Australian Journal of Grape and Wine Research最新文献

Background and Aims. Grapevine is susceptible to several diseases and requires a large use of fungicides. Sustainable alternatives must be safe for humans and the environment and also should not interfere with must fermentation. The aim of this study was to implement the use of a rare sugar, tagatose, against powdery mildew and downy mildew and to assess possible side effects on Saccharomyces cerevisiae fermentation. Methods and Results. Tagatose was evaluated for the suppression of powdery mildew and downy mildew under controlled and field conditions and for its impact on S. cerevisiae fermentation of synthetic and grape musts. Tagatose applied at 8 kg/hareduced powdery mildew and downy mildew severity and incidence on grapevine leaves and bunches under field conditions. Tagatose caused a limited and transient slowdown of the fermentation with no negative impact on yeast viability and wine chemical composition at the end of the fermentation. Conclusions. Tagatose is a promising alternative for sustainable grapevine protection against powdery mildew and downy mildew with no negative impacts on the must fermentation. Significance of the Study. These findings pave the way for grapevine protection strategies based on the use of rare sugars as sustainable fungicides in integration with other plant protection products.

Background and Aims. Vitis vinifera L. is a major global horticulture crop which holds historical connections contributing to the development of human culture. The main objective of the study was to explore the genetic diversity and structure of grapes curated at the germplasm bank of Aragón and link them to cultivar utilization, putative geographic origin, and historical events. Methods and Results. The genetic diversity of the 411 accessions of the Grapevine Germplasm Bank was assessed using 26 SSR markers. SSR markers VVIP31, VMC4F3-1, VVIV67, and VVS2 distinguished the 156 nonredundant genotypes found in the collection. The profiles were compared to the El Encin database, and 105 were identified as known cultivars, of which 93 were Spanish, 12 were from other European origins, and 51 others were not known. The 51 profiles, as they were all collected in Spain, were designated as Spanish unknown for further analysis. To establish a comparative study for principal coordinate analysis (PCoA) and structure, we kept 113 identified genotypes from this collection but added 61 representative genotypes with diverse European and oriental origins. Bayesian analysis and PCoA showed four distinct groups of grape cultivars: (1) traditional Spanish wine grape from Aragón or cultivated along the Ebro River, (2) Spanish wine grape, (3) Spanish and oriental table grape, and (4) Italian, Portuguese, French, and German-Slovenian wine grape varieties. Conclusions. The 51 unknown Spanish genotypes were not registered yet in any European commercial list and are of special interest. These genotypes could be ancient cultivars adapted to local climatic and environmental conditions and probably resilient to face the new conditions derived from climate change.

Background and Aims. The cultivation of grapevines in England is expected to benefit under climate change. Yet assessments of future wine climates remain undeveloped. Accordingly, this study assesses how climate change might modify frost risk for Chardonnay in the Southeast England viticulture region. Methods and Results. Cold-bias-corrected climate projections from the UKCP18 Regional (12 km) perturbed parameter ensemble (PPE) climate model under RCP8.5 are applied with phenological models to determine how frost risk and the timing of key grapevine phenophases might alter under climate change. Notwithstanding the uncertainties associated with projections of key viticulture-related bioclimate variables, the last spring frost was found to advance at a greater rate than budburst, indicating a general decrease in frost risk. Conclusions. Although projections point to an improving climate for viticulture across Southeast England, frost will remain a risk for viticulture, albeit at a reduced level compared to the present. Furthermore, the strong cold-bias found for temperature simulations used in this study needs to be given careful consideration when using the UKCP18 projections for viticulture impact assessments of climate change. Significance of the Study. This study highlights the present sensitivity of viticulture to climate variability and the inherent uncertainty associated with making future projections of wine climate under climate change.

Background and Aims. Cofermentation and blending are traditional winemaking practices. This study reports their comparative chemical and sensory outcomes. Methods and Results. Malbec and Merlot were made into monovarietal wines, cofermented (COF), blended postalcoholic (PAF), and postmalolactic fermentation (PMLF), at a 50/50 proportion. Wines were followed up to 3 years of bottle aging. Tannins were 50% higher in monovarietal Merlot wines, which improved production of large polymeric pigments in Merlot-based cofermented and blended wines. Addition of Malbec favored production of small polymeric pigments. After 3 years of bottle aging, polymeric pigments were higher in cofermented and blended wines. PMLF blended wines showed 15% improved copigmentation and 25% increase in wine colour. The perception of wine length was positively correlated with red fruit aroma (R² = 0.94 and p = 0.006) and negatively correlated with earthy aroma (R² = 0.91 and p = 0.012). Conclusions. Blending postalcoholic fermentation highlighted more of the individual character of each monovarietal wine in the final blend. Cofermentation and postmalolactic fermentation blending tended to equalize the sensory profile of the resulting wines but also showed higher complexity of aromas than monovarietal wines. Significance of the Study. Cofermentation and blending are both suitable winemaking practices for increasing the polymeric pigment content and the sensory complexity of the resulting wines.

Background and Aims. No-till is considered a core practice of conservation and climate-smart agriculture. Nevertheless, recent evidence suggests that the benefits of this practice for climate change mitigation might be overestimated, particularly in the short term. Methods and Results. In a three-year field experiment, we investigated the environmental and agronomic performance of this practice by looking at changes in soil physical properties, C and N pools, as well as vine yield and grape quality. No-till increased stratification in the distribution of active soil C (POXC), further accentuating the already existing difference between top and subsoil. No-till also slightly reduced the daily efflux of CO₂ from the soil during the rainy season, showing that these plots were less prone to lose C than tilled plots. Nonetheless, no-till did not increase total soil C stocks. This, together with the lack of differences in cumulative N₂O emissions, resulted in similar global warming potential in till and no-till plots. Vine yield and grape quality remained unchanged in the no-till compared to the tilled plots. Conclusions. Even though no-till did not result in short-term climate change mitigation, results of this study suggest changes in the ecological processes leading to C accumulation and mineralization and that may result in future C sequestration. There were no deleterious effects of no-till on grape yield and quality. Significance of the Study. This study shows that reducing tillage intensity in vineyards is a feasible strategy from an agronomic standpoint.

Background and Aims. Smoke exposure occurred in the Adelaide Hills region in December 2019 due to a wildfire, when wine grapes were peppercorn-size green berries. Previously, pre-veraison smoke exposure had been identified through model experiments as unlikely to affect grape composition, whereas smoke exposure after veraison can have a major effect on wine flavour. Hence the effects of pre-veraison smoke on grape and wine composition, and smoky sensory properties of wine were investigated. Methods and Results. Chardonnay, Pinot Noir and Shiraz were investigated and eight blocks with varied smoke exposure were selected for each cultivar. Berries were sampled initially four weeks after the fire and at harvest, and mature grapes were made into unoaked wines. Established smoke exposure markers, phenolic glycosides, were found in berries at pre-veraison and at harvest from the high smoke exposure sites, with concentrations well above those found in non-smoke exposed fruit. Volatile phenols were also elevated in grapes at harvest. The resulting red wines from some exposure vineyards were high in volatile phenols, glycosides and smoky flavours. However, most of the Chardonnay wines expressed much less smoky flavours, despite similar levels of smoke exposure of grapes. Conclusions. Pre-veraison smoke exposure can result in elevated concentrations of volatile phenols and their glycosidic metabolites in grape berries and wine and cause strong smoky flavour in wine. Significance. The wine sector and land management agencies responsible for controlled burns need to consider the effect of smoke from fires near vineyards even very early in the growing season.

Background and Aims. If bioprotection has already been proven to limit the development of spoilage flora on musts, its effectiveness against oxidation depends on the winemaking process. To optimize its application, this study analyzed the evolution of the chemical composition of the bioprotected musts and wines, according to different settling routes. Their impacts on the organoleptic characteristics of wines were also studied. Methods and Results. A bioprotected must was subjected to 6 different maceration routes before AF (triplicates), varying the duration and temperature parameters. A temperature value ≤12°C was the main factor independently of the duration which allowed a good implantation of the bioprotectant. An increase of the maceration duration at 12°C led to browning of the must, without significant effect on the final color of the wine, which was felt as more “floral,” with more length in the mouth. Conclusions. The bioprotectant implantation and its effectiveness on the sensory profile of the wine was guaranteed at maceration temperature values lower than 12°C. Significance of the Study. This study participates in the improvement of the bioprotection management in white winemaking, with the guarantee of a positive impact of the prefermentation maceration without sulphites on the organoleptic profile of the wines.

Background and Aims. This research investigates spatial and temporal trends in budburst timing across Australian wine regions from 1910–2019. The potential drivers of these observed trends were then identified, including anthropogenic climate change and large-scale climate drivers (El Nino–Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), and Southern Annular Mode (SAM)). Methods and Results. The timing of budburst was approximated using accumulation measurements applied to Australia wide gridded temperature data. We show that the modelled budburst date has been gradually shifting to earlier in the year for most (95%) Australian wine regions, at an average rate of one day every 24 years. This linear trend in budburst timing is likely to be associated with steadily increasing air temperatures due to anthropogenic climate change. Significant interannual variability was also observed and was correlated with IOD and SAM; however, no significant relationship was found with ENSO. Positive IOD phases result in budburst occurring on average four days earlier than the long-term average; however, this can be as high as eight days. Conclusions. The results of this study highlight that budburst timing for wine grapes is not a stationary phenomenon and is influenced by both natural and anthropogenic conditions. Significance of the Study. Understanding variability and trends in modelled budburst timing will assist tactical and strategic management practices and improve phenological modelling and adaptation planning for climate change.

Background and Aims. In viticulture, one of the effects of warming trends is the advance of budburst date and the consequent increased risk of spring frost-related damage. In 2021, severe frost events affected a large fraction of European viticulture. In a cv. Barbera vineyard, located in NW Italy, primary bud shoots (PBS), secondary bud shoots (SBS), and suckers (SK) were tagged after the occurrence of freezing temperatures in spring. The goal of the study was to clarify if SBS could partially restore yield loss and analyze their contribution to fruit composition. Methods and Results. The number of developing SBS and SK correlated with the number of killed PBS. While PBS bore 1.44 inflorescences per shoot, SBS had much lower fertility (0.4), with SK at intermediate levels (0.85). The vine yield was 40% of the previous season, with SBS bunches contributing just 17% of the total. SBS produced smaller and looser bunches, as compared with PBS (−28% mass and −27% compactness). At harvest, no difference was found in grape total soluble solids (TSS) among different shoot types. However, the TSS average was notably higher than that observed in the previous season (27.8°Brix vs. 23.3°Brix in 2020). Interestingly, while in PBS and SK, a direct correlation (linear and quadratic, respectively) existed between the leaf area to yield ratio (LA/Y) and grape TSS or total anthocyanins, this did not occur for SBS. Conclusions. In the case of spring frost damage, the number of PBS avoiding fatal injuries will drive agronomic results at harvest since SBS contribution to total yield is modest due to low shoot fruitfulness. The frost-induced increase in vine LA/Y leads to a dramatic rise in grape TSS and phenolics. Significance of the Study. When spring frosts kill a significant number of primary shoots, an altered grape composition at harvest should be expected due to changes in vine balance. Therefore, the vineyard management should be adjusted accordingly early in the season. Further studies are needed to test specific post-frost canopy management strategies ensuring yield, optimal fruit composition, and cane renewal.

Background and Aims. The composition of grapes (Vitis vinifera L.) at harvest is a key factor that determines the future quality of wine. The work aimed to evaluate and compare the environmental impact of the most evaluated technological parameters using three approaches: the wet-chem method, the optical method using benchtop devices, and the optical method using a prototype smart and cost-effective device (Technology Readiness Level: 5). Methods and Results. The life cycle assessment (LCA) methodology was used to identify the most environmentally sustainable solution in a “from-cradle-to-grave” approach. The functional unit was identified by the execution of the analyses necessary to measure the three technological parameters: TSS, pH, and TA. The findings show that the optical analysis carried out with the prototype is the most suitable and green solution (i.e., with the lowest environmental impact in all the impact categories analysed); in fact, the same technology has proved to be 3.2 times more sustainable than the wet-chem method for the best average environmental performance. Conclusions. The research demonstrated the environmental impact advantages of the optical analyses for assessment of grape composition. Significance of the Study. Innovations in agriculture and the development of smart solutions represent advantages for managing and monitoring the composition of agri-food products that are a green solution for the industry.