Berry carbon (δ¹³C) and nitrogen (δ¹⁵N) isotopic ratio reflects within farm terroir diffferences

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.

The analysis of the distribution of natural plant populations allows an ecological characterization of cultivated environments in thermal, water and trophic terms; it guides the choice or selection of plants (or grape varieties) to cultivate (Astruc et al ., 1984, 1987; Delpoux, 1971; Jacquinet and Astruc, 1979). This approach has given good results in areas where the topography is the determining factor in the ecological differentiation of the terroirs.

Wooden barrels have been the preferred method for oak maturation for wines, but the use of alternative oak products, such as staves and oak chips have increased in South Africa due to lower production costs. This study investigated the effect of different oak products used during fermentation and ageing on the sensory profile, degree of liking and perceived quality of a South African Chenin blanc wine. The different wine treatments included an unoaked tank control wine, wines matured in 5th fill barrels, wines matured in new barrels from three different cooperages, and wines matured in 5th fill barrels with stave inserts from two different cooperages.

The management of oxygen during winemaking and aging is a big issue in order to achieve high quality wines. The correct amount of O2 improves aroma, astringency, bitterness and color, however an excess of oxygen promotes the appearance of yellow

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.