Australian Journal of Grape and Wine Research最新文献

Background and Aims: Under a surge of interest in the dual use of land, very scant information is still available about physiological and agronomical adaptations of the grapevine grown under agrivoltaics (AV) panels and their compatibility with light energy capture.

Methods and Results: A setup of permanently horizontal AV panels mounted from veraison until harvest over Cabernet Sauvignon (CS) and Malvasia di Candia aromatica (MC) row sections was compared with an open-field (OF) row section of the same cultivars. Uninterrupted diurnal and seasonal whole-canopy gas exchange measurements were taken from August 9 to September 29. In contrast, total light interception, leaf gas exchange and water status, cluster temperature, and photochemical quantum yield of photosystem II (φPSII) readings were concentrated on August 13–14. Vegetative growth, yield components, ripening dynamics, grape and wine composition, and volatile and bound aromas were performed. Based on diurnal and seasonal direct and diffuse light measurements, panels cut incoming light by about 47%. In contrast, the reduction of the whole-canopy net carbon exchange rate (NCER) and transpiration (T) was only 7%–9%. Canopy water use efficiency (WUE) was not significantly affected, although, in CS, WUE lowered when panels cast maximum shade over the central part of the day. With yield components not being affected, under AV, harvest was delayed by 17 and 12 days versus OF in CS and MC, respectively. However, while technological maturity was comparable in MC under OF and AV, the latter had lower monoterpenes and fermentative esters, which might hint at less floral and fruity notes. The rainy late season compromised grape maturity on the CS–AV vines, and the final wines were lighter in color and body.

Conclusions: Under the specific panel’s configuration, the whole-canopy gas exchange was minimally affected in front of a 47% light depletion. Panels caused a consistent ripening delay that was detrimental to free-volatile wine components in MC. In contrast, it worsened grape and wine quality in CS primarily due to unfavorable late-season weather.

Background and Aims: Musts with a high concentration of gluconic acid can be obtained because of the colonization of grapes by spoilage fungi and bacteria or the treatment of musts with glucose oxidase. Our research aims to obtain yeast strains capable of degrading this gluconic acid.

Methods and Results: Assays were conducted by inoculating selected strains of Schizosaccharomyces pombe in both must and wine. The most effective strategy to achieve the highest gluconic acid consumption was the inoculation of S. pombe strains into the must. Fermentations of Verdejo grape must, supplemented with sodium gluconate, were conducted using strains of S. pombe in both unique and sequential inoculations with a strain of Saccharomyces cerevisiae at 24 and 48 h. A metabolic and kinetic variability were observed in the consumption of glucose, fructose, malic acid, and gluconic acid among the strains under investigation that exhibited a high fermentation power and capacity to degrade up to 100% of malic acid.

Conclusions: The S. pombe strains, Sp3 and Sp7, consumed the highest amount of gluconic acid, 90.5 ± 3.7% and 63.9 ± 3.6%, respectively. Sequential inoculations at 24 h significantly reduced gluconic acid consumptions. In contrast, sequential inoculations at 48 h demonstrated no differences with the unique Strains Sp1, Sp3, and Sp4.

Background and Aims: Grapevine berry ripening is driven by water and sugar loading from the phloem, beginning with berry softening and ending at physiological maturity. This study aimed to characterise the kinetics of sugar and water accumulation at the berry population level under different climatic, vigour and crop management conditions.

Methods and Results: The experiments were conducted in a commercial vineyard of the ‘Tannat’ cultivar in Uruguay, for 8 years. Two zones with high (H) and low (L) vigour were delimited. In two contrasted rainy and dry years, specific treatments (nitrogen, water availability and leaf/fruit ratio) were carried out. The sugar and water accumulation kinetics were studied on populations of berries, which were both synchronised from the onset of ripening to maximum sugar loading and normalised by their maximum volume. A bilinear model between berry growth and sugar accumulation was fitted, indicating an apparent uncoupling between water and sugar loading. Wet and high-vigour conditions accentuated this apparent uncoupling compared to dry and low-vigour conditions, with maximum berry growth reached earlier than the maximum sugar content. In addition, management practices favouring plant water and carbon status positively influenced the duration of ripening (up or down).

Conclusions and Significance: This study provides a deeper understanding of how management practices can be harnessed to improve grape production. Water management was a key lever to counteract the climatic and/or vigour impact both on the apparent uncoupling between berry growth and sugar loading at the population level and the asynchrony of berry development within the population.

Background and Aims: The grape and wine sector in Australia and around the world is under increasing pressure from climate change, disease threats and sustainability concerns, necessitating the development of fast and innovative solutions that can also preserve the sought-after quality traits of elite cultivars.

Methods and Results: A simplified and cost-effective method for DNA-free protoplast gene editing and plant regeneration was assessed for its broad applicability using the two most common red and white winegrape cultivars commercially grown in Australia. Plant regeneration and editing efficiencies were investigated with downy mildew disease and associated susceptibility genes, VviDMR6-1 and VviDMR6-2, as the trait and gene-editing targets. High rates of edited plant regenerants displaying normal growth and development were recorded for all four cultivars within 4–5 months, and flow cytometry assays were employed to assess the ploidy status of regenerants and filter out nondiploid plants. Fungal assays with glasshouse-grown, edited Chardonnay plants suggested a previously unreported role for VviDMR6-2 and jasmonic acid in grapevine susceptibility to downy mildew.

Conclusions: This study has demonstrated that a relatively simple and robust protoplast isolation, DNA-free protoplast transfection and plant regeneration workflow can be used to efficiently produce nontransgenic, diploid, edited clones with desired phenotypes of four elite winegrape cultivars, including the highly recalcitrant Cabernet Sauvignon.

Background and Aims: The longicorn beetle Xylotrechus arvicola (Olivier) (Coleoptera: Cerambycidae) is an important pest in vineyards of the Iberian Peninsula. Previous studies have reported that different varieties of grapevines Vitis vinifera exhibit varying susceptibility to infestation by this species.

Methods and Results: Adult X. arvicola captured were monitored using interception traps (CROSSTRAP) in vineyard plots cultivated with five different grapevine varieties (‘Tempranillo’, ‘Prieto Picudo’, ‘Mencia’, ‘Albarin’ and ‘Verdejo’) in the southern region of León province from 2017 to 2020. Tempranillo and Prieto Picudo had the highest number of X. arvicola captures, consistent with being the most susceptible varieties reported to be attacked by X. arvicola larvae. Verdejo had the lowest number of captures. In all varieties, the greatest period of adult emergence and subsequent captures occurred in June. However, in warmer springs, this emergence period started earlier, in May. The number of X. arvicola captured over time was significantly different between sexes, as well as in the interaction between captures and days across all varieties and years studied.

Conclusions: Our results provide valuable information for the integrated control and management of this pest. Placing traps in vineyards on the described dates and regularly monitoring them will help determine peak flight periods (i.e., the highest number of insects captured). This will allow for timely application of phytosanitary treatments, targeting the greatest number of insects. Further trials should be conducted in other vineyards with these types of traps and attractants to corroborate the results obtained.

Viticulture is facing important challenges in cultivation and management since grapevines are particularly vulnerable to changes in environmental conditions. Heat waves, extreme temperatures, and unpredictable weather patterns have become more frequent in wine-growing regions, creating an uncertain future for growers. In response, shading nets have emerged as a promising and adaptable technology to mitigate the adverse effects of climate change on grape production and wine quality. By moderating the vine microclimate, shading nets reduce solar radiation, decrease the extreme heat and wind speed, and improve water-use efficiency, enhancing ripening dynamics and preserving berry quality. However, the effectiveness of shading nets varies depending on the shade provided and the specific characteristics of the nets, highlighting the importance of adjusting the strategies to the specific needs of each environment, productive system, and grape variety. This review explores the influence of shading nets on grapevine physiological responses, including their ability to enhance resilience to stress. It examines their impact on grape and wine quality, providing insights into this vital adaptive tool for the future of viticulture.

In response to growing consumer expectations for greater diversity and novel flavour profiles in wines, this study explored the use of alternative wood species in oenology. The effects of six alternative wood species – sweet chestnut, common hazel, Robinia, blackcurrant, vineyard peach, and grapevine – on Austrian Vitis vinifera L. cv. Grüner Veltliner wine were examined after a 98-day contact period using both toasted and untoasted wood chips. The aim was to characterise the similarities of these alternative wood species to traditionally used oak. A comprehensive analytical profiling was conducted, quantifying over 50 wood-associated compounds, including hydroxycinnamic and benzoic acids, ellagitannins, lactones, carbonyl compounds and volatile phenols. Currently, only oak and sweet chestnut are approved by the International Organisation of Vine and Wine for oenological applications, with wood chips permitted exclusively from the genus Quercus. Based on the results, toasted sweet chestnut was the most promising alternative species for use as wood chips. It enhanced the wine colour intensity more effectively than oak, while its phenolic composition, particularly catechin levels and hydroxycinnamic acids, aligned moderately with oak. Furthermore, wine treated with toasted sweet chestnut presented comparable concentrations of vescalagin and castalagin. The similar levels of carbonyl compounds, such as furfural, further underlined its suitability. Although volatile phenol levels, including vanillin, exceeded those of oak, wine treated with toasted sweet chestnut remained comparable in its overall composition. Based on these findings, toasted sweet chestnut is recommended for approval as wood chips, although additional sensory and toxicological studies are necessary to substantiate this recommendation.