Reduced berry skin epi-cuticular wax and cutin accumulation associates with a genomic deletion and increased polyphenols extractability in a clone of Tempranillo Tinto 

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.

Climate change projections point to an increase of temperatures and changes in rainfall patterns in the mediterranean region.

Iron (Fe) deficiency is one of the important nutritional disorders for grapevine growing in alkaline and calcareous soils. Although Fe is an abundant element in soil, several factors limiting its availability, particularly the high levels of calcium carbonate or bicarbonate in soil, leading to a remarkable reduction in grapevine growth and productivity. The use of Fe chlorosis-tolerant rootstocks seems to be a cost-effective and efficient way to maintain Fe balance. Morphological and physiological changes occur in plants to cope with low Fe availability, including enhancement of ferric chelate reductase activity and altering root system by increasing lateral roots and root hairs.

Winter pruning is today the longest operation for hand workers in the vineyard. Over the last years, mechanical pruning practices have become popular in southern France vineyards to respond to competitiveness issue especially for the basic and mid-range wine production. Wine farmers have developed different vineyard management techniques associated with mechanical winter pruning. They sought to be precise or not to control the buds number per vine.

Cork taint decreases the commercial value of wine as tainted wines are rejected by consumers. Although other compounds in wine and cork can also be responsible for causing a taint, 2,4,6-trichloroanisole (TCA) is regarded as the primary cause of cork taint. As cork taint is often used in marketing campaigns against natural cork closures,