Australian Journal of Grape and Wine Research最新文献

Vibrational mating disruption (VMD) is a promising strategy to control Scaphoideus titanus populations in vineyards, and it is based on the prolonged application of a species-specific disturbance vibrational signal (DVS) on grapevines. Plants can react by different transcriptional, physiological, and morphological changes, according to the source and type of mechanical stimuli, but no information is available on possible side effects of DVS on grapevine plants. This study aimed to investigate grapevine response to DVS during VMD exposure under field and greenhouse conditions. No negative effects were observed on vine productivity, berry characteristics, and grape quality parameters in two consecutive seasons under field conditions. Chlorophyll, flavonol, and anthocyanin content, nitrogen balance index, stomatal conductance, electron transport rate, and leaf vapor pressure deficit were comparable in DVS-treated and control plants under field and greenhouse conditions. Moreover, no modulation of genes related to defense, growth, and secondary metabolism was found in the leaves of DVS-treated plants, indicating no negative impacts of VMD on grapevine physiology. The only observed difference associated with DVS treatment was an increased internodal length under field and greenhouse conditions with partial stimulation of shoot length. Although further studies are required to clarify the mechanism of internodal length stimulation, these results support the absence of negative effects of VMD on grapevines, encouraging its further application in commercial vineyards.

Climate change increasingly threatens grape acidity, a key determinant of wine quality and stability, through intensified drought and warming. This study develops an acidity-focused, climate-based approach to characterise cultivar-specific responses to climatic dryness in a Central European wine region. Long-term observational data from the Eger Wine Region (Hungary) were used to quantify relationships between the dryness index (DI) and titratable acidity across seven Vitis vinifera cultivars through linear regression analysis. Two indicators are introduced: The dryness index for balanced acidity (DI_ACBal), which describes the climatic dryness at which balanced acidity, is maintained and the optimum water demand (OWD), a cultivar-specific estimate of climatic water availability, is required for acidity preservation. Cultivars differed consistently in their responses to climatic dryness (R² = 0.65–0.81), with low-OWD varieties maintaining acidity under drier conditions, whereas high-OWD cultivars required greater water availability. Scenario-based DI projections indicate a declining probability of balanced acidity toward the late 21st century without adaptation. This approach supports cultivar selection and vineyard water management under a changing climate.

The rising demand for functional foods has increased interest in natural additives that enhance the nutritional and sensory qualities of traditional products. This study is the first to investigate the enrichment of Cabernet Sauvignon wine with Arthrospira platensis (AP), a filamentous cyanobacterium, to improve its nutritional and functional attributes. Grapes harvested from Gaziantep Province (Türkiye) in 2022 were used to produce four wine variants: a control (0% AP) and three treatments with 0.1%, 0.2%, and 0.4% AP. AP addition significantly affected physicochemical properties, bioactive composition, and sensory attributes. AP-enriched wines exhibited a gradual increase in pH over time, unlike the control. Total phenolic content rose sharply after opening, reaching 4107.9 mg·GAE/L in the 0.4% AP wine, while the control declined. Antioxidant capacity improved, with the highest DPPH radical scavenging activity (6.12 mg·TE/mL) in the 0.4% AP treatment. Concentrations of key phenolics—including gallic acid, resveratrol, quercetin, procyanidin, and chlorogenic acid—were significantly elevated. Principal component analysis further distinguished AP wines from the control, highlighting AP’s role in altering wine composition. Sensory evaluation revealed that 0.1% AP improved flavor, aroma, appearance, and color, whereas higher levels slightly reduced acceptance due to intense pigment and aroma characteristics, though scores remained within acceptable limits. These findings suggest that AP shows strong potential as a natural fortifying agent, improving the nutritional, functional, and sensory qualities of wine.

In response to a warming and drying climate, viticulture at higher elevations could be a viable adaptation strategy for the wine industry. Nevertheless, our knowledge about the optimal water management in mountain vineyards remains limited. This study evaluated the effect of drought stress on two grapevine cultivars (Sauvignon Blanc and Chardonnay) under irrigated and rainfed conditions. The research took place in the mountainous region of South Tyrol in northern Italy. Soil-water status, several plant-based physiological stress indicators, yield components, berry quality, and wine sensory attributes were monitored across two growing seasons. Drought stress varied in timing and intensity. In 2021, a 10-day drought occurred during berry set, while in 2022, a more severe drought coincided with veraison and was combined with a 9-day heatwave. Reduced soil-water availability caused growth inhibition and impaired photosynthetic activity, particularly in 2022. Conversely, the mild to moderate water deficit during berry set caused a greater reduction in berry size and weight, and consequently in yield, than the more severe water deficit at veraison. As for berry quality traits, drought stress affected berry soluble solids accumulation, but not pH or titratable acidity. Furthermore, sensory analysis revealed distinct differences across vintages and cultivars. Wines from rainfed vines displayed enhanced hedonistic attributes (e.g., complexity, fullness, and length), particularly when the stress occurred early during the season. Generally, despite comparable stress exposure, Sauvignon Blanc vines were more drought-sensitive, showing greater growth inhibition, decreased photosynthetic activity, substantial yield loss, and altered wine sensory profiles. Chardonnay, conversely, seemed more resilient to drought conditions, showing no discernible differences between rainfed and irrigated wines. In conclusion, this study reveals varying levels of drought tolerance between the two cultivars across two seasons. These findings may help develop cultivar-specific irrigation schedules for mountain vineyards, enhancing water conservation, preserving yields, and ultimately achieving the desired wine quality.

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 1 to develop mechanised approaches for broader adoption.