Australian Journal of Grape and Wine Research最新文献

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/m²), 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.

A two-year study was carried out to investigate the effects of eight rootstocks belonging to different crosses within Vitis genus on the performance of cv Glera grown in Northeastern Italy. Vegetative growth, yield, vine water status, and chemical parameters of berry juice were analyzed with the aim of identifying more suitable genotypes for adapting to climate change conditions. During the two experimental years, different amounts of precipitation were recorded, with warmer and drier conditions observed in 2022; consequently, the interaction effects between rootstocks and year (RxY) were significant for most of the parameters analyzed. Overall, the Vitis berlandieri × Vitis riparia genotypes (SO4, K5BB, and 420A) showed the best agronomic performance, although suffering from dry conditions in the warmer vintage. Vitis berlandieri × Vitis rupestris genotypes (1103P in particular, but also 140Ru and 110R) exhibited the best tolerance to the water stress conditions that characterized the 2022 season, maintaining acceptable yield and quality. Finally, a wide variability in responses was observed among Vitis riparia × Vitis rupestris genotypes in the investigated area; 101-14 showed a higher yield and number of clusters, while Schwarzmann was the least performing, with lower yield and lower acidity of the juice at harvest; moreover, the latter rootstock showed an anticipated budbreak, making it more susceptible to late frosts. This study revealed that Glera physiological and agronomic responses may vary greatly in response to the use of different rootstocks. Some genotypes showed the ability to confer to this variety a greater adaptability to high temperature and drought. These findings provide valuable insights for the selection of rootstocks capable of sustaining yield and preserving quality in the Glera variety under the projected climatic changes in the study area.

Red wine cap management during alcoholic fermentation influences the extraction of phenolic compounds from grape solids and in turn affects oxygen consumption, oxidation–reduction potential (ORP), and must homogenization. Tailoring cap management protocols to influence these processes is essential for targeting wine style based on varietal and fruit composition. Herein, Pinot noir and Petite Sirah wines were produced with five cap management protocols, namely, pumpovers (POs), punchdowns (PDs), no cap management (NoCapMgmt), air mixing (AirMix), and nitrogen mixing (N₂Mix). ORP of AirMix wines reached peaks of 340 mV and 240 mV in Pinot noir and Petite Sirah, respectively, while N₂Mix wines were consistently below −50 mV during alcoholic fermentation. At pressing, treatments deemed oxidative, that is, AirMix, PO, showed the lowest concentrations of acetaldehyde, and treatments deemed reductive, that is, NoCapMgmt, N₂Mix, the highest. Relative to PO wines at pressing, PD wines showed 22% increases in total phenolics in Pinot noir but insignificant differences in Petite Sirah. PD increased flavan-3-ol concentrations in both varietals. After 8 months of bottle aging, NoCapMgmt contained > 50% more esters than PD wines in both varietals. Ethyl n-decanoate and isoamyl acetate exhibited the highest odor activity values (OAVs) in all wines. Ethyl n-decanoate ranged from 121 (NoCapMgmt) to 69 (AirMix) in Pinot noir and 186 (NoCapMgmt) to 103 (PD) in Petite Sirah. Isoamyl acetate ranged from 52 (NoCapMgmt) to 20 (PD, AirMix, N₂Mix) in Pinot noir and from 174 (NoCapMgmt) to 95 (AirMix) in Petite Sirah. In both varietals, AirMix wines showed decreased astringency and increased red fruit character, while N₂Mix wines had higher color saturation and no reductive aromas despite consistently low ORP during alcoholic fermentation. Present results provide winemakers with tools to optimize fermentation kinetics and labor costs, selectively extract phenolic compounds, and produce wines of targeted style and sensory profiles in varietals with contrasting phenolic profiles.

In response to increasingly hot and dry summers driven by climate change, grapevines (Vitis vinifera L.) can utilize adaptive mechanisms that often prioritize survival over yield and grape quality. The efficiency of the vine canopy, particularly in terms of gas exchange and net assimilation, declines with water scarcity, underscoring the importance of mitigating strategies such as emergency irrigation. However, in Mediterranean vineyards, water shortages often render irrigation impractical. An alternative approach is the application of minerals, such as zeolites, to mitigate the negative effects of summer stress. This study aimed to evaluate the physiological, vegetative–productive, and qualitative effects of chabazite-rich zeolite treatments on potted grapevines subjected to both water and heat stress, and on field-grown vines exposed only to heat stress. The research was conducted over a 3-year period (2021–2023) on Sangiovese grapevines, divided into two distinct trials: the first on potted vines (2021) and the second on field-grown vines (2022–2023). The potted trial involved 12 plants placed on lysimeters, subjected to water restriction (50% restitution of water lost through transpiration), and divided into two treatments: water stress vines (WS) and WS vines treated with natural zeolite (WS + ZEO). The field trial involved 24 nonirrigated plants with two treatments: untreated control (WS) and zeolite treatment (WS + ZEO). Microclimatic conditions were monitored during ripening, and the effects of zeolite were assessed in terms of canopy physiology, yield, sunburn damage, and grape composition. Grapes from the field trial vines were microvinified, and the resulting wine color was analyzed twice, after 3 months and 1 year. The results showed that zeolite treatments effectively reduced canopy temperature by two degrees Celsius, enhancing gas exchange efficiency and photosynthetic activity in potted vines. In field-grown vines, these treatments significantly improved grape composition, particularly boosting total anthocyanin levels by 19% in the berries and 10% in the resulting wine, compared to the untreated control. In conclusion, zeolite-based treatments appear to be a valuable tool for improving the productive performance of Sangiovese in environments characterized by multiple summer stresses.

Background and Aim: The single-high-wire (SHW) system is a very productive trellis system suitable for the mechanization of cultural practices. It has been proposed as an adaptation strategy for mitigating the effects of global warming in warm and hot wine regions. The aim was to study the impact of different pruning severity treatments [16, 24 and 32 bud m⁻¹ of productive cordon and simulated mechanical pruning (SMP)] on the performance of a Malbec SHW vineyard in a hot and arid region.

Methods and Results: The vineyard performance was assessed by means of characterizing the canopy architecture, winter trunk reserves, yield, fruit and wine composition. The variation of the pruning severity affected the architecture of the shoots but did not affect the canopy total leaf area. Lower pruning severity levels increased the number of smaller shoots and decreased the proportion of the leaf area corresponding to secondary shoots. After 3 years of treatment, bud fruitfulness and winter wood reserves were not adversely affected by lowering pruning severity. In general, it was observed that the lower the pruning severity, the higher the yield. Indeed, the lowest pruning severity level (SMP) increased the number of smaller clusters with fewer and smaller berries. Moreover, we found that pruning severity did not affect the berry’s anthocyanin and volatile organic compound profiles. Additionally, reducing pruning severity slightly decreased soluble solid accumulation and alcohol content of wines without affecting colour and acidity.

Conclusion: The cultivar Malbec trellised to the SHW system in a hot and arid region is able to self-regulate between vegetative and reproductive growth, attaining maximum yield without forfeiting quality at low pruning severity levels such as it is imposed by mechanical box pruning.

Significance of the Study: These findings support growing and managing Malbec on the SHW system with mechanized pruning in hot and arid regions.

This study compared two sets of soil samples. One set was from a sheep paddock, the other set from an adjacent vineyard. Conventional agronomic soil tests showed that both sets of soil shared a common structure and nutrient base. However, there was more microbial biomass in the vineyard soil samples (p < 0.001). Most of this difference was due to increased fungal biomass in the vineyard (53% more total fungi biomass, p < 0.001), including mycorrhizal species (159% more mycorrhizal fungi biomass, p < 0.001). The study deployed a series of 10 electronic noses, each with six different gas sensors, on both sets of soil. The electronic noses detected higher levels of volatile organic compounds from the vineyard soil (p < 0.001), thus establishing a strong positive correlation with the microbial biomass results.

Background and Aims: The main wine-producing areas of the Iberian Peninsula are affected by Xylotrechus arvicola, an insect pest species which causes structural and biomechanical damage in vineyards (Vitis vinifera) due to the ingestion of vascular tissues.

Methods and Results: To evaluate the mechanical properties of wood affected by X. arvicola larvae, we performed compressive and flexural tests. Damaged trunk wood samples presented a larger damaged section (DS) than that in branch wood samples. The compressive strength × DS interaction yielded significant differences, which suggest a stronger relationship between DS and loss of resistance in branches. Both loading (Time 1) and breakage (Time 2) times decreased as DS increased for branch wood samples (fresh and dry); however, significant differences were observed in Time 2, suggesting that, in branches, DS causes greater fragility. Maximum bending moment was higher in undamaged branch wood samples than that in damaged ones (dry or fresh); this demonstrates that undamaged wood fibers are less resistant than those attacked by X. arvicola larvae.

Conclusions: The grape weight and/or the vibration applied by harvesting machines in affected wood branches can produce production losses and cause serious economic losses to the wineries or owners of the affected vineyards and, therefore, could be recommended to remove annually the affected parts to avoid the accumulation of dead wood due to the ingestion of its vascular tissues at the first insects attacks.

The change in consumption habits, the need for product differentiation and the transition to eco-sustainable wine production have led to the adoption of alternative packaging solutions, moving beyond the traditional glass bottle. This study employs experimental auctions with a sample of 100 participants to assess consumer willingness to pay for both bag-in-box and traditional glass bottle packaging. Using statistical tests and regression analysis, we find that consumer preferences for wine packaging formats significantly influence purchasing decisions and perceptions of product quality. Notably, consumers show a lower willingness to pay for the same wine when packaged in a bag-in-box than a bottle, and taste does not influence the willingness to pay. Moreover, the preference for bottled wine seems to be socially influenced. This study enriches the understanding of consumer behaviour regarding packaging preferences and provides actionable insights for the wine industry, retailers, policymakers and consumers.

Background and Aims: Viticulturists and winemakers have a considerable interest in understanding the influence of climate, soil, viticultural and winemaking practices on wine sensory outcomes—that is, understanding the terroir concept, which is important for regionality and claims of product distinctiveness. In this investigation, an empirical study of grape and wine composition, including sensory evaluations, was used to inform the delineation of subregional areas of the Barossa Zone geographical indicator (GI).

Methods and Results: A spatiotemporal investigation of Shiraz was undertaken with vineyard zones selected to exemplify maximum heterogeneity within a site. Objective measures of vine performance and grape and wine composition were clustered using the k-means approach, and up to three clusters of vineyard sites were evident within the dataset. Clusters were associated with vineyard elevation and thus growing temperatures. The most important measures of composition defining each cluster were the volatiles ethyl octanoate, diethyl succinate, 1,8-cineole and 3-methyl butyl acetate in grapes. Sensory attribute intensity differences were apparent for wines from some subregions, and projection of the important attributes for clusters defined in this study to key sensory differences shows a high variance in composition related to sensory features from year to year. The spatial outcomes of clusters for vineyard sites align with of some outcomes of prior clustering approaches using data-rich sources for precision agriculture.

Conclusions: Subregional zones within the Barossa can be identified where sufficient variations between vineyard elevations exist that impart grape compositional differences, which in turn translate into wine sensory attributes.

Significance of the Study: This empirical study provides some evidence for regionality within the Barossa with up to three subregions identified in some vintages.

Background and Aims. The Mediterranean climate has been traditionally favorable for winemaking and irrigation practice has been historically avoided and even forbidden, but current productive scenarios are suffering radical changes because of global warming. Therefore, seeking sustainable approaches to improve water availability is key to obtaining high-quality wines and maintain its style, without affecting yields. Methods and Results. Here, we aim to evaluate the effect of irrigation in Merlot vineyards, on grapes production and quality, and also on wine acceptability. Field-grown grapevines from cv. “Merlot” were subjected to two different water supplies in the field: (i) nonirrigated plants and (ii) irrigated plants with 50% of crop evapotranspiration, from veraison to commercial harvest. We assessed water stress markers such as leaf relative water content, leaf hydration, and the maximum efficiency of photosystem II photochemistry, as well as grape and wine quality parameters, wine acceptability, and preference with a panel composed of 100 participants. Furthermore, we performed a systematic review study for comparison, including 9 published reports on Merlot grapevines subjected to different water regimes, oriented to improve irrigation decisions, yield, and/or quality. Results showed that half water supply on grapevines not only induced an increase in the volume and weight of grapes, but the resulting wines had a lower total acidity and showed more desirable chromatic properties, increasing colour intensity and hue, and decreasing brightness. Sensory analysis revealed that 63% of the untrained panel preferred wines from the irrigation treatment. Integrating previously reported data, it is observed that water scarcity is favorable for quality only when compared with fully irrigated vineyards. Conclusions. It is concluded that a half irrigation can be enough to improve grape quality under Mediterranean conditions, without affecting yield components and enhancing sensory characteristics that can improve wine acceptance by consumers. Water management approaches to sustainably provide this extra amount of water to irrigate field-grown grapevines under the current context of climate change are discussed. Significance of the Study. The present study’s findings provide valuable information regarding water management in Mediterranean vineyards and its effects on the suitability of these areas to maintain high-quality wine production.