Proceedings of the 20th GiESCO International Meeting (2017)

In recent years, sunburn has become a major concern to viticulture throughout the world. Given that grapevines differ in heat tolerance, the incidence of sunburn is likely to vary among different cultivars.

Climate change is affecting viticulture particularly because in wine production most of the value is provided by the desired tipicity. High air temperatures decouple grape sugars and anthocyanins accumulation impacting negatively wine composition. In this trial, carried out under the temperature-warm and semi-arid conditions of eastern Spain, we assessed two field strategies in cv. Bobal and Tempranillo aiming to delay ripening to cooler periods; 1) late leaf removal (LLR) and 2) late pruning (LP).

Rotundone is the aroma compound responsible for peppery aroma in red wines which was discovered in 2008 in a Syrah wine from Australia. More recently, it has been found in several cultivars grown in the South West of France such as Duras, Gamay and Malbec.

According to IPCC, in 2001-2010 floods have been the most frequent extreme event. Root exposure to prolonged hypoxic conditions produced by temporary flooding of the soil, may induce the synthesis of stress hormones, the production of reactive oxygen species and undergo metabolic re-programming.

Grapevines are useful model plants for research on the physiology of water stress responses. Variable responses at the stomatal level have been described in different varieties with implications on the hydraulic conductance of the plant and eventually impacts on the tension imposed to the xylem architecture, depending on xylem properties. In order to assess possible associations between stomatal responses (gs) to evaporative demand (VPD), water potentials at the root to leaf gradient, plant hydraulics and xylem morphoanatomical traits, a two-season research study has been conducted in Cabernet Sauvignon (CS), Carmenere (C) and Syrah (S) in the field, under mild water stress (MWS) and well watered (WW) conditions.

Green pruning provides better conditions to the vegetative canopy of the vine, favoring aeration and insolation in the region of the bunches, providing better conditions for its maturation. The use of plant regulators, such as abscisic acid (ABA), has also been studied to increase the concentrations of phenolic compounds in the berry peel of the treated grapes, improving their coloration.

Physiological measurements are the most accurate way of assessing plant water status. However, they are time-consuming, costly and invasive for the plant. Visible to shortwave infrared imaging spectrometers can be used to detect and monitor several biochemical variations in the leaf offering a faster, cheaper and non-destructive alternative to the traditional methods. In this study, hyperspectral images were used to obtain the spectral signatures of grapevine leaves (Vitis Vinifera L. cv. Shiraz) under different water conditions.

For the west of Argentina, vitiviniculture represents the main agricultural industry. In the irrigated valleys where viticulture is developed, the problems of salinity and toxicity of some ions in the soil limit productivity and quality of the obtained products. The tolerance to toxic ions (Cl-, Na+, B (OH)4-) of the commercial grape cultivars is rather low, but it is feasible to use rootstocks that withstand high levels of ions in the soil through different mechanisms.

Several previous open-field experiments have shown that foliar applications with guaiacol solutions can modify wine volatile composition. After such treatment, guaiacol glycoconjugates were detected in fruits, leaves and shoots of Monastrell variety, suggesting that aglycone compounds could be released during wine processing with some changes on the wine aroma.

In this study, the response of Tannat, an emblematic variety of the Uruguay, to the modification of the source relationship (S/S) was evaluated, through the leaf removal on fruit set and thinning of clusters at veraison, measuring the composition of the grape.