Juvenile-to-adult vegetative phase transition in grapevine 

Mannoproteins are polysaccharides released by Saccharomyces cerevisiae yeast during alcoholic fermentation or by enzymatic action during aging on yeast lees (autolysis). These molecules play a major role in wine characteristics processing, namely, in the tartaric stabilization and protein haze prevention; moreover, they improve color stability and reduce astringency.

Cover crops are increasingly considered in Mediterranean climate vineyards due to a combination of agronomic and regulatory considerations. However, the soil under the vines themselves is typically kept free of vegetation by mechanical plowing or herbicide spraying. Taking into account that these practices may convey a number of non-favourable economic and environmental implications, and the fact that drip irrigation can ease the use of cover crops under the vines, the aim of this work was to evaluate the agronomic implications and the changes in soil physical and biological properties caused by an under-vine cover crop in a Mediterranean area.

Copper (Cu) is widely and historically used in viticulture as a fungicide against mildew. Cu has a strong affinity for soil organic matter and accumulates in topsoil horizons. Thus, Cu may negatively affect soil organisms and plants, consequently reducing soil fertility and productivity. The Bordeaux vineyards have the largest vineyard surfaces (26%) within French controlled appellation and a great proportion of French wine production (around 5 million hl per year). Considering the local context of vineyard surfaces decreasing (vine uprooting) and possible new crop plantation, the issue of Cu potential toxicity rises. Therefore, the aims of this work are firstly to evaluate the Cu contamination in vineyard soils of Bordeaux, secondly to produce a risk assessment map for new vine or crop plantation. We used soil analyses from several local studies to build a database with 4496 soil horizon samples. The database was enhanced by means of pedotransfer functions in order to estimate the bioaccessible (EDTA-extractable) Cu in soils of samples without measurements. From this database, 1797 georeferenced samples with CuEDTA concentrations in the topsoil (0-50 cm depth) were used for kriging interpolation in order to produce the spatial distribution map of CuEDTA in vineyard soils. Then, the spatial distribution of Cu was crossed with vine uprooting surfaces and municipality boundaries. CuEDTAconcentrations ranged from 0.52 to 459 mg/kg and showed clear anomalies. Our results from spatial analysis showed that almost 50% of vineyard soil surfaces have CuEDTA concentrations higher than 30 mg/kg (moderate risk for new plantation) and 20% with concentrations higher than 50 mg/kg (high risk for new plantation). A decision-support map based on municipalities was realised to provide a simple tool to stakeholders concerned by land use management.

Wines exhibit profound chemical complexity which arise from a diverse array of compounds that contribute to its sensory profile.

The aim of this work is to determine the influence of viticultural and oenological factors to the aromatic potential of white wines from Colombard variety in the south west of France Gascony vineyard.