Application of remote sensing by unmanned aerial vehicles to map variability in Ontario Riesling and Cabernet Franc vineyards

Having the possibility to use a wide spectrum of elecromagnetic waves, dielectric spectroscopy is a technique commonly used for electrical characterization of dielectrics or that of materials with high energy storage capacity, just to name a few. Based on the electrical excitation of dipoles (polymer chains or molecules) or ions in relation to the characteristics of a weak external electric field, this method allows the measurement of the complex permittivity or impedance of polarizable materials, each component having a characteristic dipole moment.In recent years, the food industry has also benefited from the potential offered by this technique, whether for the evaluation of fruit quality or during the pasteurization of apple juice [1-3]. As the tests are fast and do not destroy the products, dielectric spectroscopy proved to be an experimental tool suitable for online measurements as well as long-term monitoring.

Vineyard canopy features such canopy porosity and fruit exposure influenced microclimate, fungal disease incidence and grape composition. An objective, rapid and non-invasive method to assess and map the canopy status is needed to apply in precision viticulture. A new method for canopy status assessment and mapping based on non-invasive machine vision was applied in commercial vineyards in this work.

Downy and powdery mildew are major issues in grapevine cultivation, requiring many phytosanitary treatments to ensure yield and quality. Climatic changes are also challenging grape cultivation

The marked climate change impact on vine and grape development (phenology, sugar content, acidity …) is one of the manifestations of Genotype X Environment X Management interactions importance in viticulture. Some practices, such as irrigation, can mitigate the effect of water deficit on grape development, but warming is much more difficult to challenge. High temperatures tend to alter the acid balance of the fruit with a parallel increase in sugar concentration. In the long term, genetic improvement to select varieties better coping with temperature elevation appear as a good option to support sustainable viticulture. Nevertheless, the existing phenotypic diversity for grape quality components that are influenced by temperature is poorly understood, which jeopardizes breeding strategies.

Context and purpose of the study. `Grüner Veltliner´ is the most important Austrian white quality wine variety, which is mainly used to produce primary fruity wines.