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The aim of this study was to assess the relationships between the soil water-holding capacity (SWHC), nitrate nitrogen (N-NO ) and extractable potassium (K) content of soil; the vine nutrient content, vigour and yield; and the quality of the musts and wines in DOCa Rioja vineyards over a five-year period (2010–2014). The SWHC, N-NO and extractable K content of the soil were analysed in twelve cv. Tempranillo (Vitis vinifera L.) plots. Vine yield, nutritional parameters and the K and polyphenol compounds in the musts and wines were determined. In general, both the SWHC and the soil N-NO content were positively correlated with the N and K content of the petiole, the shoot weight and the bunch weight, but negatively correlated with the polyphenol and anthocyanin content of the musts and wines. The K extractable content was also correlated with the K content of the petiole and with the K in the musts and wines. The SWHC, the N-NO and the extractable K are soil parameters which have been linked to the growth and ripening of the vine plant and to the composition of the must and wine. For DOCa Rioja agroclimatic conditions, assessment of these soil parameters would enable selecting soils that support obtaining wines of better quality.

Polysaccharides in wine play important roles in the stabilization and in the sensory properties of wines. Elicitor application constitutes an interesting field of research since it is indirectly involved in the accumulation in grape cell walls of molecules like callose, lignin, phenolic compounds and glycoproteins. Currently, biomimetic calcium phosphate (ACP) nanoparticles are successfully used in viticulture for the controlled delivery of bioactive molecules, such as elicitors. The aim of this study was to compare the effect of the application of two different elicitors on both grape and wine of Tempranillo polysaccharide composition. Methyl jasmonate (MeJ) and nanoparticles doped with MeJ were applied to the canopy at veraison and one week later in two vintages. In the grape extracts, the foliar treatments did not increase the content of monosaccharides or that of the main pectin families; therefore, the elicitors did not reinforce the cell walls of the Tempranillo grape. The extractability and solubility of the pectic families of the grape cell walls into the wine depended on the type of family and the climate of the vintages.

Two of the main challenges of Mediterranean viticulture is low water quality and the risk of increasing concentrations of mineral salts in the root zone. This work was undertaken to study the impact of saline deficit irrigation on grape and wine phenolic composition, as well as on the sensory profile of the wines. The experiment was carried out during three consecutive years (2016-2018) in a commercial vineyard of cv. Monastrell (Vitis vinifera L.) grafted onto 1103P rootstock located in D.O. Jumilla (SE Spain). Three watering regimes were carried out: i) the control (“Control”): the vines were irrigated with water of standard quality, ii) Sulfate treatment (“Sul”): the vines were irrigated with saline water (Na₂SO₄ + MgSO4), and iii) Chloride treatment (“Chl”): the vines were irrigated with saline water (NaCl). The same amount of irrigation water was applied to all the treatments. The water electrical conductivity was 1.8 dS/m for Control and 5 dS/m for the saline treatments (Sul and Chl). Both the Sul and Chl treatments reduced the berry weight in all the study years compared to Control, although this difference was statistically significant in the last year only (p ≤ 0.05). No significant differences (p > 0.05) were observed in the grape quality parameters. However, the saline treatments slightly increased grape total soluble solids (TSS) in two out of the three study years compared to Control. Regarding the phenolic composition, no significant differences (p > 0.05) among treatments were found in grapes and wines. In general, the wines from vines irrigated with saline waters received the best scores by the panel in the sensory profile analysis. The use of saline waters could be employed in the case of water scarcity, as long as the vineyard is planted on a rootstock tolerant to salinity, such as 1103P, and the vineyard soil has a texture that favours leaching.

Currently, elicitors have been used to induce the defence mechanisms of vines, i.e., against both abiotic and biotic stresses. Besides, increases in phenolic synthesis in grapevines have been reported after elicitors application. However, its effects on the grape nitrogen composition are not entirely known. Thus, this work aimed to study the effect of methyl jasmonate (MeJ) and a yeast extract (YE) applied in Monastrell and Tempranillo grapevines on grape amino acids during two consecutive seasons. Amino acids in grapes were analysed by HPLC. In the first season, the total amino acid content in grapes decreased in Monastrell after MeJ and YE applications from 2236 to 1580 and 1620 mg L, respectively, while in Tempranillo, the total amino acid concentration decreased after YE applications from 2355 to 1811 mg L. However, during the second season, elicitors did not affect total amino acid concentration. The most important components of variability in amino acid concentration were the grape variety and the season. These results provide new knowledge of the effect of two elicitors in two important red varieties on grape amino acids content, relevant for wine quality.

Aim: An oxidation process frequently occurs during white winemaking, affecting its quality. The aim was to study, for two years (2013 and 2014), the effects that foliar applications of vine-shoot (Airén (AVS) and Moscatel (MVS)) and oak wood (OW) extracts on Airén grapevines have on wine color, and must and wine glutathione, trans-GRP, trans-caftaric acid, and trans-p-coutaric acid content. Methods and results: These compounds were analyzed by HPLC. The results showed that, in general, foliar application of Airén vine-shoot extracts did not affect glutathione concentration, and the other treatments decreased it. AVS2013-50 and AVS2014 samples were characterized by a high content of glutathione and trans-GRP, while MVS2014 samples retain high levels of trans-caftaric acid. trans-p-Coutaric acid concentration decreased after AVS2013 treatment, meanwhile in the 2014 season all applications increased its content. The content of these compounds in the wines was similar to those obtained in the musts. OW2013 showed the lowest value of Abs 420, likely because this treatment decreased glutathione concentration in musts. Conclusions: The foliar applications of vine-shoots and oak extracts on Airén grapevines had a clear effect in reducing the wine alcohol degree and Baumé in case of grapes. This finding is interesting in the context of the current global warming change scenario. Although the two vintages studied were different, an improvement in the color quality was observed in both. The content of glutathione decreased from must to wine: the content in both matrices was lower in treated samples than in control samples, except for Airén extracts in both vintages. This means that glutathione is oxidized, avoiding the oxidation of other must and wine molecules. Significance and impact of the study: These findings are important in relation to revalorizing waste from the vineyard, and thus being able to improve the quality of the white wine in relation to the oxidation processe

[Aim] The study of elicitors in grapevines has focused on inducing resistance to diseases and improving phenolic and volatile composition of grapes and wines. Due to the importance of nitrogen compounds in grape quality, the aim of this work was to study the effect of methyl jasmonate (MeJ) applied to two grapevine varieties on grape amino acid content during two consecutive seasons. [Methods and results] Amino acids were analyzed by HPLC-DAD. The results showed that MeJ applications to Tempranillo grapevines decreased the concentration of certain amino acids during both seasons, but did not affect total amino acid content. Moreover, MeJ applications to Graciano grapevines increased the concentration of several amino acids during the second season. [Conclusions] The effects of MeJ on grape amino acid concentration were conditioned by variety and vintage. Significance and impact of the study: The importance of this work is to provide more information with respect to the effects of elicitors on grape quality for good viticultural management.