The chemical composition of disease resistant hybrid grape cultivars and its impact on wine quality: an exploratory enquiry into sustainable wines

One of the reasons of the spread of grapevine virus diseases in
vineyards around the world is the lack of knowledge by the main actors of the wine sector. To face this problem, five partners worked together to develop the PAThOGEN project, a training program aimed to improve grapevine virus knowledge and management. The partnership gathers one French technical center (IFV), one Spanish university (USC), one Italian applied research center (CREA), one Spanish foundation
specialized in training and technology transfer (FEUGA) and one Italian SME specialized in the development of informatics tools and in knowledge transfer (HORTA).The objectives of PAThOGEN are: (i) to develop and
maintain a high-quality work-based Vocational and Education Training program, (ii) to improve the skills of professionals of the wine sector.

The increasing frequency of wildfires in grape-growing regions is seen as a significant risk for the grape and wine industry.

In the last decades, climate change required already adaptation of vineyard management. Increase in temperature and unexpected weather events cause changes in all phenological stages requiring new management tools. For example, defoliation can be a useful tool to reduce the sugar content in the berries creating differences in the wine profiles. In a ten-year field experiment using Riesling (Vitis vinifera L, planted 1986, Geisenheim, Germany), various mechanical defoliation strategies and different intensities were trialed until 2016 before the vineyard was uprooted. Wood was sampled from the plant compartments root, trunk, cordon and shoot for analyses of physicochemical properties (e.g. lignin and element content, pH, diameter), nonstructural carbohydrates and the microbial communities. The aim of the study was to investigate the influence of reduced canopy leaf area on the sink-source allocation into different compartments and potential changes of the fungal and prokaryotic wood-inhabiting community using a metabarcoding approach. Severe summer pruning (SSP) of the canopy and mechanical defoliation (MDC) above the bunch zone decreased the leaf area by 50% compared to control (C). SSP reduced the photosynthetic capacity, which resulted in an altered source-sink allocation and carbohydrate storage. With lower leaf area, less carbohydrates are allocated. This for example resulted in a decreased trunk diameter. Further, it affected the composition of the grapevine wood microbiota. SSP and MDC management changed significantly the prokaryotic community composition in wood of the root samples, but had no effect in other compartments. In general, this study found strong compartment and less management effects of the microbial community composition and associated physicochemical properties. The highest microbial diversities were identified in the wood of the trunk, and several species were recorded the first time in grapevine.

In previous experiments carried out in Bologna on Sangiovese grapevines raised with the Australian “Minimal Pruning” system, it has been shown that this system left an excessive burden of buds on the vine.

Port wine is a fortified wine exclusively produced in the Douro Appellation (Portugal) under very specific conditions resulting from natural and human factors. Its intrinsic aroma characteristics are modulated upon a network of factors, such as the terroir, varieties and winemaking procedures that include a wide set of steps, namely the fortification with grape spirit (ca. 77% v/v ethanol).