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>

<p style="text-align: justify;"><strong>Aims</strong>: The aim of this study is to test a method to extrapolate vine water status (estimated by the water potential; <strong>Ψ</strong>) over a whole appellation (protected geographical indication). The spatial extrapolation is based on an empirical approach that combines a reference site (baseline measurements) and carbon isotope discrimination (δ¹³C) values as ancillary data (AD).</p><p style="text-align: justify;"><strong>Methods and results</strong>: Experiments were conducted on the whole Tavel appellation (Gard, France). The study focused on the dominant variety: Grenache. <strong>Ψ</strong> was measured as predawn leaf water potential and was monitored over three consecutive years, 2008, 2009 and 2010, on 10, 24 and 24 sites, respectively. δ¹³C measurements were made at harvest in 2010 on the 24 sites. The spatial model (SPIDERδ) was calibrated using Ydata from 2009 and 2010 and δ¹³C data from 2010. The quality of prediction was tested on the 2008 data, considered as an independent data set. The results show that SPIDERδ was relevant in estimating <strong>Ψ</strong> at the whole appellation scale. The extrapolation model significantly improves the prediction (R² = 0.88) compared to a conventional method based on <strong>Ψ</strong> averages across the appellation (R² = 0.66).</p><p style="text-align: justify;"><strong>Conclusion</strong>: Based on a single measurement taken at time «t» on a reference site, SPIDERδ makes it possible to estimate <strong>Ψ</strong> on all sites where a δ¹³C value is available. The use of AD like δ¹³C makes it possible to consider the spatial extrapolation of <strong>Ψ</strong> with higher spatial resolution than when only direct measurements are used to calibrate the model.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: This work demonstrates the value of using an AD like δ¹³C to assess <strong>Ψ</strong> at a scale larger than the single field. This significant result opens the door to the practical use of spatial extrapolation models with higher spatial resolution.</p>