Municipal and winery wastewater can provide a valuable irrigation source in regions where water accessibility is problematic or sustainable disposal of waste is essential. It is imperative, however, that when used for irrigation, water conservation benefits are not compromised by a decline in soil and plant health. To date, published literature investigating the use of wastewaters for grapevine production is restricted to a limited set of studies. Globally, wastewater usage within the horticultural sector, including winegrape production, is increasing. It is necessary, therefore, to better understand the short- and long-term implications of such practice. Although wastewaters may contain a range of organic and inorganic pollutants, this review focuses primarily on specific issues associated with high salt loading that is typical under wastewater irrigation. Managing salt, in particular sodium (Na⁺) and potassium (K⁺), in wastewater will be necessary in order to maintain the soil physical, chemical and biological health in the long term. Soil structural degradation resulting from a high concentration of exchangeable monovalent cations is of major concern where wastewater is being used for irrigation. This review will address (i) the effect of wastewater irrigation on vine performance and grape quality; (ii) chemical and physical changes in soils irrigated with municipal and winery wastewater; and (iii) management practices that may assist in ameliorating vineyard soils abundant in monovalent cations as a result of wastewater irrigation.

Background and Aims:  In the Vitaceae, stilbenoid viniferins constitute a relatively restricted group of molecules based on a trans-resveratrol structure and represent the main known phytoalexins. The aim of this work was the development of a new method for the chromatographic separation and accurate quantification of viniferins found in grapevine leaves following infection with Plasmopara viticola.

Methods and Results:  An interspecific F1 population was used, deriving from the cross between Merzling and Teroldego, respectively, partially resistant and susceptible to P. viticola. Analysis was carried on a liquid chromatography-mass spectrometry (LC-MS) system, using a reverse phase column. A method was validated for detailed metabolite profiling, with accurate identification and quantification of trans-resveratrol, trans-piceid, trans-pterostilbene, a condensation product between (+)-catechin and caffeic acid, and the whole class of stilbenoid viniferins in P. viticola-infected grapevine leaves, using their respective standards. Synthesis was ongoing, and 6 days after infection, it was possible to see the highest concentration of stilbenoids for all genotypes. On the other hand, the intensity of stilbene induction did not show a clear and homogeneous correlation with the position of the leaves in the young shoot.

Conclusions:  The method described in this paper provides the basis for performing in a single run a targeted analysis of resveratrol, piceid, pterostilbene and the whole class of stilbenoids in P. viticola-infected grapevine genotypes.

Significance of the Study:  To our knowledge, this is the first paper that has reported on detailed metabolite profiling with accurate identification and quantification of the main viniferins in grape leaves following infection with P. viticola, using the respective standards.

Background and Aims:  Central Chile represents a large area of viticultural potential for high-quality wine production. Although climate has been commonly accepted as one of the main drivers of Chilean viticultural success, its main features have not been described from a viticultural perspective. Our work focused on analysing the spatial climatic structure in this area with respect to the potential for grapevine production.

Methods and Results:  Climatic indices were used to estimate heat accumulation during the growing season, thermal regime during ripening and the potential water balance at the end of the growth cycle. These indices were calculated for 54 weather stations and clustered using hierarchical classification. The spatial variability in climatic potential was well explained by differences in heat accumulation and by March thermal amplitude.

Conclusions:  General patterns showed that the ripening of grapes was associated with low night-time temperatures. Proximity to the sea had a strong influence, and there was a dominant north–south orientation of the climatic groups.

Significance of the Study:  This study described the differences and relative importance of major climatic factors in Central Chile, providing an increase in knowledge about the climate of Chilean wine-producing regions.

Background and Aims:  Heat shock protein 90 (Hsp90) proteins constitute an important gene family of molecular chaperons. High-temperature stress, which is often combined with drought stress, may exert major constraints to grapevine growth and development. The aim of this study was to characterise the Vitis vinifera Hsp90 gene family.

Methods and Results:  Using the complete grapevine genome sequences, four cytoplasmic and three organelle-specific V. vinifera Hsp90 (VvHsp90) proteins were identified. Phylogenetic analysis revealed that they share high sequence similarity with their Arabidopsis counterparts, while the cytosolic isoforms are clustered into two distinct groups (VvHsp90.1 and VvHsp90.2). Transcriptional analysis showed that a representative gene from the first group (VvHsp90.1a), in contrast to VvHsp90.2a, is induced by heat shock in all vegetative tissues/organs tested. Interestingly, it was also expressed in tendrils in the absence of stress. The severity and duration of heat stress influenced in a complex manner the expression profile of VvHsp90.1a, while the other VvHsp90s tested were rather constitutively regulated. However, the endoplasmic reticulum-specific VvHsp90.7 was mildly and transiently induced by a relatively prolonged heat stress. Combined drought with heat stress resulted in a delay in VvHsp90.1a induction.

Conclusions:  Gene structure organisation and expression characteristics of VvHsp90s resemble those of their Arabidopsis orthologs, although species-specific differences also exist. Differential regulation of genes suggests functional diversification among isoforms.

Significance of the Study:  This is the first report on the characterisation of Hsp90s in grapevine. The present study contributes to a deeper understanding of the complex molecular responses of grapevine to stress.

Background and Aims:  Microbiological stability of bottled wine is largely dependent on the bottling process as the last technological operation. In this survey, yeast contamination was monitored and characterised during wine bottling.

Methods and Results:  Samples of wine, apparatus surfaces and bottles were collected. Yeast counts were recorded and colony morphotypes were differentiated. Isolates were characterised by restriction enzyme digests of polymerase chain reaction amplified regions of 26S ribosomal DNA. For unknown patterns, DNA sequencing was performed. The presence of Zygosaccharomyces bailii and Torulaspora delbrueckii in the filling tubes was also confirmed in the final product. Another important point of contamination was the corker jaws.

Conclusions:  A great diversity of yeast species was found, indicating that these habitats are prone to microbial development.

Significance of the Study:  Evaluation of the level and diversity of yeast contamination during wine bottling allowed to alert producers for the need to evaluate and control microbial contamination.

Background and Aims:  Grape phylloxera, Daktulosphaira vitifoliae (Fitch), is a significant insect pest of grapevines and can cause mild to severe economic damage to ungrafted European grapevine, Vitis vinifera L., depending on the insect clonal type. Dry heat treatment is currently recommended as a disinfestation method to restrict the spread of phylloxera to uninfested vineyards on viticultural machinery.

Methods and Results:  G1 and G4 first instar grape phylloxera clones were subjected to two relative humidity (30 and 100%) and four temperature (30, 35, 40 and 45°C) treatment combinations to find the optimal temperature–humidity combination to achieve 100% phylloxera mortality over the shortest time period.

Conclusions:  One hundred per cent mortality of two phylloxera clonal strains was achieved at 45°C for 75 min at 30% relative humidity. Some differences in clonal susceptibility to temperature and humidity treatments were observed.

Significance of the Study:  A novel screening method was developed, which validated the nationally recognised dry heat disinfestation protocol for grape phylloxera. The study also highlighted that different clonal lineages of phylloxera are influenced by both temperature and humidity.

Background and Aim:  To predict harvest time for logistic applications in vineyards and wineries, measurements of total soluble solids (TSS) are typically combined with projections assuming TSS increases at 1°Bé/week. Here, three questions were asked: (i) what is the magnitude and direction of the bias in estimates of ripening assuming 1°Bé/week across varieties, regions and seasons? (ii) what are the climatic drivers of this bias? and (iii) could thermal rates improve predictions?

Methods and Results:  Actual TSS of Chardonnay, Shiraz and Cabernet Sauvignon was measured in commercial vineyards in Coonawarra, Barossa Valley and Riverland. Predictions used (i) the default 1°Bé/week; (ii) variety- and location-specific chronological rates between 0.8 and 1.2°Bé/week; and (iii) variety- and location-specific thermal rates between 0.009 and 0.019°Bé/Cd. In eight of the nine cases, 1°Bé/week biased ripening predictions. Seasonal bias correlated with evaporative demand in the Riverland and Coonawarra and with minimum temperature in the Barossa Valley. Thermal rates were not superior to calibrated chronological rates to predict ripening.

Conclusion:  Locally calibrated rates significantly improved ripening predictions for major grapevine varieties in regions with contrasting climates and viticultural profiles.

Significance of the Study:  Improved prediction of ripeness time would allow for better allocation of key resources in vineyards and wineries – labour, time, machinery, transport, analytical services, chemicals and storage.

Background and Aims:  Total leaf area and its distribution inside the canopy are known to influence the photosynthesis capacity as well as grape quality and health. The aim of this work was to evaluate the effectiveness of a simple and innovative training system characterised by an open canopy called ‘SAYM’ (a closing Y-shaped training system derived from the spur-pruned single cordon and trained to an inclined shoot-positioned trellis type) as well as the possibility of using traditional machines during harvesting and pruning after closing the structure just before grape harvesting.

Methods and Results:  The SAYM was applied on eight rows of 80 vines from an experimental Sangiovese vineyard and compared to vertically shoot-positioned (VSP) trellis type during the 2004–2008 seasons. In comparison to VSP vines, the SAYM was able to reduce the incidence of botrytis rot and improve grape and wine quality (alcohol, anthocyanins, phenolics, tannins and colour intensity), while maintaining an adequate yield (about 13 t/ha) without significantly increasing the management operations of the vineyard.

Conclusions:  The SAYM was able to bring together economically and easily the advantages guaranteed by training systems characterised by horizontally divided canopy with the limitation of production costs by the use of traditional mechanical harvesters and pruners.

Significance of the Study:  SAYM can be proposed as a functional training system able to improve grape and wine quality, which is easy and inexpensive to manage.

Background and Aims:  The impact of Esca, a cryptogamic disease affecting woody tissues of grapevines (trunk, branches and shoots), was investigated on phenolic and sensory qualities of Cabernet Sauvignon grapes, derived musts and wines.

Methods and Results:  Global phenolic analyses revealed no major difference between healthy and affected grapes whereas high-performance liquid chromatography analyses showed decreases in the skin concentrations of catechin and epicatechin and of anthocyanins for the two vintages assessed. Proanthocyanidin characteristics, and particularly mean degree of polymerisation, were strongly decreased in skin proanthocyanidin polymeric fractions. Chemical analyses of wines made with different percentages of fruit from Esca infected grapevines confirmed the moderate impact of Esca on phenolic composition. Nevertheless, sensory analyses revealed a loss of wine sensory quality perceptible with as little as 5% of affected fruit in wines.

Conclusions:  Phenolic variations in grapes and in derived wines may be related to changes to grapevine physiology caused by Esca fungi that impact on flavonoid metabolism. The chemical and sensory variations between wines can also be related to the delayed ripening delay of fruit from Esca infected grapevines.

Significance of the Study:  Esca moderately affected the phenolic composition of grapes and decreased the sensory quality of wines, suggesting a dramatic increase in the economic importance of Esca if no control methods are found.

Background and Aims:  Although cover crops are largely used in vineyards, limited information is available on the amount of water they use. The aim of this study was to quantify cover crop evapotranspiration (ET_cc) in the inter-row of a Concord (Vitis labruscana Bailey) vineyard. In addition, the hypothesis that ET_cc could be accurately estimated through a relationship with incident solar radiation and reference crop evapotranspiration was tested.

Methods and Results: ET_cc was measured using mini-lysimeters located across the inter-row of single curtain- and Geneva double curtain-trained vines. Over the course of the study, the ET_cc ranged between 0.6 and 2.6 mm/day. ET_cc was linearly correlated with a reference crop evapotranspiration adjusted for the solar radiation incident on the vineyard cover crop (r² = 0.81) in both single curtain and Geneva double curtain.

Conclusions:  Our results indicate that ET_cc under different vineyard canopies is mainly explained by the difference in solar radiation transmitted to the cover crop.

Significance of the Study:  This study provides new insights on the possibility to estimate ET_cc in a vineyard. A more complete energy balance study is needed to test our hypothesis under different environmental conditions.

Background and Aims:  The goal of this study was to investigate the relationships between NDVI values at different phenological stages and measurements of grape parameters at two different harvest dates.

Methods and Results:  The research was done on a Sangiovese vineyard in Central Italy. Over four seasons, airborne NDVI measurements acquired between June and August were related to grape parameters (yield per vine, pH, °Brix, anthocyanins and polyphenols) at technological harvest (H1) and two weeks later (H2). Correlations were higher at H1 and decreased at H2 with a different rate depending on the parameter. °Brix and pH correlations showed a moderate rate of variation between H1 and H2; bigger differences and a different inter-annual dynamic were observed in anthocyanins and polyphenols between H1 and H2.

Conclusions:  The ability of NDVI to discriminate different grape classes was confirmed, but its efficacy substantially varies depending on the harvest date. These results suggest the existence, within the same vineyard, of different grape populations having specific timing and shape of ripening curve; as a consequence, distinct vigour zones of the vineyard show a different evolution of the content of grape parameters between the two harvests thus influencing the degree of correlation between grape quality and NDVI measurements.

Significance of the Study:  This is the first study in which harvest date has been considered for its influence on the predictive skill of RS. It therefore highlights not only the importance of spatial variation within the single vineyard, but also the importance of ripening dynamics.

Background and Aims: Most white wines lose fresh and fruity characteristics, associated with volatile esters, during ageing in the bottle. A higher storage temperature accelerates these changes. The aim of this study was to examine the influence of storage temperature on the chemical and sensory properties of Sauvignon Blanc wines.

Methods and Results: Three commercially bottled Sauvignon Blanc wines from the 2008 and 2009 vintages were stored at 5, 10, 18°C and at room temperature for 12 months. Wines stored at warmer temperatures (18°C and room temperature) contained lower concentrations of acetate esters, including the prominent varietal thiol 3MHA, and ethyl esters of fatty acids, than the wines stored at cooler temperatures (5 and 10°C). A warmer temperature accelerated the rate of ester hydrolysis. Conversely, the concentrations of ethyl esters of branched acids were higher in wines stored at the warmer temperatures. The sensory profile of the wines was assessed after 12 months for the two 2008 wines and after 8 months for the 2009 wine. The wines stored at cooler temperatures were characterised by higher fruity and fresh vegetal aromas, whereas the wines stored at warmer temperatures exhibited the opposite sensory profile, with dominant woody/smoky/oaky, buttery, flinty and canned asparagus notes.

Conclusions: These results indicate that temperature-dependent hydrolysis processes are critical for Sauvignon Blanc aroma stability during the first year in the bottle.

Significance of the Study: Cool storage temperature conditions can significantly increase the shelf-life of Sauvignon Blanc wines by preserving their fruity and fresh green characters.

Aims: To determine the effects of applied water amounts at various fractions (0.2, 0.6, 1.0 and 1.4) of grapevine evapotranspiration on leaf gas exchange of Thompson Seedless grapevines.

Methods and Results: Midday stomatal conductance (g_s) decreased linearly as leaf water potential (Ψ_l) and soil water content decreased. Leaf net CO₂ assimilation rate only decreased once midday Ψ_l values were less than −1.0 MPa and when ∼50% of the soil water content at field capacity had been depleted. The mean seasonal midday A/g_s ratio (intrinsic water use efficiency) was greatest for the 0.2 irrigation treatment and decreased as applied water amounts increased. Diurnal A and g_s for vines irrigated at the 0.6 level or greater reached a maximum prior to midday remained constant thereafter before decreasing late in the afternoon, while those for vines that received less water decreased subsequent to the first measurement of the day.

Conclusions: A and g_s responded differently to vine and soil water statuses under the conditions of this study. There was no midday depression in either A or g_s for vines irrigated at full evapotranspiration.

Significance of the Study: The values of Ψ_l, A and g_s reported here would serve as criteria to indicate that vines were well watered.

Background and Aims: Water uptake through the stem surface contributes to total water uptake of submerged grape berries (Vitis vinifera L.). The objective was to identify the site of this uptake.

Methods and Results: Uptake of water and a fluorescent dye was studied using a single berry + stem system. To identify the site of water uptake, the cut end of the stem and selected regions of the stem surface were coated with a silicone sealant. Water uptake was determined gravimetrically. After immersing in dye solution, the stem and the receptacle region of the stem/berry junction fluoresced, but the exocarp did not. Fluorescence of vascular bundles in stem and berry indicated that the dye taken up was transported into the berry. Selective coating of the various stem parts revealed that at steady state (96 to 144 h), the stem/berry junction (0.11 ± 0.04 mg/h), receptacle (0.09 ± 0.03 mg/h) and the remaining stem surface (0.08 ± 0.03 mg/h) contributed approximately equally to total water uptake in the whole stem region (0.24 ± 0.05 mg/h), which in turn accounted for 55% of uptake of a berry + stem (0.43 ± 0.05 mg/h).

Conclusions: Stem/berry junction, and periderms of abscission zones and lenticels represent regions of preferential water uptake into detached grape berries.

Significance of the Study: Extrapolating from the single berry system to an intact bunch on a grapevine demonstrates that water uptake through the stem tissues inside a compact bunch may contribute to berry cracking under vineyard conditions.