Lucia Giordano

Excessive flavonol accumulation in berry skin under high solar radiation may increase the risk of quercetin-related instability in red wines. In 2024, a field trial was conducted on ‘Sangiovese’ grapevines grown in a non-irrigated vineyard in central Italy to evaluate the effects of a novel β-carotene-based bio-protector (NBP). The product was applied once at veraison at 1% or 2% (v/v). At harvest, yield components and technological maturity parameters were assessed; berry-skin phenolics and carotenoids were quantified by HPLC, and the expression of CHS, CHI, FLS, and a MYB regulator was quantified by RT-qPCR. NBP application did not significantly affect yield components or must composition. In contrast, both NBP concentrations reduced quercetin-3-O-glucoside and quercetin-3-O-glucuronide, as well as kaempferol derivatives, while flavan-3-ols were unaffected. Lutein content increased in treated berries, reaching the highest levels in 2% NBP vines, whereas β-carotene remained unchanged. Consistent with these findings, gene expression analysis showed downregulation of flavonol-biosynthetic transcripts, with FLS exhibiting the strongest repression. Overall, a single NBP application at veraison effectively limited flavonol accumulation under warm, high-radiation conditions without compromising yield or ripening. Differences between the two NBP concentrations were more evident for lutein accumulation than for flavonol reduction, suggesting distinct metabolic responsiveness of these pathways to the treatment.

The protection of leaves from photoinhibition and berries from dehydration and sunburn has become an increasingly important objective in response to the rising frequency and intensity of heat waves worldwide. This research investigated the effect of a white nonwoven geotextile sheet (TNT) installed in the fruiting zone in the white cultivar ‘Verdicchio’ (Vitis vinifera L.) during critical summer periods with the aim of protecting leaves and berries from extreme heat. The study was conducted over two seasons (2020–2021) in a rainfed vineyard in central Italy using a randomized block design. Physiological and yield parameters were recorded. Vines protected with TNT did not show any changes in net photosynthesis, stomatal conductance, and water use efficiency, compared to unshielded vines. However, TNT reduced leaf temperature and increased berry total acidity and malic acid concentration while reducing sugar content, leading to wines with higher freshness and reduced alcohol levels. The use of TNTs shows significant potential as a practical tool for viticulturists to mitigate the effects of excessive heat, allowing for better management of berry ripening and ultimately improving final wine characteristics. Additionally, TNT is economically feasible, especially if applied only to the afternoon-exposed side of the canopy, and its cost can be amortized, especially in vineyards affected by frequent heat waves and/or dedicated to the production of premium wines.

Direct sunlight on berries during ripening enhances flavonoid accumulation in the skin, acting as a defence against UV damage and lipid peroxidation. However, these flavonoids, particularly quercetins, influence bitterness, astringency, and deposit formation in wines. This study evaluated the effectiveness of a new bio-protector (NBP), composed of β-carotene and α-pinene, in reducing flavonol levels in grape skins across cultivars and locations, applied by spraying the basal part of the canopy, completely wetting all leaves and grapes. In 2023, trials were conducted in non-irrigated vineyards with Sangiovese and Trebbiano Toscano in Umbria, and Grillo and Carricante in Sicily. In 2024, Merlot and Grenache in South Australia were included. Thirty vines per vineyard were treated with NBP (2 % in water) at veraison (BBCH 81), while 30 control vines received water. In two vineyards, basal leaf removal was performed a day before NBP application. Gas exchange measurements, yield components, grape composition, and berry phenolic and carotenoid profiles were recorded. NBP-treated leaves showed reduced photosynthesis, transpiration, and stomatal conductance but no impact on yield, cluster weight, or berry weight. NBP delayed technological ripening, reducing sugar accumulation and increasing acidity. Flavonol profiles revealed quercetin-3-O-glucoside (60–74 %) and quercetin-3-O-glucuronide (28–38 %) as dominant, with Sicilian cultivars showing 10 times lower flavonol levels than central Italian cultivars. Basal leaf removal increased quercetin and kaempferol by three–four times. NBP significantly reduced flavonol accumulation in berry skins across cultivars and sites, delaying ripening without causing dehydration or sunburn damage. This could reduce wine bitterness and astringency and allow later harvests, especially in red cultivars. Exogenous β-carotene application did not increase berry skin carotenoids, but the correlation between flavonol accumulation and irradiance was confirmed. NBP’s potential to mitigate the impact of rising temperatures on grape and wine quality is promising.

Background and Aims: Global warming is driving increased heat accumulation and longer growing seasons, making it feasible to ripen two crops in a single season, even in temperate regions where grapevines experience winter dormancy. Methods and Results: A 2‐year study on Cabernet Sauvignon in South Australia evaluated vine responses to a “double cropping” technique aimed at producing two consecutive crops (primary [P] and forced [F]) within the same season. The forced crop was achieved by breaking bud dormancy through severe trimming at the groat‐size berry stage; retaining four, six or eight main leaves on the shoot (F4, F6, F8); and concurrently removing any developing laterals. These treatments were compared to an unforced control (C). Vine performance was assessed through phenology, vegetative growth, yield components, vine balance indices and grape composition at harvest. In the 2022–2023 season, the response to forcing was faster (13 days) and more active (0.69 forced shoots/total shoots) than in the 2023–2024 season (19 days and 0.47 forced shoots/total shoots, respectively). Reactivity to forcing tended to decrease at F8 compared to F4 and F6. On average, the forced leaf area (LA) constituted 59.2% of the total LA. Across all F treatments, the total yield per vine was 11.6% higher than C, with the forced crop contributing 36.1% of the total yield. Forced shoot bunches were consistently smaller and looser than those on the P shoots and harvest of the second crop occurred 56–60 days later. Forcing significantly delayed the ripening of the primary crop compared to the control, yet fruit in F treatments reached a relatively high TSS (23.7–24.1°Brix) while maintaining higher TA and lower pH, indicating a desynchronisation of sugar and acid ripening. Seasonal variation strongly influenced anthocyanin and phenolic accumulation: in 2022–23, levels were highest in F treatments, even compared to the control; in 2023–2024, they were comparatively low. Since LA/Y remained adequate, it is hypothesised that late‐season microclimate conditions are likely the primary factor in berry pigmentation outcomes. Conclusions and Significance of the Study: Overall, this technique shows promise for improving vineyard profitability by increasing total yield and offering opportunities for the diversification of wine styles. Work is underway to develop mechanised approaches for broader adoption.

The aim of this study was to characterize the ampelographic and genetic profiles of Vitis vinifera L. cv. Nero Antico di Pretalucente and to describe the grape-borne fungal communities. The oenological characteristics and the aroma profile of wine obtained by spontaneous fermentation were also investigated. Microsatellite profiles and ampelographic traits indicated that this cultivar presented a unique profile, and therefore it can be considered a cultivar in its own right and autochthonous of Gessopalena village. Next-generation sequencing analysis revealed that Aureobasidium spp. was the main genus detected on grapes. At the species level, Aureobasidium pullulans was the main species, followed by Alternaria alternata. Wines were characterized by a final ethanol content of 12.75% (v/v), a pH of 3.4, a volatile acidity lower than 0.6 g/L, a content of glycerol of 8.56 g/L, and a concentration of polyphenols and anthocyanins of 977 GAE/L and 266 mg/L, respectively. The intensity and tonality of the wine as well as the active odor compounds found were described. The results obtained could improve the knowledge concerning the agronomic traits and the wine obtained from this ancient and autochthonous grapevine variety cultivated in a foothill area, in order to offer consumers a wine with unique traits.

The double pruning technique on Sangiovese vines, based on pre-pruning in February and finishing in April, induced a delay of bud break, which is an approach to avoid spring frost damage. The field experiment was conducted on Sangiovese vines mechanically spur-pruned during dormancy in February and manually finished post budburst to test the potential of ‘double-pruning’ approach to prevent the spring frost damage. This technique, associated with the finishing performed when the apical shoots on the mechanically-shortened canes were about 10 cm long, allowed to keep the basal buds in a dormant phase for almost 15 days, extending the resistance period against the spring frosts, particularly important for the cultivars characterized by early bud-break. Yield reduction per vine was -22% due only to the incidence of unsprouted buds, while the grape ripening profile was delayed with an increase of acidity and phenols and a decrease of pH and soluble solids.