Cabernet Sauvignon Vineyard Research Articles

Long-term effects of different irrigation strategies on yield components, vine vigour, and grape composition in cv. Cabernet-Sauvignon (Vitis vinifera L.)

There are still some traditional vine-growing areas in Spain in which water-stressed vines are considered to produce berries with the highest quality must. To assess vine response to water availability, measured in terms of crop yield, vegetative development, and grape composition, five different irrigation treatments were evaluated over a five-year period in a Cabernet-Sauvignon vineyard in the Madrid region (Spain): no-irrigation (T0), water provided at 20 % of the reference evapotranspiration (ETo) (T20), water provided at 45 % of the ETo (T45), water provided at 20 % of the ETo until veraison and at 45 % thereafter (T20-45), and water provided at 45 % until veraison and 20 % thereafter (T45-20). A yield increment was observed with increasing water volumes. The T45 vines returned a consistent yield of around 8 t/ha, and a mean shoot weight of 30–50 g. The T0 and T20 plants showed reduced yields and vegetative growth in most years (yields being the most acutely affected). Berry weight was the yield component most influenced by water availability. In years of low rainfall, fertility was markedly reduced in the T0 vines. Providing a smaller irrigation volume before or after veraison (the T20-45 and T45-20 treatments) led to reductions in berry weight, cluster weight, and shoot weight over the last 3 years of the trial. Berry composition was almost unaffected by irrigation strategy. Taking into account yield, water use efficiency, and berry composition, the T45-20 treatment was the most efficient irrigation strategy.

Selective harvesting is a feasible and profitable strategy even when grape and wine production is geared towards large fermentation volumes

Background and Aims: Previous work has identified the potential for enhancing the profitability of both grapegrowing and winemaking through the implementation of selective harvesting. However, there has been a perception that such strategies may not be feasible when winery infrastructure is geared to large production volumes, such as is commonly the case in Australia's warm irrigated regions. This work sought to examine the merits of this perception. Methods and Results: The tools of Precision Viticulture were used to identify zones of similar vineyard performance in two Cabernet Sauvignon vineyards in the Murray Valley region of Victoria such that sufficient quantities of fruit were available for commercial scale vinification into different product lines. Wines from these zones were also made in small lots. Sensory analysis demonstrated that wines derived from like zones were indeed similar, whilst those from contrasting zones were discernibly different. A partial gross margin analysis strongly suggested that selective harvesting should be highly profitable. Conclusions: If market opportunity warrants it, selective harvesting of fruit into different product streams is a feasible and profitable strategy even when production is geared to large volumes. Significance of the Study: The work demonstrates that selective harvesting can be profitably applied in situations where production is geared to large fermentation volumes. It therefore provides a counter to the view that Precision Viticulture offers opportunities only to small (boutique) producers or to large, well-resourced companies with a flexible winery infrastructure.

Variation in vine vigour, grape yield and vineyard soils and topography as indicators of variation in the chemical composition of grapes, wine and wine sensory attributes

Background and Aims: Vineyard variability makes satisfaction of winemaker demands for uniform parcels of fruit that are suitable for particular product streams difficult. Indeed, it may not be possible to satisfy these demands without being able to adequately characterise differences between wines derived from different fruit parcels or different areas of the same vineyard, understanding how final wines are affected by management decisions implemented in the vineyard, and/or understanding the effects of variation in the vineyard's biophysical characteristics (e.g. soil, topography) on grape and wine composition. This work sought to identify and examine relationships between the chemical and sensory attributes of wines derived from different parts of the same block and the biophysical characteristics of these different vineyard areas. Methods and Results: Remote sensing of vine vigour, yield mapping and EM38 soil survey were used to identify zones of contrasting vineyard performance in a Cabernet Sauvignon vineyard in the Murray Valley region. Small-lot wines were made from fruit sourced from these zones. Both sensory and chemical analysis (solid phase microextraction-gas chromatography-mass spectrometry) of these wines demonstrated them to be different. Likewise, soil properties and indices of vine nutrition differed between the zones. Conclusions: This work suggests that it is possible for robust relationships to be established between specific (manageable) biophysical attributes of the place where grapes are grown and the sensory and chemical characteristics of the wines derived from them. It also supports the view that terroir is spatially variable at the within-vineyard scale. Significance of the Study: The work provides a foundation for further research aimed at establishing how specific sensory and/or chemical properties in wines might be modified through targeted management interventions in the vineyard.

Effects of Soil and Climatic Conditions on Grape Ripening and Wine Quality of Cabernet Sauvignon

The effects of climatic conditions and soil type on grape ripening and wine quality were studied for the period 2003–2005, in two Cabernet Sauvignon vineyards under the same climate but on very distinct soils. Climate effect was estimated by studying annual variations. Climatic conditions and soil had overall a significant effect on grape ripening. The effects of soil and climate could be explained mainly by their influence on plant water availability status. Soil type appeared to be determining wine phenolic composition, and related wine tasting characteristics.

Within-season temporal variation in correlations between vineyard canopy and winegrape composition and yield

Remote optical imaging can rapidly acquire information describing spatial variability in vineyard block performance. Canopy characteristics were derived from very high spatial resolution (0.25 m) optical imagery of a Cabernet Sauvignon vineyard acquired at various canopy growth stages. Within-season changes to correlation coefficients between vineyard canopy and ultimate composition and yield of harvested fruit were then investigated. Canopy area and density were observed to have significant relationships with yield and fruit quality indicators including berry size, anthocyanins and total phenolic content, but less significant relationships with total soluble solids. The strength and type of correlation varied with canopy growth stage. For anthocyanins and total phenolic content, correlations varied from non-significant before flowering to negative after flowering. For berry weight and yield, correlations varied from negative before flowering to positive after flowering. For total soluble solids, there were some significant relationships but no clear temporal pattern. The results confirm that remote sensing is a useful tool to determine spatial variability in fruit composition and yield. However, both the timing of image acquisition and the way in which canopy is quantified are important determinants of the direction and strength of correlations with fruit composition and yield.

A Vineyard Agroecosystem: Disturbance and Precipitation Affect Soil Respiration under Mediterranean Conditions

We investigated impacts of agricultural management practices on soil respiration (Rs) in a Cabernet Sauvignon (Vitis vinifera) vineyard (Oakville, CA; November 2003–December 2005). We determined (i) response of Rs to cover cropping, mowing and tillage; (ii) environmental factors controlling Rs; and (iii) total annual C lost through Rs A winter cover crop was either mown (CC+mow), or mown and tilled (CC+Till), and resident vegetation was tilled (RV+Till). Precipitation amount and pattern differed between years, and low Rs rates occurred during summer drought and high rates during wet periods. Total CO2 emissions differed only in Year 2 (RV+Till: 10.99 ± 0.30, CC+Till: 10.11 ± 0.49, CC+mow: 8.57 ± 0.54 Mg CO2–C ha−1). After tillage or mowing, Rs increased five‐ to six‐fold in tilled treatments and two‐fold in the mown treatment (Year 1). In Year 2, Rs increased two‐ to three‐fold after tillage only. Rs increased after ‘post‐management’ rainfall in spring and was 1.5‐ to 2‐fold greater in tilled than mown treatments in both years due to prior incorporation of plant biomass during tillage. After fall rainfall, Rs was 1.7‐fold greater in mown than tilled treatments (Year 1). Our findings suggest that the interaction of management practice with climate and soil conditions before disturbance (i.e., management and rainfall) influenced Rs Polynomial regressions of Rs on GWC and soil temperature indicated that Rs increased until gravimetric water content (GWC) reached 14 to 15% in tilled treatments and 20% in the mown treatment, subsequently declining, indicating thresholds of GWC at which soil temperature more strongly influences Rs

Using remote sensing to predict grape phenolics and colour at harvest in a Cabernet Sauvignon vineyard: Timing observations against vine phenology and optimising image resolution

Optical remote sensing can provide a synoptic view of grapevine photosynthetically-active biomass over entire vineyards both rapidly and cost-effectively. Such output offers viticulturists and winemakers a management tool of enormous potential with red grape varieties, especially if canopy architecture (defined in this way) can be linked to production of phenolics and colour in ripe grapes. Accordingly, this paper describes such associations for a Cabernet Sauvignon vineyard in Australia's cool-climate Coonawarra region. A link is established between physical descriptors of grapevine canopies (derived from remotely-sensed images), and subsequent measurements of grape phenolics and colour. High-resolution images were acquired on three occasions during each of two consecutive growing seasons and post-processed to a range of on-ground resolutions. The strength of correlation between those images and berry properties (both total phenolics, and colour levels at harvest), varied according to spatial resolution and vine phenology at the time of imaging. An image resolution corresponding approximately to row spacing resulted in the strongest correlations between berry constituents and image-based data on all occasions. Referenced to grapevine phenology, correlations were initially weak (insignificant) at bud-burst, reached maximum strength at veraison, then diminished somewhat as grapes ripened. Prospects for applying such remotely-sensed imagery (at an appropriate resolution and timing), to predict berry phenolics and colour at harvest, are discussed.

Flutuação populacional de Argyrotaenia sphaleropa (MEYRICK, 1909) (Lep: Tortricidae) com emprego de feromônio sexual sintético na cultura da videira

A lagarta-das-fruteiras, Argyrotaenia sphaleropa (Meyrick, 1909) (Lepidoptera: Tortricidae), é uma espécie freqüentemente encontrada danificando a cultura da videira e outras frutíferas de clima temperado na região Sul do Brasil e no Uruguai. Estudou-se a flutuação populacional de A. sphaleropa na cultura da videira com emprego do feromônio sexual sintético. Com base na avaliação semanal de machos de A. sphaleropa capturados em armadilha Delta contendo o feromônio sexual sintético (Z11,13-14Ac + Z11,13-14Al + Z11-14Al na proporção 4:4:1, impregnada em liberadores de borracha na dose de 1.000µg/septo), durante a safra 2003-2004, foram observados quatro picos populacionais na cultura da videira cultivar Cabernet Sauvignon. O primeiro pico populacional ocorreu no início do mês de outubro, o segundo no início de fevereiro, o terceiro teve o acme em meados do mês de março e o quarto no mês de junho. A temperatura média diária e a precipitação pluviométrica não exerceram influência sobre a captura dos insetos nas armadilhas. As informações deste trabalho permitem direcionar as táticas de controle para os períodos em que a população do inseto é mais elevada nos parreirais.

Outbreaks of Cladosporium Rot Associated with Delayed Harvest Wine Grapes in Chile.

Severe outbreaks of Cladosporium rot have occurred on berries in clusters of late harvest wine grapes (Vitis vinifera L.) during the 2003 to 2006 growing seasons. This disease was especially prevalent on Cabernet Sauvignon (CS) vineyards in central Chile where disease incidence commonly comprised 50 to 100% of the clusters at harvest. Symptoms appeared on mature grapes (total soluble solids [TSS] >22%) and were characterized by berry dehydration, a firm decay affecting a small portion of the berry and a superficial olive-green mold. Isolations made on acidified potato dextrose agar (APDA) consistently yielded olive-green colonies after 7 days at 20°C. On the basis of colony morphology and morphological characteristics of conidiophores and conidia, Cladosporium herbarum (Pers.:Fr) Link and C. cladosporioides (Fres.) de Vries were identified (1). These species were primarily separated by the presence of rough and smooth conidial surfaces, respectively. Koch's postulates were completed by inoculating 80 wounded mature (20% TSS) CS berries and incubating them at 10, 20, and 30°C. An equal number of wounded but noninoculated berries were left as controls. Berries were surface sterilized (75% ethanol for 30 s and 0.5% sodium hypochlorite for 60 s), inoculated with 10 μl of a 106 conidial suspension per ml applied to the wounds made with a sterile hypodermic needle. Dark, necrotic lesions, 1 to 6 mm in diameter, and a dark mycelial colony appeared on the surface after 7 days in chambers with relative humidity of >95%. Disease incidence was significantly (P < 0.05) influenced by temperature, with 90, 100, and 49% of inoculated berries becoming infected when incubated at 10, 20, or 30°C, respectively. C. herbarum and C. cladosporioides appeared to be equally pathogenic, producing symptoms similar to naturally infected CS berries, and were reisolated (100%) on APDA. These same isolates were pathogenic when tested on mature (TSS >16%) Thompson Seedless (TS) berries. Fungicide sensitivity tests were performed on detached TS berries challenged by placing 10 μl of a 106 conidial suspension per ml of C. herbarum on injured berries. Boscalid (0.5 mg/ml, Cantus WG; BASF, Santiago, Chile), iprodione (0.5 mg/ml, Rovral WP; Bayer Crop Science, Santiago, Chile), pyraclostrobin (0.085 mg/ml, Comet SC; BASF), and pyraclostrobin (0.009 mg/ml) mixed with boscalid at 0.017 mg/ml (Bellis WG; BASF) provided a significant control (P < 0.05) with efficacy between 84.3 and 95.9%. Azoxystrobin (0.188 mg/ml, Quadris SC; Syngenta Crop Protection, Santiago, Chile), kresoxim methyl (0.067 mg/ml, Stroby SC; BASF), and trifloxystrobin (0.06 mg/ml, Flint WG; Bayer Crop Science) provided partial control with efficacy between 23.1 and 42.1%. Cladosporium spp. have been previously reported (2). However, severe outbreaks of Cladosporium rot occur when berries become partially senescent because of a considerable delay in harvest (3). This appears to favor the development of these pathogens.

Studies on Colletotrichum acutatum and Greeneria uvicola: Two fungi associated with bunch rot of grapes in sub-tropical Australia

Vineyards in the Hunter Valley and Hastings Valley (sub-tropical NSW) were examined by unaided eye for visible symptoms of bunch rot diseases at berry maturity in 2003 (for a total of five varieties over seven vineyards). Grey mould (Botrytis cinerea) was evident in three vineyards, and ripe rot (Colletotrichum acutatum) was evident in four of those seven vineyards surveyed. Other bunch rots at six of the vineyards could not be readily identified by visual inspection. The incidence of fungi on grapevine reproductive structures (and potentially bunch-rot fungi) was then recorded for a Cabernet Sauvignon vineyard in the Hastings Valley during the 2004/5 and 2005/6 growing seasons, and outcomes are reported here in some detail. By berry maturity, C. acutatum and Greeneria uvicola (bitter rot) were the predominant pathogens isolated from those structures, and constitute the first such report of bitter rot fungi on wine grapes in Australia. Indeed, the frequency of latent infection by C. acutatum and G. uvicola increased with berry development during the growing season. Other fungi isolated included Alternaria spp., Botryosphaeria spp., Cladosporium spp., Epicoccum sp., Fusarium spp., Nigrospora spp., Pestalotia spp., Phomopsis viticola and Trichoderma spp. Isolation of B. cinerea from this vineyard was rare. Infection of various wine grape varieties in vitro with C. acutatum and G. uvicola at post veraison revealed all varieties to be susceptible over a range of temperatures (20—35oC). Based on laboratory studies, there was no infection of berries at a relative humidity (RH) < 50%, and infection diminished at 87% RH. Infection did occur if the berries were first incubated at 100% RH for 24 hours, and then transferred to an environment of lower humidity.

Latent heat flux over Cabernet Sauvignon vineyard using the Shuttleworth and Wallace model

The Shuttleworth and Wallace model (SW) was evaluated to estimate latent heat flux above a drip-irrigated Cabernet Sauvignon vineyard, located in the Pencahue Valley, Region del Maule, Chile (35°22′ LS; 71°47′ LW; 150 m above sea level). The performance of the WS model (LEws) was evaluated against the eddy-covariance method (LEed) on a 30 min time interval. Results indicate that the root mean square error (RMSE) and mean absolute error (MAE) were 29 W m−2 and 22 W m−2, respectively. For the vine evapotranspiration (ETv), RMSE was 0.42 mm day−1 and MAE was 0.36 mm day−1. The largest disagreements between LEed and LEws were observed under dry atmospheric conditions. Also, the sensitivity analysis indicates that predicted ETv by the SW model was sensitive to errors of ±30% in leaf area index and mean stomatal resistance, but it was not affected by errors in the estimation of aerodynamic resistances.

Response of Fruit Growth and Ripening to Crop Level in Dry-Farmed Cabernet Sauvignon on Four Rootstocks

An estimate of the amount of clusters that a vine can reasonably bring to maturity is essential for optimizing crop level. This work was conducted to determine whether the timing of maturity in a high-yielding, dry-farmed <i>Vitis vinifera</i> L. Cabernet Sauvignon vineyard could be manipulated through rootstocks and crop level. Cabernet Sauvignon, grafted on 5C Teleki (<i>V. berlandieri</i> Planch. <i>x V. riparia</i> Michx), 1103 Paulsen, 140 Ruggeri, and 110 Richter (<i>V. berlandieri</i> Planch. <i>x V. rupestris</i> Scheele), was used in a trial carried out in 1997 and 1998 in an 8-year-old vineyard near Oakville, California. Four levels of crop were imposed by winter pruning all vines to four-bud spurs and cluster thinning at veraison: treatment 1 (100%), or double crop, no thinned vines with ~26 shoots and 40 clusters per vine; treatment 2 (75%), in which 25% of clusters were thinned; treatment 3 (50%), the standard crop level in the study area or control, in which 50% of clusters were thinned and one cluster per shoot was retained; and treatment 4 (25%), in which 75% of clusters were thinned and one cluster every two shoots was retained. The time required to reach 23.5, 24.0, and 25.0 Brix was linearly dependent on crop level with a rate of about one day per each ton of grapes. Rootstocks and crop levels had no or little impact on fruitfulness, cluster and berry size, and final Brix. The reduction in sugar accumulation seems to be a sensitive measure for crop level and does not appear to be influenced by rootstock or environmental conditions.

Environmental effects on cv Cabernet Sauvignon (Vitis vinifera L.) grown in Hawke's Bay, New Zealand.: 1. Phenology and characterisation of viticultural environments

Six Cabernet Sauvignon vineyard sites in Hawke's Bay (New Zealand), selected out of 28 sites observed in 1996/97, were studied over three consecutive seasons in order to characterise viticultural environments of this region for this cultivar. Indices of precocity of vine phenology were used to analyse the relationship between phenology at the selected sites and vegetative growth, productivity, fruit ripening and wine sensory characteristics. Marked differences in indices of precocity existed between sites. These differences were mostly correlated with vine vegetative growth and canopy indices. There was no relationship between yield and vine phenology. Indices of precocity were correlated with certain juice constituents measured on a common date, as well as the sensory scores of wines produced by microvinification from grapes harvested on different dates and maturity levels. Vineyard sites that differed in indices of precocity also differed in their environmental characteristics, particularly in soil physical properties and water balance.

Relationship of ammonium ion and abscisic acid in bunchstem tissue to the incidence of the disorder bunchstem necrosis in grapevine

Bunchstem tissue from three Cabernet Sauvignon vineyards during three years were analysed for ammonium ion and abscisic acid to test whether their levels correlated with the incidence of the disorder bunchstem necrosis (BSN, Stiellahme). Levels of free ammonium ion, known to be toxic to plant tissue when excessive, were found to be low, considerably lower than those reported in the literature. Neither free nor released ammonium ion levels correlated with BSN incidence. Similarly the levels of abscisic acid, a stress hormone that can induce BSN symptoms when applied to bunches, showed no correlation with BSN incidence.

Changes in Elemental Sulfur Residues on Pinot noir and Cabernet Sauvignon Grape Berries During the Growing Season

Elemental sulfur residue on grape berries was determined for a Pinot noir vineyard in the Carneros region and a Cabernet Sauvignon vineyard in the Oakville area of Napa County, California. Each vineyard was divided into four quadrants. Each quadrant received two or three wettable sulfur applications prior to bloom, followed by scheduled applications of either elemental sulfur dust, triadimefon (Bayleton), fenarimol (Rubigan), or myclobutanil (Rally) according to label instructions. Residual elemental sulfur levels were determined at two-week intervals (5 sample dates) from the day after final sulfur dusting until harvest using an inductively coupled plasma spectrophotometer (ICP). Immediately after the final dusting, residual sulfur levels were 7.9 and 13.6 µg/g berry weight and decreased rapidly to 3.0 and 2.3 µg/g berry weight for the remainder of the season for Cabernet Sauvignon and Pinot noir, respectively. Residues for grape berries which were not dusted were significantly less (<i>p</i> = 0.05, Duncan9s multiple range test) and ranged from 2.5 to 0.2 and 3.1 to 0.5 µg/g berry weight for Cabernet Sauvignon and Pinot noir, respectively, for most sample dates. In comparison, 16 other vineyard blocks with differing final sulfur dust applications were sampled at harvest. Residual sulfur levels ranged from 0.9 to 2.7 µg/g berry weight.

EFFECTS OF EVAPORATIVE COOLING ON GRAPE BUD HEAT SUMMATION AND ONTOGENY

The major production risk for grapes on the Texas High Plains is freeze injury to buds and wood due to deacclimation brought about by warm periods in late winter. Delaying plant development by any means would reduce risk from injury. Reducing cumulative heat summation between rest and bloom has resulted in delayed bloom on peaches but internal rest is not expressed in grapes. An evaporative cooling system using microsprinklers was applied to a Cabernet Sauvignon vineyard during Jan.-April 1989. The system provided a 25 second wetting period at 3 minute intervals anytime air temperatures exceeded 10° C. Bud temperatures were monitored continuously with a data logger and correlated to cumulative budbreak and plant development. Significant bud cooling was achieved and by normal budbreak cooled buds lagged uncooled buds by 72% in degree days. A similar lag in budbreak was recorded early with some cooled buds breaking 3 weeks after most uncooled buds were open. Cooled plants continued to lag uncooled plants at bloom and even at harvest where oBrix and pH were lower and total acids higher from cooled plots.

Effect of Drip Irrigation Schedules on Growth, Yield, Must Composition and Wine Quality of Cabernet Sauvignon

Four drip irrigation schedules were studied in a Cabernet Sauvignon vineyard located at Luzit in the Adulam region of Israel. Seasonal water application in the range of 220 to 320 mm did not have a considerable effect on wine quality, whereas 400 mm caused a significant quality reduction. Irrigation cut back during the last six weeks before harvest advanced ripening, but this was not necessarily always connected with improved quality. Irrigation had a greater effect on growth than on crop level and therefore altered the crop load expressed as yield to pruning weight ratio. The yield to pruning weight ratio varied between 4 and 10 and was positively related to wine quality and color, and tartaric to malic acid ratio of the must. Negative relationships were found between wine quality and several parameters such as pruning weight, berry weight, leaf, must and wine K content, total and malic acid content, and wine pH. The involvement of specific and non-specific irrigation effects on wine quality is discussed.

Effect of Irrigation and Crop Level on Growth, Yield and Wine Quality of Cabernet Sauvignon

Four drip irrigation schedules were applied to a Cabernet Sauvignon vineyard during five seasons. The vines of each irrigation schedule were subjected to three cluster thinning treatments resulting in three different crop levels. Water uptake from soil reserves was increased by restricted irrigation, intensive vegetative growth, and low crop load. Restricted irrigation also increased water uptake from soil reserves located at the periphery of the wetted soil zone. Total water uptake was the highest in the most intensive irrigation schedule (A), and the total water uptake from the soil decreased as a function of depth and distance from the tricklers in all treatments. Vines with low crop load extracted more water in the continuous irrigation schedule, whereas the vines with high crop load extracted more water in schedules with irrigation cutback before harvest. The interaction between increased irrigation quantity and frequency with either extremely high or low crop load resulted in delayed sugar accumulation. Delayed ripening was associated with low wine quality only in the most intensive irrigation schedule (A) with the low crop load treatment tending to give the lowest wine quality. The reduced wine quality in the intensive irrigation treatment was expressed by low tasting scores and wine color and by high pH. Wine K was negatively correlated with crop load in all irrigation schedules though no clear relation of K to quality was apparent.

Effect of Crop Level and Crop Load on Growth, Yield, Must and Wine Composition, and Quality of Cabernet Sauvignon

Three crop load treatments by cluster thinning immediately after bloom were applied to a Cabernet Sauvignon vineyard located at Luzit in the Adulam region of Israel during five consecutive years. The crop load values expressed as the grape yield to pruning weight ratio varied between 4 in the severely thinned treatment and 10 in the unthinned treatment. Wine quality as determined by tasting was significantly higher in the unthinned as compared to the severely thinned treatment in two out of the five experimental years. The five year averages of the wine quality score did not vary significantly. The pruning weight was negatively rank correlated with crop level and crop load, and positively with the harvest delay. Potassium leaf, must and wine content was negatively rank correlated with crop load, crop level, must malic acid and wine color, ash and tartaric acid content. Comparison of these results with those obtained earlier with Carignane lead the authors to suggest that crop load values above 10 have a negative effect on wine quality whereas no significant effect is apparent with values lower than 10.