Effects of stress memory on grapevine resilience in response to recurrent drought and recovery events 

Pressing has a relevant impact on the characteristics of the must and subsequently on white wines produced [1]. Therefore, the adequate management of pressing can lead to the desired extraction of phenols and other grape compounds (i.e. Organic acids), aromas and their precursors, allowing the production of balanced wines [2]. This aspect is especially important to sparkling wine where the acidity and pH, and the content of phenols affect its longevity and the expected sensory character.

Acacia senegal gum (Asen) is an edible dried gummy exudate [1] added in young red wines to ensure their colloidal stability, precluding the precipitation of the coloring matter. Asen macromolecules, belonging to the arabinogalactan-protein (AGP) family [2], are hyperbranched, charged and amphiphilic heteropolysaccharides composed especially of sugars (92-96 %) and a small fraction of proteins (1-3 %). Asen is defined as a continuum of macromolecules that could be separated into three fractions by hydrophobic interaction chromatography (HIC) [3-4]. HIC-F1 (85-94 % of Asen), HIC-F2 (6-18 % of Asen) and HIC-F3 (1-3 % of Asen) are named and classified in that order according to their protein content, and then a growing hydrophobicity. The efficiency of Asen towards the coloring matter instability is evaluated according to an “efficacy test” that consists to determine the Asen quantity required to prevent the flocculation by calcium of a colloidal iron hexacyanoferrate solution (International Oenological Codex).

Drought and heat waves deriving from climate change have been affecting grapevine plants and altering wine characteristics in the past years, and effects are expected to get worst. Innovative approaches to address this problem have been undertaken in several varieties, that consist in exploring intravarietal variability to identify genotypes that are tolerant to abiotic stress. Such is the case of the variety Arinto, where an experimental population of 165 clones installed according to a resolvable row-column design with 6 replicates, was scanned for several parameters, including surface leaf temperature (SLT). Linear mixed models were fitted to the data of the traits evaluated, and the empirical best linear unbiased predictors (EBLUPs) of genotypic effects for each trait were obtained as well as the coefficient of genotypic variation (CVG) and broad sense heritability.

Grape phenolic content is an important quality factor that influences the appearance and mouthfeel of premium red wines.

Aims: The aims of this study were to (i) characterize bacterial and fungal communities in selected Australian vineyard soils and (ii) determine if the soil microbiome composition and diversity varied between different zones within a vineyard.