Nitrogen uptake, translocation and YAN in berries upon water deficit in grapevines with contrasting stomatal sensitivity

Nowadays, winemaking is dealing with great challenges, notably climate change, disease resistance and low pesticide inputs, desire for more sustainable agricultural productions and permanent changing of consumer preference. Trying to propose practice improvements, scientists are exploring vine hybridization a paradoxically old but still actual way to take up such challenges

La région viticole de Mendoza est la principale zone vitivinicole d’Argentine qui se compose de 3 oasis (Nord, Valle de Uco, Sud). La première zone vitivinicole, située dans l’oasis Nord, est composée par les département de Luján de Cuyo et Maipu. C’est la zone de production la plus ancienne et la plus reconnue pour la qualité de sa production. Ce travail se porte plus particulièrement sur le département de Luján de Cuyo qui constitue le lieu traditionnel de production du Malbec argertin. Ce travail propose de caractériser les terroirs et de mettre en avant leurs typicités.

Enzymatic browning (BE) of must is caused by polyphenol oxidases (PPOs), tyrosinase and laccase. Both PPOs can oxidize diphenols such as hydroxycinnamic acids (HA) to quinones, which can later polymerize to form melanins [1], which are responsible of BE in white wines and of oxidasic haze in red wines. SO₂ is the main tool used to protect must from BE thanks to its capacity to inhibit PPOs [2]. However, the current trend in winemaking is to reduce and even eliminate this unfriendly additive. Among the different possible alternatives for protecting must against BE, the inoculation with a selected Metschnikowia pulcherrima MP1 is without any doubt one of the most promising ones.

In recent years, developing more efficient and sustainable viticulture management has been essential due to the impact of climate change in semiarid regions. For this reason, the use of recycled organic mulching (ROM) in the vineyard has become an interesting strategy to cope with water stress, isolated soil from extreme temperatures and improving soil humidity, control the presence of weeds and therefore reduce the inputs of herbicides and improve soil fertility. This work aimed to analyse the effect of three different organic mulches [straw (S), grape pruning debris (GPD) and spent mushroom compost (SMC)] and two traditional soil management techniques [herbicide (H) and interrow (IN)] on weed coverage and the spontaneous plant communities’ presence. Data sampling was collected throughout the vine vegetative cycle of 2021 in La Rioja, Spain. The different soil management techniques had a clear effect on weed coverage and his development during the vine vegetative cycle. SMC and H were the treatments with the highest and the lowest coverage percentage, respectively. IN had a delayed weed emergence at the beginning of the vine vegetative cycle, but finally it reached maximum values nearby SMC. GPD and S had similar effects on weed emergence, reaching 25-30% of the maximum coverage values. A total of 29 herbaceous species were identified during the vegetative cycle, some of them very isolated and occasional. Principal component analysis (PCAs) showed a good association between spontaneous species and treatments, furthermore, specific species-treatment associations were found. Moreover, three clear groups of herbaceous communities were identified by cluster analysis. This study provides interesting information about the effect of different alternative soil management on herbaceous plant coverage and weed species communities which could contribute to making more sustainable viticulture.

The concept of Appellation d’Origine Contrôlée (AOC) is based on the existence of a link between the characteristics of the terroir and the quality and typicality of the production (DELAS, 2000). If for a long time, this link only appeared as the fruit of empiricism, the research undertaken recently has made it possible to scientifically establish the complex relationships between the functioning of natural environments and the ability to produce quality.