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<p style="text-align: justify;"><strong>Aims</strong>: An analysis of the asynchrony and dynamics of dry matter accumulation and water content in the grape berries growth period (Vitis vinifera L.) was carried out on a macroscopic scale (berry population). Experimental studies suggest a framework to evaluate the asynchronous nature of grapevine maturation and to propose a simple model to simulate dry matter and water dynamics.</p><p style="text-align: justify;"><strong>Methods and results</strong>:Amethodology based on the measurement of the density of the berries was used, providing information on the dry matter, water content and distribution of the berry populations during the veraison - harvest period. The main experiment was carried out in Rhone valley vineyards on the«Grenache N » and « Syrah » varieties. Additional information was gathered in Burgundy vineyards on « Pinot noir » and « Chardonnay » varieties. A relationship between the sugar content (°Brix) and water content of a berry was observed, which was robust and identical for all varieties. The asynchronous nature of berry growth was confirmed and densimetry allows quantifying the homogeneity of harvest. A model was proposed to modelling dry matter growth, based on thermal time and final potential dry weight. A single relationship was obtained for the two varieties studied which seemed to be independent of field conditions (soil and year). To model water content dynamics (or °Brix, using the relationship obtained between them), two components were defined, one of which is related to the berry phenological stage and the other depends on the water status of the plant.</p><p style="text-align: justify;"><strong>Conclusion</strong>: The results provide a conceptual framework to better understand and represent the dynamics of dry matter accumulation and water content of a population of grape berries, and to evaluate the asynchronous nature of grapevine maturity.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: The models and relationships proposed could be used as a tool to better identify and understand key factors and processes occurring in the field until the detailed processes of berry growth are better understood and can be incorporated into the model. This model could be incorporated into a crop model of vine growth.</p>

We studied the effect of vine water status on the dimethyl sulfur potential (DMSP), ammonium, and amino acid contents of the berry during the maturation of Grenache Noir grapes. Water deficit increased the accumulation of amino acids in berries and favored yeast assimilable amino nitrogen. Similarly, ammonium content was higher in berries from vines subjected to moderate water deficit. DMSP content followed the same trend as yeast assimilable amino acid content, with higher concentrations observed in the berries of vines subjected to water deficit. The high DMSP and yeast assimilable nitrogen contents of musts from vines subjected to water deficit resulted in a better preservation of DMSP during winemaking. The wines produced from these musts had a higher DMSP level and would therefore probably have a higher aroma shelf life, because the DMSP determines the rate of release of dimethyl sulfur during wine storage, and this compound enhances fruity notes.

<p style="text-align: justify;"><strong>Aim</strong> : The objective of this work was to test an approach to extrapolate the vine water status (<strong>Ψ</strong>) over a whole denomination. The method has already been tested at the field level, but it has never been validated on a spatial scale that large.</p><p style="text-align: justify;"><strong>Methods and results</strong> : The extrapolation model is based on an empirical approach that relies on a reference measurement and a spatial model of <strong>Ψ</strong>. Experiments were carried out over the 2946 ha of the denomination of Tavel (Gard, France). This site exhibits significant spatial variability in soil composition (three different soil units) and elevation, it is not irrigated and has a Mediterranean climate. This context leads to strong spatial variability in <strong>Ψ</strong>. Focusing on the most common grape variety used in the denomination, Grenache, a data base of predawn leaf water potential (PLWP) was built over three consecutive years (2008, 2009 and 2010). Respectively 10, 24 and 24 sites located throughout the denomination have been monitored for PLWP. The monitoring consisted respectively in 7, 10 and 9 measurement dates throughout the growing season. The spatial model was calibrated from 2009 and 2010 data and the prediction was tested on 2008 data. The results showed that the approach was completely transferable to a large territory like Tavel. The model significantly improved the quality of the prediction (R² = 0.9) compared to a conventional non-spatial method based on the mean values (R² = 0.61).</p><p style="text-align: justify;"><strong>Conclusion</strong>: On the basis of a single measurement taken at time “t” on a reference site, the model makes it possible to estimate <strong>Ψ</strong> on any site of the study area. The results, therefore, demonstrated the ability to extrapolate a PLWP measurement made on a reference site over the whole denomination constituted of three different soil units.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: This study represents a significant step since it demonstrates the existence of a spatial model of <strong>Ψ</strong> at a scale larger than the single field. It provides critical knowledge to consider the use of an empirical spatial model across a relatively large territory. This step opens up the possibility to provide spatial extrapolation model of <strong>Ψ</strong> based on data assimilation or existing data base.</p>

Aims :Awaterstressindexbasedonawaterbalancemodel was tested as a tool for classifying the water stress paths experiencedbygrapevinesinvariousFrenchMediterranean vineyards. The relations between the index value and grapevine yield and berry quality (sugars, organic acids, anthocyanins)atharvestwereinvestigated. Methods and results : A data set of 102 situations, each combining one location, one variety, one vintage and one water regime (irrigation or, most often, no irrigation), was collected for the study. The Fraction of Transpirable Soil Water (FTSW) was simulated by a unique-soil-reservoir water balance model at a daily time step. Five classes of water deficit were delimited from specific decreasing thresholds of FTSW over four periods between flowering and harvest. These thresholds were derived from predawn leaf water potential values because over decades, grapegrowers and researchers have shared references and built expertise by using this variable throughout the Mediterranean region. A water stress index resulting from thelevelsofwaterdeficitreachedateachofthefourperiods ofthecyclewascalculated.Thisindexwascorrelatedwith yield per vine, berry weight, and berry sugar and organic acidcontentsbutnotwithberryanthocyanincontent. Conclusion : A simple water stress index, based on the waterbalancemodel,exhibitedsignificantcorrelationswith yield and berry quality for various cultivars and pedo-climaticconditionsinMediterraneanvineyards. Significance and impact of the study : This water stress indexisavaluabletoolforexplainingthevariationsingrape yieldandqualityofgrapeamongvariouslocationsandyears because it reflects the vineyard water stress history, in relationtorainfallregimeandsoilconditions.Improvement would come from the simulation of FTSW during winter, notablyforsoilsofhighTotalTranspirableSoilWater.One potential application is the quantification of water stress change brought by irrigation in Mediterranean vineyards, anditsrelationtograpevineproduction. Abstract Résumémanuscript received 18th