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.

摘要：本研究旨在评估不同调控葡萄果穗结构的技术对葡萄灰霉穗腐病发病率、病情严重度，以及长相思（Sauvignon Blanc）葡萄（Vitis vinifera，欧洲葡萄）栽培性能的影响。本试验联合杀菌剂设置4组处理：对照组、盛花期喷施30 ppm赤霉素（gibberellic acid）、盛花期喷施1000 ppm调环酸钙（prohexadione calcium），以及浆果始接触期进行疏果。试验于2015、2016及2017三个采收季开展。果穗分别在盛花期、浆果始接触期、转色期（veraison）以及收获前约15天施用杀菌剂。研究结果显示，疏果不会造成长相思葡萄的产量与品质损失，尽管其对果穗结构的调控效果有限，但可有效降低灰葡萄孢（Botrytis cinerea）引发的病害发病率与病情严重度。调环酸钙可改善葡萄酚类物质成熟度，有效降低灰葡萄孢的侵染发病率与病情严重度，并通过减小果粒直径降低果穗紧密度。盛花期喷施赤霉素的处理不推荐使用，因其会降低产量与花芽育性，同时增加果粒对灰葡萄孢侵染的敏感性。