Which heat test really represents the haze risk of a white Sauvignon wine ?

Global warming is accelerating grape ripening, leading to unbalanced wines from fruit with high sugar content but poor aroma and colour development. Reducing the size of the photosynthetic apparatus after veraison has been shown to delay technological ripeness in cool climates, but methods have not been tested in areas with high irradiance and temperature where fruit exposure could have disastrous effects on berry composition. In this Cabernet-Sauvignon trial, we compared the application of an antitranspirant (pinolene), to severe canopy topping and above bunch zone leaf removal, all performed at mid-ripening, with an untouched control. We monitored the vines weekly by measuring stem water potential, gas exchange, fruit zone light exposure. We sampled berries to measure berry weight, total soluble solids, pH, titratable acidity, and the anthocyanin profile. At harvest, we assessed yield components, measured carbon isotope discrimination, rated sunburn on clusters, and produced experimental wines. We submitted harvest samples to metabolomic profiling through PFP-Q Exactive MS/MS and wines to sensory analysis. Application of the antitranspirant significantly reduced stomatal conductance and assimilation rate but did not affect the stem water potential. Inversely, leaf removal and topping increased water potential but did not affect leaf gas exchange. The late topping was the only treatment able to decrease sugar content (up to 2Bx), increase titratable acidity and pH, and improve anthocyanin content because of lower degradation of di-hydroxylated forms. Late leaf removal above the bunch zone increased lightning conditions in the canopy and produced the most significant damage on fruits. Yield components were not affected. This work suggests that late-season canopy management can effectively control ripening speeds and improve grapes and wines. Still, the effect on grape exposure in a critical time must be well balanced to avoid problems with the appropriate technique.

The SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1) is a key floral activator that coordinates external and internal stimuli to ensure timely flowering. During early stages of flower formation, SOC1 represses floral organ identity genes such as AGAMOUS (AG) to prevent premature organ differentiation. In addition to floral organ specification, AG has been shown to regulate fleshy fruit expansion and ripening and, as such, is an important contributor to fruit quality traits. Currently, little is known about the function and gene regulatory network of the grapevine homologs VviSOC1a and VviAG1. As such, the aim of this study was to functionally characterise both genes by overexpressing them in tomato and performing phenotypic and gene expression studies.

The viticulture of the Douro Delimited Region, one of the heirs of ancestral viticulture, traditionally empirical and of quality, while integrating modernity and contemporary tools, respects and has always present the principles on which it was developed.

Each grapevine variety has a specific water use regulation response under drought, and it is still unclear whether this regulation results from innate genotypic behavior (iso- and anisohydric), or is a response to environmental factors, namely recurrent water stress priming effects. In the present work, we explored the influence of the field-grown genotypes’ drought memory in the drought-response phenotype of their vegetative progenies, in Trincadeira (isohydric) and Castelão (anisohydric) varieties under a drought event followed by recovery in a glasshouse. Cuttings from both cultivars subjected to full irrigation (FI) and non-irrigation (NI) treatments for 5 consecutive years were used.

Vintners Quality Alliance (VQA) Ontario, (Alliance de qualité Vintners) est responsable de l’administration et de l’imposition des normes en liaison avec la qualité du vin, l’appellation d’origine, les variétés de raisin et les méthodes de production. Des vins produits selon les règlements de VQA sont actuellement étiquetés de trois distinctes mais larges régions d’appellation