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Exposure to solar radiation is a determining factor of grape composition. Flavonol synthesis is upregulated by solar radiation leaving a fingerprint on flavonol profile. This study aimed to test the factors affecting flavonol accumulation and profile and their potential as an indicator to assess the overall exposure of red wine grape berry to solar radiation. We performed three experiments to study the response of flavonol accumulation and profile to (1) three different solar radiation exclusion treatments during berry development; (2) canopy porosity and leaf area index (LAI); and (3) spatial variability of water status, vigor and ripening and cultural practices in commercial vineyards. Results showed a strong relationship between global radiation, inverse dormant pruning weights or canopy porosity (inversely proportional to LAI) and % kaempferol or % quercetin. Furthermore, the increase in concentration of the above two flavonols was associated with a reduction of % myricetin. Total flavonol content, % kaempferol, % quercetin, and % myricetin had significant correlations with inverse dormant pruning weights, but these were less sensitive to over-ripening or water deficits. Flavonol profile was associated to site hydrology (wetness index) through changes in vigor, and to LAI; and responded to shoot thinning or fruit-zone leaf removal. These results support the reliability of the flavonol profile as an assessment parameter for studies aiming to discuss canopy architecture or the effect of solar radiation on grapevine berries.

Background and Aims: Under a surge of interest in the dual use of land, very scant information is still available about physiological and agronomical adaptations of the grapevine grown under agrivoltaics (AV) panels and their compatibility with light energy capture. Methods and Results: A setup of permanently horizontal AV panels mounted from veraison until harvest over Cabernet Sauvignon (CS) and Malvasia di Candia aromatica (MC) row sections was compared with an open‐field (OF) row section of the same cultivars. Uninterrupted diurnal and seasonal whole‐canopy gas exchange measurements were taken from August 9 to September 29. In contrast, total light interception, leaf gas exchange and water status, cluster temperature, and photochemical quantum yield of photosystem II (φPSII) readings were concentrated on August 13–14. Vegetative growth, yield components, ripening dynamics, grape and wine composition, and volatile and bound aromas were performed. Based on diurnal and seasonal direct and diffuse light measurements, panels cut incoming light by about 47%. In contrast, the reduction of the whole‐canopy net carbon exchange rate (NCER) and transpiration (T) was only 7%–9%. Canopy water use efficiency (WUE) was not significantly affected, although, in CS, WUE lowered when panels cast maximum shade over the central part of the day. With yield components not being affected, under AV, harvest was delayed by 17 and 12 days versus OF in CS and MC, respectively. However, while technological maturity was comparable in MC under OF and AV, the latter had lower monoterpenes and fermentative esters, which might hint at less floral and fruity notes. The rainy late season compromised grape maturity on the CS–AV vines, and the final wines were lighter in color and body. Conclusions: Under the specific panel’s configuration, the whole‐canopy gas exchange was minimally affected in front of a 47% light depletion. Panels caused a consistent ripening delay that was detrimental to free‐volatile wine components in MC. In contrast, it worsened grape and wine quality in CS primarily due to unfavorable late‐season weather.

Warm and semi-arid climates are characterized by rainfall scarcity, resulting in the frequent use of low-quality water for irrigation. This work was undertaken to study the effects of water stress and saline irrigation on yield and grape composition of Monastrell grapevines grafted onto 1103P rootstock. The experiment was carried out during three consecutive seasons in a commercial vineyard located in Jumilla (SE Spain) with a loamy-sandy soil. Rainfed vines were compared with five watering regimes including a Control, irrigated with standard water, and four treatments that combined two different schedules for irrigation initiation (pre- and post-veraison) with saline water obtained by adding two types of salts (sulphates and chlorides). Vines from treatments with more severe water stress (i.e., rainfed) showed lower yields and vegetative growth. Moreover, the Rainfed treatment clearly modified grape composition when compared with the Control treatment by increasing berry phenolic content. The application of saline water slightly affected vine performance and grape composition regardless of the type of salts added to the irrigation water. Indeed, the watering regime had a greater effect on yield, vegetative growth and grape composition than the use of different saline waters. Our results suggest that, in the mid-term (3 years), and with a vineyard soil with good drainage, the use of saline waters is not detrimental to vine performance, but does not improve grape composition. Further research is required to assess the long-term effects of saline water application, particularly in view of the important accumulation of chlorides and sodium in leaf tissues observed in vines watered with salty water at the last season of this experiment.

Summer pruning encompasses a series of operations typically performed on the grapevine during the growing season. This review provides an update on the research conducted over the last 20 years on the modalities and strategies of main summer pruning operations, which include shoot positioning and thinning, shoot trimming, leaf removal, and cluster thinning, with a special focus on their adaptation to climate change occurring in Mediterranean areas. Three main novelties emerged from the survey. First, due to a common need to shelter clusters against overheating and sunburn-related damages, shoot thinning and leaf removal are practices that are now being applied in a much more cautious and conservative manner. Second, the meaning of summer pruning is evolving because operations are being used as precious tools to direct ripening toward a desired direction rather than being received passively. Third, some operations, such as leaf removal, have disclosed very high plasticity, which means that, depending on the timing and modalities of the intervention, yield can be either increased or decreased and ripening anticipated or postponed. In an era where economic and environmental sustainability have to find a good compromise, cluster thinning is increasingly being depicted as an extraordinary operation that should be left to occasional occurrences of overcropping. Moreover, summer pruning is a tool through which growers can, to an extent, exploit the potentialities offered by climate change. For instance, the crop-forcing technique, under the different configurations of single and double cropping within the same season, has been trialed promisingly in several regions and cultivars. The principle of forcing is to unlock the dormant bud during the first year by removing at least the young organs present on the shoot within a time window between the end of the flowering and pea-size stages. In particular, when it is applied in a double-cropping mode, the preliminary results related to Pinot noir, Grenache, Tempranillo, and Maturana tinta indicate that two harvests separated by 30–50 days can be obtained, with the latter having superior quality in terms of a lower level of pH and higher levels of acidity, anthocyanins, and phenolics.

Vineyards are characterized by their large spatial variability of solar irradiance (SI) and temperature, known to effectively modulate grape metabolism. To explore the role of sunlight in shaping fruit composition and cluster uniformity, we studied the spatial pattern of incoming irradiance, fruit temperature and metabolic profile within individual grape clusters under three levels of sunlight exposure. The experiment was conducted in a vineyard of Cabernet Sauvignon cv. located in the Negev Highlands, Israel, where excess SI and midday temperatures are known to degrade grape quality. Filtering SI lowered the surface temperature of exposed fruits and increased the uniformity of irradiance and temperature in the cluster zone. SI affected the overall levels and patterns of accumulation of sugars, organic acids, amino acids and phenylpropanoids, across the grape cluster. Increased exposure to sunlight was associated with lower accumulation levels of malate, aspartate, and maleate but with higher levels of valine, leucine, and serine, in addition to the stress-related proline and GABA. Flavan-3-ols metabolites showed a negative response to SI, whereas flavonols were highly induced. The overall levels of anthocyanins decreased with increased sunlight exposure; however, a hierarchical cluster analysis revealed that the members of this family were grouped into three distinct accumulation patterns, with malvidin anthocyanins and cyanidin-glucoside showing contrasting trends. The flavonol-glucosides, quercetin and kaempferol, exhibited a logarithmic response to SI, leading to improved cluster uniformity under high-light conditions. Comparing the within-cluster variability of metabolite accumulation highlighted the stability of sugars, flavan-3-ols, and cinnamic acid metabolites to SI, in contrast to the plasticity of flavonols. A correlation-based network analysis revealed that extended exposure to SI modified metabolic coordination, increasing the number of negative correlations between metabolites in both pulp and skin. This integrated study of micrometeorology and metabolomics provided insights into the grape-cluster pattern of accumulation of 70 primary and secondary metabolites as a function of spatial variations in SI. Studying compound-specific responses against an extended gradient of quantified conditions improved our knowledge regarding the modulation of berry metabolism by SI, with the aim of using sunlight regulation to accurately modulate fruit composition in warm and arid/semi-arid regions.

Climate change strongly affects the wine industry, with impacts on grapevine vegetative behavior, grape primary and secondary metabolites and wine composition. The increase of ethanol is one direct consequence, creating the necessity of new oenological strategies. Nowadays, a challenging objective is the production of wines with reduced or removed alcohol content. Different strategies are developing, divided in pre-fermentative, fermentative and post fermentative. Those are also technologies able to reduce or remove alcohol content through physical methods. This review examines the effects of climate change on wine composition and winemaking processes, considering new technologies used to produce removed or low-alcohol-content wines. Il vino è una bevanda complessa e la sua composizione e qualità finale dipendono da numerosi fattori, tra cui il cambiamento climatico. La viticoltura e l'industria enologica sono fortemente influenzate dal cambiamento climatico, con impatti sul comportamento vegetativo della vite e conseguenze sui mosti d'uva e sulla composizione del vino. L'andamento crescente della temperatura ha influenza sulla fenologia e sul metabolismo della vite, così come sulla disponibilità di acqua, con effetti sui metaboliti primari e secondari dell'uva. Il cambiamento climatico ha creato la necessità di strategie enologiche per ottenere vini di qualità, in particolare temperature più elevate e stress idrico sono in grado di influenzare il contenuto di zucchero e acidi, influenzando, non solo il momento della vendemmia, ma anche la qualità del prodotto finale, con l'aumento dell'etanolo come una delle conseguenze dirette. Ciò influisce sul profilo sensoriale, riducendo le note fruttate e amplificando quelle sgradevoli. Inoltre, l'aroma e i loro precursori sono influenzati dal cambiamento climatico. Oggigiorno nella vinificazione uno degli obiettivi più impegnativi è la produzione di vini con un contenuto alcolico ridotto. Si stanno sviluppando diverse strategie, che considerano interventi nella fase pre-fermentativa, o durante la fermentazione alcolica, o sul vino dopo la fermentazione. Questa review esamina gli effetti del cambiamento climatico sulla composizione del vino e le possibili strategie nei processi di vinificazione per produrre vini a basso contenuto alcolico.

The adoption of winter cover crops (CCs), to be terminated in spring, is gaining popularity in temperate climate viticulture. We evaluated the effects of two novel termination practices—interrow rolling (R) and subrow mulching (SRM)—on vine performance and physiology of Barbera grapevines over 3 years, comparing them to a standard termination practice (green manuring, GM) and a control (C) consisting of alternated tilled and vegetated interrows. For each termination type, we used a cereal‐based (Humusfert, H) and a more balanced (Stratus, S) seed cocktail. Data collection included CC biomass, seasonal soil and leaf water potential, leaf assimilation (A) and stomatal conductance ( g s ) rates, vine vigor, yield, and grape composition at harvest. R caused a 31% reduction in pruning weight compared to C. Soil water potential at 30‐cm depth, as well as leaf A and g s , was more limited than in the other treatments and, in S‐R, ripening was delayed. R performances might suffer from increased surface evaporation and reduced precipitation effectiveness due to the thick mulch layer. Both SRM treatments ensured a thick mulch layer (over 1 kg of desiccated grass/m 2 ), which effectively controlled weeds when placed under the row. SRM did not impact vine vigor and yield; however, using the S mix slightly delayed final ripening. The presence of a thick, dead mulch layer under the row improved soil water potential (Ψ SOIL ) at 30‐ and 60‐cm depths compared to all remaining treatments that shared a mowed under‐the‐trellis strip. Seasonal dynamics of absolute Ψ SOIL show that when Ψ SOIL in the C plot fell below −0.2 MPa, Ψ SOIL was significantly higher (less negative) in H‐SRM than in S‐SRM. This was also associated with average reductions of 31.3% and 37.1% in A and g s rates in S‐SRM compared to H‐SRM, respectively. The higher fresh biomass yielded by the more balanced mix (S) may relate to increased soil water depletion, especially during the pre‐termination phase. Both C and GM treatments showed similar vine performance; however, C was significantly limited in leaf gas exchange compared to others. C does not benefit from any mulching effect, and a competitive native grass cover persists every second interrow during the dry and harsh summer season.

Yield components and fruit composition of ‘MidSouth’, an interspecific hybrid bunch grape (Vitis spp.) with relatively low total soluble solids and high titratable acidity, was evaluated in south Mississippi to determine if treatments consisting of early pruning, early pruning with pre-bloom leaf removal, normal pruning with post-fruit set leaf removal, or normal pruning in one study, or post-fruit set leaf removal, post-fruit set shoot thinning, or neither leaf removal nor shoot thinning in a second study could improve these qualities. Early pruning with leaf removal reduced berries per cluster, cluster weights, yields, and Ravaz index. Early pruning treatments had inconsistent results from year to year, and normal pruning treatments were not often significantly different. Shoot thinned vines had lower yields and Ravaz index and higher total soluble solids. Second study leaf removal vines had lower juice pH in 2020 and lower yield per vine in 2021. These findings show that ‘MidSouth’ can be altered by these practices, but they did not appear to sufficiently alter ‘MidSouth’ quality. Thus, early pruning with or without leaf removal, normal pruning with leaf removal, and shoot thinning are not recommended for ‘MidSouth’ in south Mississippi, and normal pruning without these practices should be continued.

Low total soluble solids and high titratable acidity limit MidSouth use as a varietal red wine grape. While canopy management practices were reported not to have enough of an effect on these primary metabolites, they could potentially improve MidSouth secondary metabolites, broadening its potential as a wine grape. Two studies assessed the effects of different canopy management treatments on monomeric anthocyanin pigments and total phenolic content in MidSouth juice and wine. The first study compared early pruning, early pruning with leaf removal, normal pruning with leaf removal, and normal pruning. Early pruning with leaf removal showed higher total phenolics in juice and wine in 2021 but lower levels in 2020. The second study evaluated leaf removal, shoot thinning, or neither leaf removal nor shoot thinning. Leaf removal resulted in higher anthocyanins and total phenolics in 2021 juice, while shoot thinning increased total phenolics in 2021 juice and both anthocyanins and phenolics in 2021 wine. Shoot thinning demonstrated the most consistent improvement in phenolic content. MidSouth grapes can produce a range of wine phenolic content, depending on canopy management and postharvest treatment. Further investigation is needed to understand yearly variations and optimize MidSouth for regional red wine production.

Climate change and unsustainable agricultural practices are triggering land degradation in semi-arid Mediterranean regions. Organic amendments, such as mulching materials, have shown promising potential to mitigate these impacts by improving soil chemical, physical, and biological properties, while enhancing grapevine growth and productivity. This study evaluated the effects of wheat straw mulch (M) and wheat straw combined with biochar (MB), together with vineyard topography (bottom vs. top), on grape chemical and phenolic composition in four Vitis vinifera L. cultivars (Syrah, Trincadeira, Alicante Bouschet, and Antão Vaz) grown in the Alentejo wine region. Grapes were sampled separately at top and bottom topographic positions, and classical and phenolic parameters were analyzed. The application of M and MB significantly modified must composition, mainly through changes in nitrogen and sugar levels across topographic positions. Only MB exhibited stronger effects, enhancing must quality, while MB and M reduced bottom–top variability. Similar patterns and positional effects were observed for phenolic and color parameters. Both organic treatments lowered total monomeric anthocyanin concentrations, although positional differences with wheat straw mulch were found. The results highlight that combining soil management with topography and variety response can optimize grape phenolic composition and promote sustainable viticulture through targeted, site-specific mulching strategies.