Australian Journal of Grape and Wine Research最新文献

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.

Grapevine pruning is an agronomical operation required to regulate growth and yield, improve fruit quality, and maintain plant health and vigour. However, the intensification of the crop in the last decades, driven by efforts to increase productivity and decrease costs, has led to reduced attention to this operation. The aim of this study was to investigate whether different pruning styles during the first years of vineyard training affect grapevine development. Three pruning styles were followed in a newly planted cv. “Tempranillo” vineyard for four consecutive pruning seasons: (i) respectful (RESP), where pruning cuts were always made leaving protection wood between the cut and vine perennial structures, and the preferential sap flow path was chosen; (ii) aggressive (AGGR), where no protection wood was left and, when possible, the nonpreferential sap flow path was followed; and (iii) winegrape grower (WIN), where the common practices used in the area were followed, which corresponds to an intermediate style between RESP and AGGR. In general, the RESP style increased the vegetative development compared to WIN and AGGR styles over the years and produced a higher yield in the first production year, although the intensity of the effect was not the same in the two vineyards considered. This was the first effort to systematically assess the effects of respectful pruning techniques on vine vegetative growth and demonstrate scientifically its impact.

Copigmentation is a noncovalent interaction between anthocyanins and colourless copigments that stabilises the anthocyanin-coloured forms by protecting them against water attack. Copigmentation can be responsible for almost half of the colour observed in young red wines. It has been reported that flavonols are the most effective wine copigments, but studies on the influence of the structure of these copigments on the magnitude of copigmentation are scarce. However, flavonol profiles change with grape variety and can condition the colour of the resulting wines. In addition, mannoproteins (MPs) have been reported to interact with flavonoids, which, consequently, might affect the flavonol-anthocyanin interaction. The objective of the present study was to evaluate the ability of five grape flavonols (isorhamnetin, kaempferol, quercetin, syringetin, and myricetin 3-O-glucosides: I-3-glc, K-3-glc, Q-3-glc, S-3-glc, and My-3-glc) by conventional spectrophotometric measurements and CIELAB analysis to copigment with malvidin 3-O-glucoside (mv-3-glc) in the absence or presence of five different MPs (binary and ternary model systems). Among the tested flavonols, I-3-glc was the most effective copigment, whereas K-3-glc was the least one. S-3-glc and Q-3-glc showed intermediate effectiveness, but that of S-3-glc was closer to I-3-glc and that of Q-3-glc to K-3-glc. These results point out that the presence of methoxyl groups in the B-ring of the flavonol increases copigmentation magnitude. The participation of My-3-glc in copigmentation interactions seemed to be hindered by its colloidal instability. Regarding the tested MPs, they did not provoke a direct copigmentation effect, but were able to modify the magnitude of the interaction between the flavonols and the anthocyanin and, in some cases, the colloidal behaviour of coloured aggregates formed over time. Finally, the results of the additional HPLC-DAD analyses point to a greater protection of the anthocyanin against degradation in the model systems where the magnitude of copigmentation was greater.

Background and Aims. Rootstocks are widely used in the viticulture industry to manage biotic stress, particularly the infestation of phylloxera, and to improve tolerance to abiotic stress. Grafting grapevines to rootstocks affects the berry quality and may influence the wine composition. This project investigated the impacts of 14 different rootstocks on the berry and wine chemical properties, phenolic profile, and volatile profile of grafted Vitis vinifera L. cv Pinot noir MV6. Methods and Results. This study was conducted at a commercial vineyard located in Mornington Peninsula, Victoria, Australia. The scions of V. vinifera L. cv Pinot noir clone MV6 were grafted onto 14 rootstocks, including 101-14 Millardet et de Grasset (101-14 Mgt), 1103 Paulsen, Selection Oppenheim (SO4), 110 Richter, Schwarzmann, 5C Teleki, 3309 Couderc (3309C), Merbein 5489, Merbein 6262, Merbein 5512, C20, C29, C113, and C114, with own-rooted vines acting as the control group. Berries were collected at harvest in the 2020 and 2021 vintages for small-scale winemaking. The pH, titratable acidity, phenolic content, and antioxidant activity of both the berries and wine were measured using conventional chemical analysis. The phenolic composition of the wine over the two vintages was identified and quantified by high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (HPLC-QTOF-MS/MS) and HPLC with diode-array detection (HPLC-DAD). The volatile composition was measured by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Grafting Pinot noir onto 3309C caused a reduction in the berry and wine pH without affecting the titratable acid. Several rootstocks, such as 1103 Paulsen, SO4, Schwarzmann, and 5C Teleki, reduced the total phenolic content (TPC) in both the berries and wine of Pinot noir. Conversely, Merbein 5489 increased the berry and wine TPC by 15% and 63%, respectively, compared to ungrafted Pinot noir MV6. A similar tendency was also found in the condensed tannin content (CTC), where Merbein 5489 increased the berry and wine CTC by 35% and 112%, respectively, compared to ungrafted vines. Several rootstocks, such as 3309C and Merbein 6262, increased the wine anthocyanin content (especially malvidin 3-O-glucoside), which may contribute to enhanced colour intensity. The concentrations of several ethyl ester compounds in wine responsible for the fruity aroma, including ethyl hexanoate, ethyl octanoate, and ethyl butanoate, were significantly higher in scions grafted to Schwarzmann, 3309C, Merbein 5489, and C29, compared to scions grafted to 101-14 Mgt, 1103 Paulsen, and ungrafted vines. This suggests that rootstock plays an important role in altering the texture and flavour of Pinot noir wine. Conclusions. Grafting Pinot noir to any rootstock in this study caused changes in the phenolic and volatile content