Australian Journal of Grape and Wine Research

This study aimed to examine the various Swiss wine consumer segments, evaluate whether and how these segments had changed during the past decade, and formulate recommendations for targeted marketing. Data were collected through an online survey involving randomly selected Swiss households who were invited using flyers; the final sample size was N = 512. With the use of a shortened version of the questionnaire devised for a similar study published in 2011, we were able to compare the results of the said study with the present results. The results of the principal component analyses revealed eight factors. The factor scores were then used in hierarchical cluster analyses, which in turn revealed seven distinct segments of wine consumers. Four of these had already been identified 10 years ago: involved (21.9%), price-conscious (20.3%), lowbrow (16.0%), and image-oriented (5.3%) consumers. Three new segments emerged: local (15.2%), traditional (11.9%), and relaxation-seeking (9.4%) consumers. Our results show that each wine seller has its own place in the market and can benefit from the present study, which determines the appropriate marketing mix for a specific segment.

Leafroll and red blotch are two of the most consequential viral diseases threatening the sustainability of the wine grape industry. To promote uptake of management practices, there is a critical need to understand the motivating factors for decision makers and optimize the dissemination and acquisition of knowledge. From 2019 to 2020, we conducted semi-structured interviews with 42 wine grape industry professionals (“decision makers”) in the Western United States, from California (n = 32) and Washington (n = 10). The interview questions explored the perceptions and experiences of these decision makers as they learned about disease ecology, interacted with their immediate and extended community, and adopted management practices. Utilizing qualitative thematic analysis, we identified nine economic, knowledge, and social-behavioural factors along with 24 sub-factors. These factors illustrated the interplay between knowledge, communication, economics, labour, government subsidies, regulatory practices, and collaborative efforts that influence adoption. The quality of knowledge dissemination emerged as a critical aspect. Using the interview data along with a quantitative survey (n = 145), we also explored how growers use 14 educational resources to learn about grapevine viruses. Using these findings, extension educators can optimize their activities to disseminate knowledge on grapevine viral disease management. In total, this study provides context for the agricultural industry, research scientists, extension educators, and other supporting partners of the financial, interpersonal, and technical issues that must be overcome to successfully manage grapevine viral diseases.

Wine producers perform early wine quality prediction based on berry morphology, the taste of the berry and the measurement of basic chemical parameters. Incorporating analysis on grape and wine volatiles could potentially achieve a more accurate prediction of wine quality, but forming these models requires careful selection of grapes, controlled fermentations, and standardised quality assessment. Here, we present 3 models for the prediction of quality in Shiraz wine. Modelling was performed by general regression analysis with 4-fold cross-validation: Model 1 (R² = 99.97% and 4-foldR² = 97.61%) for prediction of wine quality from wine volatiles, Model 2 (R² = 99.89% and 4-foldR² = 98.42%) for early prediction of wine quality from free-bound and glycosidically bound grape volatiles, and Model 3 (R² = 91.62% and 4-foldR² = 80.21%) for the prediction of wine quality from free grape volatiles only. The accuracy of these models presents an advancement in the early prediction of wine quality and provides a valuable tool to assist grape growers and winemakers to support the understanding of quality in the vineyard to better direct scarce resources.

Background and Aims. Shiraz (Syrah) is a dark-skinned cultivar of the wine grape Vitis vinifera that forms the basis of some of the world’s most iconic wines. Worldwide, Shiraz is the fourth most planted grapevine cultivar; however, it represents the most planted cultivar in Australia. Given the importance of Shiraz to worldwide wine production, this study aimed to produce a reference genome for this cultivar while investigating the unique genetic variants and ancestral origins of this iconic variety. Methods and Results. Long-read ONT data were selected to produce a highly contiguous genome assembly for Shiraz. Phylogenetic reconstruction using high-quality genome assemblies for wine grape cultivars provided further support of a kinship between Shiraz and Pinot Noir. Harnessing long-read data, transposable element insertions potentially affecting gene function were characterized in Shiraz and assessed relative to other cultivars. This revealed a heterogenous landscape of transposon insertion points across cultivars and uncovered a specific combination of allelic variants at the VviTPS24 terpene synthase locus. Conclusions. This establishment of a Shiraz genome provides a detailed view of the genetics that underpin this cultivar, including the discovery of a specific combination of VviTPS24 variants, which when combined with appropriate environmental triggers may allow Shiraz to produce high levels of rotundone, the aroma compound responsible for the distinctive peppery characteristics of this cultivar. Significance of the Study. The availability of a reference genome for Shiraz expands the pool of genomes available for wine grapes while providing a foundation resource for whole-genome studies involving this iconic cultivar, including intracultivar variant identification and transcriptomic studies using a matching reference genome.

Background and Aims. Grape phylloxera in Australia comprises diverse genetic strains that feed on roots and leaves of Vitis spp. The G38 phylloxera strain was detected on roots of Vitis spp., for the first time in North East Victoria in 2015. Prior to 2015, G38 phylloxera was only known to feed on leaves. The aim of this study was to evaluate the survival and development of G38 phylloxera on roots of diverse Vitis spp. under field, controlled laboratory, and greenhouse conditions. Methods and Results. In the field, emergence traps quantified first instars and alates emerging from roots of diverse rootstocks and Vitis vinifera L. High numbers of phylloxera were collected in traps placed at vines of rootstocks 101-14, 3309 Courderc and Schwarzmann. Nodosity were also observed on roots of 101-14, 3309 Courderc and Schwarzmann in the field and in-pot vines experiments. The better performance of G38 phylloxera on these three rootstocks compared to V. vinifera in the field and in potted vines parallelled the excised roots experiments. Conclusions. The relatively high performance of G38 phylloxera on the 101-14, 3309 Courderc and Schwarzmann rootstocks suggest a susceptible response and could be associated with rootstock parentage. Further investigation is warranted to determine implications for rootstocks development. Significance of the Study. These findings are fundamental for decision-making in phylloxera risk assessment and rootstock selection. The study reaffirms the need for triphasic (in vitro, in planta, and in-field) rootstock screening protocols for phylloxera.

Background and Aims. Shiraz disease (SD) is a viral disease associated with Grapevine virus A that causes significant yield loss in economically important grape cultivars in Australia such as Shiraz and Merlot. Current diagnostic methods are time-consuming and costly. This study evaluates an alternative methodology using visible remote sensing imagery to detect SD in Shiraz grapevines. Methods and Results. High-resolution visible remote sensing images were captured of Shiraz grapevines in two South Australian viticultural regions over two seasons. The projected leaf area (PLA) of individual grapevines was estimated from the images. Virus-infected vines had significantly lower PLA than healthy vines in the early season but fewer difference after veraison. The lower PLA was only observed in grapevines coinfected with grapevine leafroll-associated viruses (GLRaVs) and Grapevine virus A (GVA). Shiraz vines infected with either GLRaVs or GVA had similar PLA to healthy vines. Conclusions. High-resolution RGB remote sensing technology has the potential to rapidly estimate SD infection in Shiraz grapevines. Our observations of shoot devigouration only in coinfected vines calls into question the etiology of SD. Further validation of the PLA technique incorporating different regions, seasons, cultivars, and combinations of viruses is needed for improving the robustness of the method. Significance of the Study. This preliminary study presents a new rapid and low-cost surveillance method to estimate SD infections in Shiraz vineyards, which could significantly lower the cost for growers who conduct on-ground SD visual assessments or lab-based tissue testing at the vineyard scale.