«Aztec» – the new white table grape resistant variety

Saccharomyces cerevisiae, as the workhorse of alcoholic fermentation, is a major actor of winemaking. In this context, this yeast species uses alcoholic fermentation to convert sugars from the grape must into ethanol and CO2 with an outstanding efficiency: it reaches on average 92% of the maximum theoretical yield of conversion. Moreover, S. cerevisiae is also known for its great genetic diversity and plasticity that is directly related to its living environment, natural or technological and therefore to domestication. This leads to a great phenotypic diversity of metabolites production.

In wine grape production, canopy management practices are applied to control the source-sink balance and improve the cluster microclimate to enhance berry composition. The aim of this study was to identify the optimal ranges of berry solar radiation exposure (exposure) for upregulation of flavonoid biosynthesis and thresholds for their degradation, to evaluate how canopy management practices such as leaf removal, shoot thinning, and a combination of both affect the grapevine (Vitis vinifera L. cv. Cabernet Sauvignon) yield components, berry composition, and flavonoid profile under context of climate change. First experiment assessed changes in the grape flavonoid content driven by four degrees of exposure. In the second experiment, individual grape berries subjected to different exposures were collected from two cultivars (Cabernet Sauvignon and Petit Verdot). The third experiment consisted of an experiment with three canopy management treatments (i) LR (removal of 5 to 6 basal leaves), (ii) ST (thinned to 24 shoots per vine), and (iii) LRST (a combination of LR and ST) and an untreated control (UNT). Berry composition, flavonoid content and profiles, and 3-isobutyl 2-methoxypyrazine were monitored during berry ripening. Although increasing canopy porosity through canopy management practices can be helpful for other purposes, this may not be the case of flavonoid compounds when a certain proportion of kaempferol was achieved. Our results revealed different sensitivities to degradation within the flavonoid groups, flavonols being the only monitored group that was upregulated by solar radiation. Within different canopy management practices, the main effects were due to the ST. Under environmental conditions given in this trial, ST and LRST hastened fruit maturity; however, a clear improvement of the flavonoid compounds (i.e., greater anthocyanin) was not observed at harvest. Methoxypyrazine berry content decreased with canopy management practices studied. Although some berry traits were improved (i.e. 2.5° Brix increase in berry total soluble solids) due to canopy management practices (ST), this resulted in a four-fold increase in labor operations cost, two-fold decrease in yield with a 10-fold increase in anthocyanin production cost per hectare that should be assessed together as the climate continues to get hot.

Grapevine (vitis spp.) Is one of the major and most economically important fruit crops worldwide. Unlike other cropping systems, viticulture has ancient historical connections with the development of human culture and with the socio-cultural background of grape-growing areas. The vitis genus is characterised by high levels of genetic diversity, as result of natural genetic mutations, which are common in grapevines and further assisted by ongoing vegetative propagation.

The Armenian highlands are located on the northern border of western asia and stretch up to the caucasus from the north. Throughout human history, country has played an important role in connecting the civilizations of europe and the near east. The recent large-scale study about the dual domestication origin and evolution of grapes approved that in the Armenian highlands human and grapevine stories are interlaced through centuries and roots of grapevine domestication are found deep in the pleistocene, ending 11.5 thousand years ago. Findings of this study confirmed that glacial episodes distinguish wild grapes into eastern and western ecotypes around 200-400 ka.

Polyphenols are common in human diets, primarily in plant-derived food and beverages. They influence multiple sensory properties such as aroma, flavour, colour, and taste, such as astringency and bitterness [1]. The major phenolic compounds in grapes and wines are anthocyanins and tannins (proanthocyanidins or condensed tannins).