são favoráveis a muitos fungos que podem reduzir significativamente o rendimento e a qualidade da fruta. (DE BEM et al, 2015;BRIGHENTI et al, 2020).…”