Australian Journal of Grape and Wine Research

Genetic erosion of grapevine is becoming a serious worldwide problem and preserving its germplasm is an urgent task. Chile is not an exception to this scenario, where diverse factors led by the replacement of traditional varieties by renown cultivars have reduced the vineyard diversity. Therefore, discovering and characterizing minor varieties were the main objectives of this study. In addition to the official catalogue of around 100 grapevine varieties used to produce wine, we present here 89 genotypes not previously described as present in Chile, widely dispersed in the main wine valleys, which were retrieved from vineyards, small collections, and city gardens. Strikingly, we found 49 grapevines with allele patterns not described before. Ten of these may be old European varieties; the other 39 have allele patterns similar to Criolla varieties (e.g., descendants from the crossing of European varieties born in America). A parentage analysis performed with 15 SSR markers in these 39 N.N. samples revealed that most of them are descendants of the so-called foundational varieties Listán Prieto and Muscat of Alexandria, plus others in lower proportion such as Mollar Cano and Muscat à petit grains blancs, as well as known Criollas varieties such as Italiona and Moscatel Rosado. The 89 genotypes not described in Chile structured in three distinguishable groups: Criolla varieties, Central European varieties, and a third group enriched in Iberic varieties. The prevalence of each Criolla accession was quite variable, some corresponding to a single or a few vines found at a single place, while others were spread in several vineyards, even in different valleys, suggesting they were positively selected and propagated at some time. All the new Criolla varieties were different than the recently described Criollas found in Argentina. The discovery, rescue, and documentation of this rich heritage of Vitis vinifera L. genotypes found in Chile is the first step of a long-term work that should be continued with the evaluation of their enological characteristics, yield, and optimal management systems, aiming for the diversification of the local wine industry.

Background and Aims. Salt exclusion is an important attribute for wine grapes since many countries have limits to the concentration of sodium (Na⁺) and/or chloride (Cl⁻) tolerated in wine. The aim was to investigate whole plant capacity for Na⁺ and Cl‾ exclusion and the within-plant partitioning of accumulated ions to better understand these important salt tolerance traits. Methods and Results. Rooted cuttings of 140 Ruggeri and K51-40 (good and poor shoot Cl⁻ excluders, respectively) and five hybrids from a cross between the two genotypes were used. When challenged with salinity, 140 Ruggeri limited the accumulation of Cl⁻ and Na⁺ in the stem, petioles, and laminae and had a significantly lower whole plant concentration of Cl⁻ and Na⁺ when compared to K51-40. The latter indicates that 140 Ruggeri accumulates less Cl⁻ and Na⁺ than K51-40 by a lower uptake or a potentially greater efflux by roots, or both. While K51-40 accumulated significantly more Na⁺, it was able to retrieve it from the xylem; store it in the roots, stem, and petiole; and keep the lamina concentration comparable to that of 140 Ruggeri. Petioles of all genotypes appeared to play a role in limiting Cl⁻ accumulation in laminae and particularly for K51-40, to limit Na⁺ accumulation in laminae. Conclusions. The grapevine capacity for Cl⁻ and Na⁺ exclusion can be defined primarily as the lower net accumulation on a whole plant basis, reflecting the difference between the uptake and any efflux that may occur. Lower root to shoot transport is a key factor in shoot Cl⁻ and Na⁺ exclusion. Petiole accumulation assists in limiting the Cl⁻ and Na⁺ accumulation in the laminae. Significance of the Study. The study addressed the knowledge gap by examining Cl⁻ and Na⁺ exclusion on a whole plant basis, highlighting a range of within-plant mechanisms that act in limiting the accumulation of both ions in the laminae.

While winegrowers usually want to achieve consistent yield targets, there is a high degree of yield and price (and hence gross revenue) variability in winegrape production. The aim of this study was to determine whether there are differences in yield and revenue variability across climates, varieties, and regions in Australia. This was performed by estimating statistical models of the impact of these three variables on the coefficient of variation of yield and gross revenue per hectare. The results suggest that hotter and drier regions exhibit lower interannual yield variability, something that in the past may have been largely explained by the use of irrigation, but which may change in the future with climate change and higher water prices. The results also showed that there are sometimes differences in yield and revenue variability, not only across regions, but also between varieties.

Many varietal aromas of wine are located in the berry skin. In the present study, we evaluated four important Austrian grape varieties: Grüner Veltliner, Sauvignon Blanc, Traminer, and Pinot Blanc. We assessed whether prefermentation skin contact, fermentation with the skin (only for Grüner Veltliner), and stabulation (lees stirring; only for Sauvignon Blanc, Traminer, and Pinot Blanc) could enhance the varietal aromas of the different grape cultivars. The aim was to intensify the varietal aromas without extracting the undesirable phenols. We performed a detailed analytical characterisation of approximately 100 volatile and phenolic compounds as well as a sensory characterisation. Although mash fermentation significantly increased the spicy aromas of Grüner Veltliner, which are affected by climate change (especially the sesquiterpene rotundone), it markedly decreased the fruitiness and increased the bitterness; therefore, it cannot be recommended for this cultivar. For Sauvignon Blanc, stabulation is a possible option; the varietal aromas (thiols and methoxypyrazines) were increased in the final wines of these variants. For Pinot Blanc and Traminer, prefermentation skin contact yielded the best results: for Traminer, it produced the highest content of monoterpenes (especially z-rose oxide), and for Pinot Blanc, it produced the highest content of ethyl esters. To summarise, stabulation will not completely replace classic skin contact, and mash fermentation is certainly not an alternative for the production of standard Grüner Veltliner wine. However, additional investigations are necessary with regard to other grape varieties, terroirs, and vintages before we can make final recommendations.

Rootstocks are used in viticulture to manage plant pests and diseases, particularly phylloxera and root-knot nematodes, and to improve grape and wine production. A wide range of rootstocks are commercially available, making selecting the optimal rootstock a difficult decision. In particular, distinct rootstock genotypes may manifest varying degrees of tolerance or resistance to abiotic stress, necessitating meticulous consideration during the rootstock selection process. This article reviews characteristics of various commercial rootstocks, as well as rootstocks being developed in recent years. This review further discusses responses of rootstocks to drought, soil nutrients, and soil pH. This review mainly focuses on influence of rootstocks on physiology characteristics of grafted scions rather than berry yield and quality. The breadth of this review benefits both researchers and practitioners by providing comprehensive summery of rootstocks to inform selection and to guide future research.

The term minerality is often used to describe high-quality still white wines produced in cooler regions, such as Chablis. What minerality means in sensory terms and what is responsible for its presence is the subject of debate, however. This study explored the concept of minerality by analysing 16,542 Chablis Premier Cru tasting notes entered into CellarTracker between 2003 and 2022 on wines three to seven years old, together with weather, topography, and soil data for the Chablis area. The top three words used to describe Chablis Premier Cru wine were citrus, minerality, and acidity. Mentions of minerality declined between 1999 and 2019 vintages, whereas those of acidity, salinity, floral, orchard fruit, and stone fruit increased. The trends for minerality and salinity were slightly stronger with the year of tasting (2005 to 2022) than vintage. Bigram analysis indicated that consumers were more than 1.5 times as likely to refer to a stony kind of minerality as a saline one and only rarely smoky minerality. Use of the term minerality was correlated with growing season temperature and sunshine hours (negatively with each), as well as vineyard aspect (negatively with percentage vineyard area facing South or South-West), but not with Kimmeridgian soil type. The results imply that soils and geology are not a principal source of minerality in Chablis wine, but growing season warmth and sunshine are relevant to minerality. There is no simple explanation of minerality in Chablis wine; however, the recent decline in the use of this term for Chablis wine may be a consequence of three factors in combination: (i) it has become less fashionable; (ii) consumers are choosing “saline” instead of “mineral” when appropriate, but retaining it for “stony” sensations; and/or (iii) warming from climate change has reduced minerality.