Impact of temperature and solar radiation on grape composition variability in the Saint-Emilion winegrowing area 

Grapes are one of the world’s primary fruit crops, and pruning activities generate high amounts of annual wood wastes [1]. These pruning shoots contain valuable phenolic compounds and could have numerous potential applications [1,2]. Consequently, the aim of this work was to evaluate the physico-chemical properties of vine pruning residues with potential as enological additives. For this purpose, grapevine shoots from 12 varieties grown in Chile were collected during the winter of 2021.

Bobal is the second most widely grown Spanish red grape variety (54,165 has), mainly cultivated in the Valencian Community and especially, in Utiel-Requena region (about 67% of 34,000 has). In this study, agronomic and enological parameters were determined in 98 biotypes selected during 2018 and 2019 in more than 50 vineyards over 50 years-old in the Utiel-Requena region. Moreover, a multi-criteria approach considering temperature and rainfall (Fig. 1A), among other parameters, was made to establish three different zones within the region (Fig. 1B), where in the future the selected biotypes will evaluated. In fact, in 2020, 4 replicates and 12 vines per biotype were planted in an experimental vineyard to preserve this important intra-cultivar diversity.

Vines are exposed to environmental conditions that cause abiotic stress on the plants (drought, nutrient and mineral deficits, salinity, etc.). Polyamines are growth regulators involved in various physiological processes, as in abiotic plant stress responses. Stressful conditions can modify grape’s composition, and in this work, we have focused on studying the effect of abiotic stress on the composition of polyamines and amino acids in grapes. In addition, the effect of grape variety on these compounds has been studied.

Volatile organic compounds (VOCs) are emitted by nearly all plant organs of the plants, including leaves. They play a key role in the communication with other organisms, therefore they are involved in plant defence against phytopathogens. In this study VOCs from grapevine leaves of two varieties of Vitis vinifera infected by Erysiphe necator were analysed. The varieties were selected based on their susceptibility to pathogen, Kishmish Vatkana has the Ren1 resistance gene and Zamarrica showed high susceptibility in previous trials.

One of the main aspects of Climate Change is the increase of temperatures during summer and grape maturity period. Physiological processes are influenced by these high temperatures and result in grapes with higher sugar concentration, less acidity and less anthocyanin content among other quality changes. One strategy to deal with the climate change effects is the implementation of late winter pruning to alter the effect of high temperatures during key periods by delays in maturity time.