The Soil Component of Terroir

To obtain a quality wine, it is necessary to collect grapes in an optimal state of maturation, so the control of the ripening process is fundamental for the viticulturist.

The global non-alcoholic wine market is projected to grow from USD 2.7 billion in 2024 to USD 6.97 billion by 2034, driven by health awareness, lifestyle shifts, and religious factors [1-3]. Consequently, the removal of alcohol can significantly alter the key quality parameters of wine.

Dating back to the early domestication period of grapevine (Vitis vinifera L.), expansion of human activity led to the creation of thousands of modern day genotypes that serve multiple purposes such as table and wine consumption. They also encompass a strong phenotypic diversity. Presently, viticulture faces various challenges, which include threatening climatic change scenarios and an historical track record of genetic erosion. Paritularly with regards to wine varieties, there is a pressing need to characterize the extant genetic diversity of modern varieties, as a means to delvier knowledge-based solutions under a rapidly evolving scenario, that may enable improved yields and profiles, resistance to pathogens, and increased resilience to climate change.

Grapevine breeding is part of the research program of Agroscope in Switzerland since 1965. From 1965 to 1995, the aim of the Vitis vinifera crosses was to obtain a high resistance to grey rot (Botrytis cinerea), one of the most virulent fungal pathogens in the Swiss vineyard. In 2021, the grape varieties released from this first breeding program covered 936 ha of the 15’000 ha of the Swiss vineyard.
In 1996, a second breeding program aimed at obtaining, by classical interspecific hybridization, grape varieties resistant to downy mildew (Plasmopara viticola) and powdery mildew (Erisyphe necator) and less sensitive to grey rot (Botrytis cinerea). In order to accelerate and make the selection process more reliable, an early biochemical test was developed based on the natural defense mechanisms of the vine against downy mildew (stilbene phytoalexins). The synthesis of stilbenes (i.e., resveratrol and its oxidized dimers - and -viniférine) and pterostilbenes (methylated derivative) is among the most efficient induced defense mechanisms of grapevine against fungal pathogens on both the leaves and the clusters.

Grapevine susceptibility to fungal diseases, including the vascular disease esca, is a major threat for wine productivity and vineyard perennity worldwide.