Effect of Methyl Jasmonate Plus Urea Foliar Application on the Polysaccharide and Monosaccharide Composition of Tempranillo Grapes and Wines and on the Wine’s Quality

Polysaccharides are the main group of macromolecules in wines. Climate change is a major problem for viticulturists as it leads to the production of unbalanced grapes. This is attributed to a mismatch between the technological maturity and phenolic maturity of grapes, which can negatively impact the production of high quality wines. To mitigate this effect, biostimulants can be applied to grapevines. For the first time in the literature, this work studied the foliar application of methyl jasmonate plus urea (MeJ + Ur) on the vineyard and its effect on the monosaccharide and polysaccharide composition of Tempranillo grapes and wines over two consecutive seasons. To achieve this, the extraction and precipitation of polysaccharides was conducted, and the identification and quantitation of monosaccharides was performed via GC–MS. The effect of MeJ + Ur foliar treatment in both the grapes and wines was season-dependent. The MeJ + Ur treatment had a slight impact on the monosaccharide composition of the grapes and also demonstrated a small effect on the wines. Multifactor and discriminant analysis revealed that the season had a greater influence on the monosaccharide and polysaccharide composition of grapes and wines compared to the influence of MeJ + Ur treatment. Interestingly, the MeJ + Ur-treated wines exhibited a higher sensory evaluation than the control wines in the second vintage. To gain further insights into the effect of MeJ + Ur foliar application on the monosaccharide and polysaccharide composition of grapes and wines, further investigations should be conducted

Foliar Applications of Calcium, Silicon and Their Combination: A Tool to Improve Grape Composition and Quality

Foliar nutrient sprays are broadly used in commercial agriculture. To date, the application of Ca and Si has been little explored in vineyard production but may lead to positive responses at various levels. Therefore, the aim of this work was to evaluate the effect of supplying single or combined calcium (Ca, 120 mM) and silicon (Si, 120 mM) sprays in Tempranillo grape composition. Foliar treatment with Ca + Si foliar enhanced all families of aromatic compounds, whereas single Ca and Si sprays induced lower effects. Regarding phenolic compounds, all foliar treatments led to minor effects. However, all three foliar Ca and Si treatments increased the total grape amino acid content. Consequently, the application of combined Ca and Si sprays to a vineyard is recommended as a tool for improving grape quality