Estudio y desarrollo del deshojado precoz como técnica para el control del rendimiento productivo de la vid (Vitis vinifera L.)Efectos sobre el desarrollo vegetativo, los componentes de la producción, así como sobre la composición y la calidad de la uva y del vino

  1. María Paz Diago Santamaría
Supervised by:
  1. Javier Tardáguila Laso Director

Defence university: Universidad de La Rioja

Year of defence: 2010

  1. Fernando Martínez de Toda Fernández Chair
  2. Belén Ayestarán Iturbe Secretary
  3. Pilar Baeza Trujillo Committee member
  4. Stefano Poni Committee member
  5. Enrique García-Escudero Domínguez Committee member
  1. Agriculture and Food

Type: Thesis


Background and aims: The economic regulation of yield is becoming more important as pressure increases to consistently produce high-quality fruit and manage production costs. The main goal of this study was to verify whether early leaf removal may be an efficient technique to regulate crop yield and to improve cluster microclimate as well as grape and wine quality in Mediterranean Vitis vinifera cultivars. Methods: Early leaf removal was manual and mechanically conducted at two timings (pre-bloom and fruit-set) in Tempranillo, Graciano and Mazuelo cultivars. The effects of early defoliation on yield components, leaf growth, canopy porosity and fruit health were assessed. Moreover, the impact on grape and wine composition as well as on the wine sensory properties was also studied. Results: Early leaf removal induced a significant decrease of fruit set, cluster weight and yield per vine. As a result, looser clusters of less number of berries were obtained. Berry weight was found to be similar or smaller than that of control but of increased relative skin and skin-to-pulp ratio. A leaf recovery response to defoliation was showed by the vines, leading to similar or even increased leaf-to-fruit ratios. Cluster exposure and canopy porosity were substantially improved, favoring a diminishment of Botrytis rot. In terms of grape composition, both technological and phenolic maturities were improved, leading to more alcoholic wines of higher anthocyanin and polyphenol (hidroxycinnamic acids and flavonols) concentrations, as well as of better mouthfeel sensory properties. Furthermore, when no biotic stress (such as Botrytis) was present, early leaf removal induced higher concentrations of resveratrol in the wines. Both timing and modality of defoliation were important in reducing yield components as well as in improving grape and wine quality and the more pronounced effects were observed for the pre-bloom and mechanical treatments, respectively. Hand removal of 4 leaves was overall ineffective in altering yield components and grape and wine composition. Conclusions: Early leaf removal may be an efficient and valid strategy for grapevine crop regulation. It is an important viticultural technique easy to be mechanically performed in order to substantially improve grape and wine quality in cultivars Tempranillo, Graciano and Mazuelo. Significance of the study: Early defoliation might become a novel, powerful and efficient technique to regulate grapevine yield and improve grape and wine quality. Its easiness of mechanization may be very interesting for the grape and wine industry, and may become an economically important alternative to traditional, expensive, and labor intensive practices, such as manual cluster thinning.