Looking for a more efficient genotypes in water use. A key for a sustainable viticulture

Consumers’ demand for non-alcoholic wine has notably increased in the last years: this trend is a consequence of a growing interest in more healthy habits, and as a response to higher alcohol levels in wine due to climate change. In addition, drinking limitations due to physiological/pathological conditions (e.g., pregnancy, diabetes, hepatic disorders), driving regulations, ethical/religious considerations, and high import taxes on alcoholic beverages have positively influenced this marked (us$ 1.6 billion in 2021). International organisation of vine and wine (OIV) established that alcohol content defining wines must not be less than 8.5% vol, (OIV, 2017).

Aim: Terroir is a French concept relating the qualities and quality of agricultural products to their physical and socio-cultural place of origin. It is increasingly used by business and policymakers as a marketing technique to provide economic benefits (e.g. Lenglet, 2014; Wine Australia, 2015), and to potentially preserve cultural heritage (e.g. Bauer, 2009) and the environment (e.g. Bowen, 2010)

Our research aimed to determine the effect and efficiency of foliar application of urea on the phenolic composition of Tempranillo Blanco grapes. The field experiment was carried out in 2019 and 2020 seasons and the plot was located in D.O.Ca Rioja (North of Spain). The vineyard was Vitis vinifera L. Tempranillo Blanco and grafted on Richter-110 rootstock. The treatments were control (C), whose plants were sprayed with water and three doses of urea: plants were sprayed with urea 3 kg N/ha (U3), 6 kg N/ha (U6) and 9 kg N/ha (U9). The applications were performed in two phenological stages, pre-veraison (Pre) and veraison (Ver). Also, each of the treatments was repeated one week later. Control and treatments were performed in triplicate and arranged in a randomised block design. Grapes were harvested at optimum ripening stage. High-performance liquid chromatography was used to analyse the phenolic composition of the grapes. Finally, the results obtained from the analytical determinations – flavonols, flavanols and non-flavonoid (hydroxybenzoic acids, hydroxycinnamic acids and stilbenes) – were studied statistically by analysis of variance. The results showed that, in 2019, U6-Pre and U9-Pre treatments increased the hydroxybenzoic acid content in grapes, and also all foliar treatments applied at Pre enhanced the stilbene concentration. Moreover, U3-Ver was the only treatment that rose flavonol and stilbene contents in the Tempranillo Blanco grapes. In 2020, all treatments applied at Pre enhanced the flavonol concentration in grapes. Furthermore, U3-Pre and U9-Pre treatments increased stilbene content in grapes. Nevertheless, the hydroxybenzoic acid content was improved by U6-Ver and U9-Ver and besides, hydroxycinnamic acid concentration in grapes was increased by all treatments applied at Ver. In conclusion, the lower and highest dose of urea (U3 and U9), applied at pre-veraison, were the best treatments to improve the Tempranillo Blanco grape phenolic composition.

AIM: The application of microwaves (MW) to the grape is a technique to reduce the contact time with pomace because it allows to break the cell walls of the berry.

Context and purpose of the study. Modern viticulture is facing significant challenges due to global climate changes, spanning from extreme heat spells and water scarcity to the acceleration of grapevine’s phenological development with important consequences from budbreak to harvest.