New fungus-resistant grapevine varieties display high and drought-independent thiol precursor levels

Elevated temperature during the grape maturation period is a major threat for grape quality and thus wine quality. Therefore, characterizing the grape composition response to temperature at a larger scale would represent a crucial step towards adaptation to climate change. In response to changes in temperature, various physiological mechanisms regulate grape composition. Primary and secondary metabolisms are both involved in this response, with well-known effects, for example on anthocyanins, and lesser known effects, for example on aromas or aroma precursors. At the field scale or at the regional scale, however, numerous environmental or plant-specific factors intervene to make the effects of temperature difficult to distinguish from overall variability. In this study, it was attempted to overcome this difficulty by selecting well-characterized situations with differing temperatures.
A long-term study of air temperature variability across several Merlot vineyards in the Saint-Emilion and Pomerol wine producing area found significant temperature differences and gradients at various time scales linked to environmental factors. From this study area, a few sites were selected with similar age, soil and training system conditions, and with repeated and contrasted temperature differences during the maturation period. The average temperature difference during the maturation period was about 2°C between cooler and warmer sites, a difference similar to that expected under future climate change scenarios. In close vicinity to the temperature sensors at each site, grape berries were sampled at different times until full maturity during 2019 and 2020. Also, berries from bunches on either side of the row were analyzed separately, allowing an investigation of bunch exposure effect associated with the coupling of berry temperature and solar radiation. Four replicates of pooled berries for each time – site – bunch exposure combination were obtained and analyzed for biochemical composition. Analyses of variance of the biochemical composition data collected at different sampling times reveal significant effects associated with temperature, site, and bunch azimuth. For instance, anthocyanins in grape skins are clearly influenced by temperature and solar radiation exposure, with up to 30% reduction in warmer conditions.

An integrated terroir characterization is currently realized in the French northern vineyard: “Anjou”. The concept of Basic Terroir Unit (B.T.U.) and its associated ground model “Rock, Alteration, Alterite” are used in this characterization. This work is coupled to a viticultural survey, based on parcels.

It is important to examine the yield quality elements of table grape varieties. There are great differences in winter and summer pruning of the early sweet grape variety. For this reason, in the study, the effects of different crop loads and pruning processes on grape yield, quality characteristics and vine development in the early sweet (vitis vinifera L.) Grape variety were investigated.

Kokumi is a complex sensation perceived as enhanced palatability. Under the influence of kokumi substances, foods/beverages tastes become more flavorful with increased intensity, spread, continuity, richness, harmony, and punch which are the six related characteristics corresponding to the Kokumi sensory concept [1].

We performed a DC resistivity monitoring experiment during eight months in 2003. Low, medium and high resolution measurements have been carried out at various locations of a vineyard. General apparent resistivity mapping evidences the spatial variations of the summer drying of the subsurface.