Viticultural Practices Research Articles

Impact of aeroponic cultivation and plant growth regulators on the biochemical composition of grapevine leaves

Background: Grapevine (Vitis vinifera L.) is a globally important perennial fruit crop, renowned for its economic value and cultural significance. Grape leaves, while often underappreciated, play a vital role in culinary traditions and are valued for their cultural, nutritional, and health benefits. However, the availability of grape leaves is constrained by viticulture practices and chemical treatments that prioritize fruit production over leaf harvesting. This study seeks to compare the biochemical characteristics of grapevine leaves from the cultivar 'Deghin Yerevani' grown from virus-free, tissue-cultured plants under aeroponic and soil conditions within a greenhouse. Objective: To evaluate the impact of aeroponic versus soil-based cultivation and the application of specific growth regulators on the biochemical composition and nutrient content of 'Deghin Yerevani' grapevine leaves, with the goal of optimizing conditions for high-quality leaf production. Materials and Methods: This study, conducted from 2021 to 2023 at the Scientific Center of Agrobiotechnology, ANAU, utilized virus-free in vitro plants of Vitis vinifera L. cv. 'Deghin Yerevani', sourced from the National Grape Field Collection. Plants were cultured in four treatment groups with varying growth media compositions: PGR-free, with Indole-3-acetic acid (IAA), with IAA and Gibberellic acid (GA₃), and with IAA, GA₃, and 6-Benzylaminopurine (BAP). Post-culturing, plants were transferred to either an aeroponic system, which used a misting cycle and maintained controlled environmental conditions, or to a greenhouse with a defined soil mix and monitored moisture levels. Both systems operated for 8 weeks, with each treatment replicated three times. Chlorophylls a and b, ascorbic acid, sugars, and macro- and micronutrient contents were analyzed, and statistical significance was determined using standard error and Student’s t-test (p < 0.05). Results: Grapevine leaves from 'Deghin Yerevani' plants grown in aeroponic systems exhibited significantly higher chlorophyll a, chlorophyll b, and total chlorophyll compared to those grown in soil. Growth regulators, particularly IAA, GA3, and BAP, enhanced chlorophyll content, sugar levels, and Vitamin C across both cultivation methods. Aeroponic systems showed superior results with increased sugar content (5.7 g/100g) and Vitamin C (20.4 mg/100g) compared to soil-based cultivation. Nutrient analysis revealed higher levels of nitrogen, phosphorus, potassium, calcium, and magnesium in aeroponics. Overall, growth regulators and aeroponic cultivation improved the biochemical and nutrient profiles of grapevine leaves. Conclusion: The study demonstrated that aeroponic cultivation and the application of growth regulators significantly enhanced the biochemical composition of grapevine leaves. Higher levels of chlorophyll, sugar, and Vitamin C, along with improved nutrient content, were observed in aeroponic systems compared to soil-based cultivation. These findings underscore the benefits of aeroponics and growth regulators in optimizing grapevine leaf quality, suggesting potential for improved yield and nutritional value in grapevine production. Keywords: 'Deghin Yerevani', grapevine, in vitro propagation, functional foods, Aeroponic Cultivation, Plant Growth Regulators

Enhancing Red Table Grape Coloration Using Tsikoudia: A Novel and Sustainable Approach.

Achieving optimal coloration in red table grapes, especially in warm-climate regions, presents significant challenges due to high temperatures that inhibit anthocyanin biosynthesis. Conventional methods to enhance grape coloration, including the use of abscisic acid (ABA), ethephon, foliar nutrient supplementation, and viticultural practices like cluster trimming and girdling, have limitations related to cost, regulatory restrictions, and potential adverse effects on grapes quality. This study proposes the application of tsikoudia, a traditional Greek alcoholic beverage, as a novel, sustainable, and cost-effective alternative to conventional practices. Tsikoudia, applied during the veraison stage, significantly improved the coloration of 'Crimson Seedless' and 'Red Globe' grapes by enhancing anthocyanin accumulation and altering color parameters. Specifically, lightness (L*), chroma (C*), and hue angle (h), measured using the CIE-Lab color system, were reduced, while the Color Index for Red Grapes (CIRG) was increased. Additionally, total anthocyanin content, determined through spectrophotometric analysis, also showed an increase. These changes indicate a more intense red coloration. This research highlights the effectiveness of tsikoudia in improving grape coloration and contributes to the development of more sustainable viticultural practices.

From vineyard to glass: Measuring consumers’ willingness to pay for innovative rootstock-produced wine through an experimental auction

Availability of new rootstocks in vineyards offers improved sustainability and adaptability to changing climatic conditions. However, the adoption of these innovations in the wine industry can be hindered by consumer perceptions and uncertainty about the intrinsic and extrinsic characteristics of the new rootstock-produced wines. This study aims to address these concerns by examining consumer preferences towards M4 rootstock-produced wines through a consumer test and a willingness-to-pay assessment based on a Becker-DeGroot-Marschak auction analysis. A non-hypothetical experiment design, involving 201 wine consumers from the Veneto and Friuli Venezia Giulia regions of Italy, was employed to identify differences in new patterns of wine consumption due to the information provided. Results show that consumers do not identify noticeable taste differences between wines produced with innovative and traditional rootstocks. However, when informed about the water-saving benefits, their willingness to pay for wines made with the innovative rootstock is 5% higher than for wines using traditional rootstocks. This additional willingness to pay becomes statistically insignificant after tasting the wine. The introduction of the M4 rootstock among vine growers appears to be an effective solution in meeting consumer demand for high-quality products made with environmentally-friendly methods that conserve scarce resources, such as water. The findings of this study contribute to the ongoing debate on the development of sustainable and economically viable viticultural practices that address the challenges posed by climate change.

Foliar applications of phenylalanine and prohexadione calcium for managing tannin content in cold-hardy hybrid grape cultivars

Cold-hardy hybrid grape cultivars have low tannin content compared to Vitis vinifera cultivars, which leads to unbalanced red wines and therefore low-quality wines. Viticultural practices, such as nitrogen fertilisation and the use of plant growth regulators, have shown to be effective interventions to modify tannin content in V. vinifera cultivars and may be effective with cold-hardy hybrids. Foliar applications of phenylalanine (Phe, 100 mg/L) and prohexadione calcium (ProCa, 50 mg/L) were applied separately and in combination (ProCa+Phe) to Marquette grapevines grown in Iowa, USA in 2022 and 2023. Treatments were assigned following a split-plot design. Berry weight, diameter, seeds per berry, tannin content, and iron-reactive phenolics content of skins and seeds were analysed at five phenological time points. Samples from treated vines were compared to untreated control samples using a random-intercepts linear regression model. Overall, the effect of year was more impactful than the individual effects of treatments due to differences in temperature and rainfall during berry development. However, skin and seed tannin and IRP were significantly affected by the Year2023:ProCa interaction at 3 weeks post fruit set and véraison, respectively, suggesting ProCa treatment may be more effective with multiple applications in consecutive years. Low application rate may be a reason for limited treatment effectiveness and further work on dose response may demonstrate foliar sprays of Phe and ProCa to be effective tools at managing phenolics content in Marquette grapes.

Versatile method for grapevine row detection in challenging vineyard terrains using aerial imagery

Accurate detection and differentiation of grapevine canopies from other vegetation, along with individual grapevine row identification, pose significant challenges in precision viticulture (PV), especially within irregularly structured vineyards shaped by natural terrain slopes. This study employs aerial imagery captured by unmanned aerial vehicles (UAVs) and introduces an image processing methodology that relies on the orthorectified raster data obtained through UAVs. The proposed method adopts a data-driven approach that combines visible indices and elevation data to achieve precise grapevine row detection. Thoroughly tested across various vineyard configurations, including irregular and terraced landscapes, the findings underscore the method’s effectiveness in identifying grapevine rows of diverse shapes and configurations. This capability is crucial for accurate vineyard monitoring and management. Furthermore, the method enables clear differentiation between inter-row spaces and grapevine vegetation, representing a fundamental advancement for comprehensive vineyard analysis and PV planning. This study contributes to the field of PV by providing a reliable tool for grapevine row detection and vineyard feature classification. The proposed methodology is applicable to vineyards with varying layouts, offering a versatile solution for enhancing precision viticulture practices.

Aroma Potential of German Riesling Winegrapes during Late-Stage Ripening

The “aromatic maturity” of winegrapes is not fully understood, particularly during the later stages of ripening. The contribution of grapes to wine aroma has historically been challenging to determine, given most aroma compounds originate from nonvolatile precursors. In this study, an analytical approach previously developed for red winegrapes was adapted to assess the “aroma potential” of Riesling from two vineyards in Essenheim and Durbach, Germany, during the 2022 vintage, by extracting and hydrolyzing aroma precursors in an anoxic model wine matrix. Following sensory and chemical analyses of the hydrolysates using flash profiling and gas chromatography, a multiple factor analysis revealed vineyard- and ripening-dependent changes to aroma, even after total soluble solids had plateaued. As samples matured, green apple and fresh/vegetal aromas were prominent among the Durbach hydrolysates, likely due to persistent concentrations of hexanol. Hydrolysates from both vineyards nonetheless developed more pronounced citrus fruit, tropical fruit, and floral aromas, reflecting increased concentrations of various norisoprenoids and terpenoids. Findings suggest delaying harvest past technological maturity could confer greater aromatic intensity and complexity. The analytical approach used here appears promising for future studies on other grape varieties and other factors that could influence aroma, such as viticultural practices and environmental conditions.

Particle film treatments on ‘Assyrtiko’ grapevines enhance physiology and grape attributes in Santorini Island

Like many viticultural regions of the Mediterranean region, Santorini is also affected by climate change. These changing climatic conditions pose challenges to adapt the island’s traditional viticulture practices to the new climatic conditions of climate change, which will intensify in the future, with the use of short- and long-term solutions with a sustainable manner respecting the tradition and the island’s landscape. Viticulture in this region copes with high temperatures, heat waves and drought which affect the maturity process, the technological maturity, as well as the physiology of the grapevine. The aim of this study was to investigate the effects of kaolin and calcium carbonate foliar application on water relations, photosynthesis and berry composition of vines of grape cultivar ‘Assyrtiko’, trained with the traditional training system ‘Kouloura’, under drought conditions and vertical shoot positioned training system in Santorini. The effects of foliar application with kaolin and CaCO3 on vines of grape cultivar ‘Assyrtiko’ were evaluated, focusing on the impact on the vine’s physiology attributes, grape quality, and environmental sustainability. Based on the results of the present study, there were statistically significant differences on vine water stress where the foliar application of inert films reduced water stress during the three studied years. Kaolin and CaCO3 increased significantly the photosynthesis and stomatal conductance of the vines in comparison to the control. Furthermore, the foliar application with inert minerals has reduced sunburn and pest damage. The results of the present study confirm that the application of kaolin and CaCO3 constitutes an effective and economical solution for the water saving of the vines in dry conditions, while at the same time, it can improve the physiology of the plant and preserve the qualitative and quantitative attributes of the grapes. The foliar use of inert particle films on Santorini’s traditional vineyards could consist a sustainable and effective alternative to mitigate the effects of climate change which have intensified over the last decades in the region.

Integrating Spectral Sensing and Systems Biology for Precision Viticulture: Effects of Shade Nets on Grapevine Leaves

This study investigates how grapevines (Vitis vinifera L.) respond to shading induced by artificial nets, focusing on physiological and metabolic changes. Through a multidisciplinary approach, grapevines’ adaptations to shading are presented via biochemical analyses and hyperspectral data that are then combined with systems biology techniques. In the study, conducted in a ‘Moscatel Galego Branco’ vineyard in Portugal’s Douro Wine Region during post-veraison, shading was applied and predawn leaf water potential (Ψpd) was then measured to assess water stress. Biochemical analyses and hyperspectral data were integrated to explore adaptations to shading, revealing higher chlorophyll levels (chlorophyll a-b 117.39% higher) and increased Reactive Oxygen Species (ROS) levels in unshaded vines (52.10% higher). Using a self-learning artificial intelligence algorithm (SL-AI), simulations highlighted ROS’s role in stress response and accurately predicted chlorophyll a (R2: 0.92, MAPE: 24.39%), chlorophyll b (R2: 0.96, MAPE: 17.61%), and ROS levels (R2: 0.76, MAPE: 52.17%). In silico simulations employing flux balance analysis (FBA) elucidated distinct metabolic phenotypes between shaded and unshaded vines across cellular compartments. Integrating these findings provides a systems biology approach for understanding grapevine responses to environmental stressors. The leveraging of advanced omics technologies and precise metabolic models holds immense potential for untangling grapevine metabolism and optimizing viticultural practices for enhanced productivity and quality.

Sustainability in the winemaking industry and the assessment of grape seed characteristics during processing: Evidence from Azerbaijan

In the context of Azerbaijan’s evolving winemaking landscape, this study investigates the sustainability of viticulture with a particular focus on grape seeds, which are crucial for grapevine propagation, oil extraction, and overall vineyard health. The research aimed to examine the morphological, technological, and biochemical characteristics of grape seeds to optimise grape production methods and promote sustainable viticultural practices. To achieve this, seed samples from twelve grape varieties, both local and introduced, were carefully collected and analysed under varying irrigation conditions, including both irrigated and rainfed settings, to allow for a comprehensive assessment. The investigation revealed significant effects of irrigation on seed properties. Specifically, seeds from irrigated grapes were found to be larger, heavier, and richer in oil content compared to those from rainfed grapes. Detailed analyses showed that the nitrogen content of the seeds ranged from 0.96% to 1.46%, cellulose content varied from 18.8% to 25.3%, ash content ranged from 1.9% to 3.1%, nitrogenous compounds fluctuated between 5.5% and 7.2%, and non-nitrogen extractive substances registered between 16.6% and 22.0%. Notably, correlations between seed properties and the efficiency of cold press oil extraction were identified, providing valuable insights. This research ultimately contributes to the advancement of sustainable viticulture practices in Azerbaijan, ensuring the long-term health and productivity of vineyards within the region

Environmental impact assessment of horse and mechanical traction for vineyard cultivation

In the European Union, energy consumption in agriculture and forestry is less intense than in other economic sectors. However, fossil and non-renewable sources, particularly oil, are predominant, with higher percentages than in different economic sectors. In this context, this study aims to compare the environmental impact generated by equine and mechanical traction for viticulture practices in an organic production context, using life cycle assessment (LCA). Three scenarios were considered: business as usual (i.e., tractor-grown grapes) and horse-grown grapes but with two feeding options (tractor-grown hay and horse-grown hay). The results show that the tractor-grown grape scenario has higher impacts in five impact categories whereas the horse-grown scenario shows higher Global Warming, and to a minor extent Land use. Specifically, the worst results of the control scenario are in the mid-point category of Inorganic Respiratory due to fuel use, which produces P M 2.5. Fuel use is also the cause of the highest environmental burdens in other categories such as terrestrial Ecotoxicity. A sensitive analysis of the results was performed considering the endpoint damage categories. The outcomes show that, in general, the impact of horses is quite stable even under potentially different conditions. Some categories (ecosystem quality, global impact) are only slightly affected by variation in growth time, while all other categories (human health, resources, climate change) experience greater variation.

Challenges in viticulture practices in a changing environment: Can green waste amendment benefit soil properties of vineyards in the Mediterranean?

In Southeastern France, viticulture is of great social, cultural, and economic importance. This sector is threatened by climate change particularly in the Mediterranean (longer droughts and more frequent heat waves) where soils are poor in organic matter and weakly developed. Since organic amendment can strongly modify soil properties and consequently the final products (grapes and wine), the effects of sustainable practices on soil characteristics have to be carefully assessed. This seasonal field survey focuses on the effects green waste amendment (GWA), i.e. semi-composted green wastes, have on vineyard soil functionality. The effects of GWA were compared with those of grass cover (GC), known as a sustainable practice. Soils were collected in vineyards under organic practices (Bouches-du-Rhône and Var, France) over four seasons and physico-chemical (Total C and N, pHwater, pHKCL, EC, WHC, copper content and soil organic carbon SOC) and biological (microbial respiration and biomass, microbial catabolic structure, earthworm abundance and biomass) properties were characterized. Both practices were beneficial to soil physicochemical properties. For example, under both practices, higher (2 fold) Total N and SOC on late spring were observed. Both GWA and GC favored soil microbial communities, with microbial respiration having doubled and tripled on late spring. Similar results were observed for microbial biomass and both bacterial and fungal catabolic diversities (increased approximately by half) over summer. These benefits were particularly prominent during drought season (June and August), and probably linked to a shift in microbial communities as revealed by catabolic profiles. GWA also favored abundance and biomass of earthworm during winter. These findings reveal the potential GWA to counteract the effect of tillage, to mitigate the stress from drought and to improve overall soil functionality in vineyards.

Deciphering Terroirs’ Code: Vineyard Site Selection for Phenolic Performance in ‘Kalecik Karası’ Grape Cultivar (V. vinifera L.)

AbstractUnderstanding the complex interplay between environmental factors and grape quality is crucial for the viticulture industry, as it directly influences wine quality and the distinctiveness of products. This significance underpinned our comprehensive study, which aimed to dissect the relationships between ‘terroir’, including the altitude, regional climate, soil characteristics, vineyard management practice, and the composition of grapes in cv. ‘Kalecik Karası’ (Vitis vinifera L.). Six vineyard sites ranging from 115 to 1180 m altitude were studied. Total soluble solids (TSS, °Brix) titratable acidity, pH and color index of red grapes (CIRG) were evaluated as the main maturity indices and phenolic composition based on anthocyanin and tannin was analyzed. According to the results of the study, we deduced the critical importance of adopting region-specific viticultural practices tailored to the unique environmental conditions of each terroir. This approach not only optimizes grape quality but also accentuates the uniqueness of the wines produced, reflecting the inherent qualities of their origin. The highest altitude Nevşehir (1180 m) showed high levels of total and extractable anthocyanin highlighting the region’s favorable conditions for these compounds (355.26 mg kg−1 and 364.00 mg kg−1), while exhibiting the second lowest skin tannin (1979.40 mg kg−1 and 2180.78 mg kg−1) in both years. Particularly for cultivars like ‘Kalecik Karası’, our study demonstrated how specific terroirs could significantly affect their phenolic composition and, consequently, wine quality. By aligning viticultural practices with the distinct characteristics of each terroir, producers can enhance both the quality and distinctiveness of their wines. This emphasizes the necessity of ongoing research and adaptation in viticultural strategies to fully harness the potential of diverse grape varieties and terroirs, ensuring the production of high-quality wines that truly reflect their origin.

Setting the morphologic quality limits enabling accurate classification of charred archaeological grape seeds

This study investigates the morphological changes in grape pips resulting from various charring conditions. Employing high-resolution scanning combined with morphometric measurements for morphological analysis, we aimed to understand the effects of charring on grape pips. Our morphometric analysis demonstrated significant alterations in seed shape above 250 °C. The length–width ratio and the occurrence of cracks notably changed, providing a basis for assessing charring conditions. In addition, applying a machine learning classification method, we determined that accurate classification of grape varieties by the morphometric analysis method is feasible for seeds charred at up to 250 °C and 8 h. Integrating the morphometric changes and temperature ranges suitable for classification, we developed a sorting model for archaeological seeds. By projecting length–width ratios onto a curve calculated from controlled conditions, we estimated charring temperatures. Approximately 50% of archaeological seeds deviated from the model, indicating drastic charring conditions. This sorting model facilitates a stringent selection of seeds fit for classification, enhancing the accuracy of our machine learning-based methodology. In conclusion, combining machine learning with morphometric sorting enables the identification of charred grape seeds suitable for identification by the morphometric method. This comprehensive approach provides a valuable tool for future research for the identification of charred grape seeds found in archaeological contexts, enhancing our understanding of ancient viticulture practices and grape cultivation.

From the vineyard soil to the grape berry surface: Unravelling the dynamics of the microbial terroir

While unique bacterial and fungal communities are identified in various vineyard habitats, including soils, roots, and trunks, the impact of soil microbiota on the structure of communities colonizing the fruit surface remains puzzling. Our focus encompasses three aspects: the influence of soil microbiota on the surface microbiota of berries, the patterns of co-occurrence across different biological kingdoms, and a comparative analysis of the soil microbiota’s impact on both endophytic and epiphytic fungi that colonize grape berries. The Aureobasidium and Alternaria genera dominated mature berries but were noticeably absent or in low abundance in soil, while Basidiomycota featured prominently in both vineyard soils and on grape berries. Comparisons between soil and grape berry microbiota challenged the notion of a direct connection, revealing low overlap. Co-occurrence analysis unveiled habitat-specific networks, emphasizing alternative sources for berry colonization. This echoes earlier reports of limited correlation in microbial communities between soil and grape berries. In this study, we broaden our inquiry by incorporating data from a published study. This enables us to conduct a comparative analysis of the soil fungal metagenome, focusing on the endophytic and epiphytic microbiota associated with grape berries. Regional comparisons demonstrated differences in community diversity and dissimilarity in microbial profiles, emphasize the influence of local conditions, suggesting that the microbial composition of vineyards is shaped by region-specific factors. These findings underscore the multifaceted nature of soil and grape microbiota interactions, offering crucial insights for advancing our comprehension of vineyard ecosystems and informing agricultural and viticultural practices.

Synthetic Aperture Radar in Vineyard Monitoring: Examples, Demonstrations, and Future Perspectives

Synthetic aperture radar (SAR) technology has emerged as a pivotal tool in viticulture, offering unique capabilities for various applications. This study provides a comprehensive overview of the current state-of-the-art applications of SAR in viticulture, highlighting its significance in addressing key challenges and enhancing viticultural practices. The historical evolution and motivations behind SAR technology are also provided, along with a demonstration of its applications within viticulture, showcasing its effectiveness in various aspects of vineyard management, including delineating vineyard boundaries, assessing grapevine health, and optimizing irrigation strategies. Furthermore, future perspectives and trends in SAR applications in viticulture are discussed, including advancements in SAR technology, integration with other remote sensing techniques, and the potential for enhanced data analytics and decision support systems. Through this article, a comprehensive understanding of the role of SAR in viticulture is provided, along with inspiration for future research endeavors in this rapidly evolving field, contributing to the sustainable development and optimization of vineyard management practices.

Bunch thinning and its influence on the shoots growth dynamics in some syrah wine variety clones

During the period 2020-2022, an experiment was conducted in the experimental vineyard of the Agricultural University – Plovdiv, and four clones of the wine variety Syrah, numbered 100, 174, 470 and 524, grafted on the SO4 rootstock were selected as the study object. During the „pea size“ phase, the green pruning operation – bunch thinning was applied. The shoots growth starts from the vegetation phase „first leaf appearance“ and ends at the „veraison“. The average duration is about 100 days, covering the period of May, June and July. It was found that the vine shoots from a clone 470 reached the greatest average length, V3 – 285, 265, 290 cm and V7 – 359, 336, and 380 cm, and those from a clone 100 were distinguished by the weakest growth, V1 – 197, 203 and 205 cm and V5 – 240, 228 and 245 cm. Differences were proven between the variants, both in the non-reduced (V1, V2, V3, and V4) and in those with reduced yields (V5, V6, V7, and V8), as after reducing the number of bunches, the length of the shoots was longer – high in all vines from the used Syrah clones. This study provides information on the relationship between the applied green pruning operation (bunch thinning) during the growing season and its effects on the vegetative growth. Balancing the vines bud load by controlling yield during the growing season is a preferred viticultural practice for increasing the grape quality. Keywords: Clones, Syrah, green pruning, bunch thinning, shoot growth

Vermicomposting as a Valorization Solution to the Winery Sector By-Products

Winemaking is one of the most relevant socio-economic activities in the world, particularly in countries such as Portugal, generating substantial amounts of by-products across its various phases. Managing these by-products presents significant environmental, ecological, and economic challenges. Vermicomposting, the use of earthworms to process and transform organic wastes into nutrient-rich end-products, provides a viable alternative for waste management within the wine sector. This bioprocess also produces vermicompost that enhances soil health and fosters optimal conditions for plant growth, thereby promoting resilient and sustainable viticulture practices. This review explores the various by-products produced by the vine and wine industry, highlighting the potential of vermicomposting. Remarkably, grape marc, the primary solid waste of the winemaking process, has been the most commonly vermicomposted material. In contrast, other vineyard and wine cellar by-products have been comparatively underutilized and understudied in this context. However, we hypothesize that all vine and wine industry by-products have vermicomposting potential, allowing for the production of fertilizers and soil amendments. This approach aligns with the principles of the circular economy, ensuring that all materials stemming from viticulture and wine production are valued and reused, thereby contributing to enhanced sustainability and the preservation of resources like soil.

Effects of Growing Areas, Pruning Wound Protection Products, and Phenological Stage on the Stilbene Composition of Grapevine (Vitis vinifera L.) Canes.

Applying plant protection products (PPP) on grapevine pruning wounds is a viticultural practice used to mitigate the spread of grapevine tuck disease, which is posing serious economic losses in the vine-wine industry. However, the impact of PPP on woody tissues remains unclear. Our study, conducted in two European vineyards, investigated the effects of Cuprocol, Tessior, Esquive, and Bentogran on stilbenes, in canes of Cabernet sauvignon and Syrah, at three phenological stages. Main stilbenes, quantified by HPLC-UV-DAD (1260 Agilent Infinity System) and identified by HPLC-ESI/MS (Thermo Scientific LCQ FLEET system), included E-resveratrol, E-ε-viniferin, E-piceatannol, and E-polydatin. Canes exhibited varying proportions of individual stilbenes, reflecting differences based on climatic conditions and phenological phases, rather than on the application of specific PPP. Vines grown in cool-climate conditions exhibited higher levels of E-resveratrol, whereas vines from the Mediterranean climate area exhibited higher levels of E-ε-viniferin. We also observed divergences in the accumulation trend of wood stilbenes throughout the season in canes collected in the two different growing areas.

Detection of Leak Areas in Vineyard Irrigation Systems Using UAV-Based Data

Water is essential for maintaining plant health and optimal growth in agriculture. While some crops depend on irrigation, others can rely on rainfed water, depending on regional climatic conditions. This is exemplified by grapevines, which have specific water level requirements, and irrigation systems are needed. However, these systems can be susceptible to damage or leaks, which are not always easy to detect, requiring meticulous and time-consuming inspection. This study presents a methodology for identifying potential damage or leaks in vineyard irrigation systems using RGB and thermal infrared (TIR) imagery acquired by unmanned aerial vehicles (UAVs). The RGB imagery was used to distinguish between grapevine and non-grapevine pixels, enabling the division of TIR data into three raster products: temperature from grapevines, from non-grapevine areas, and from the entire evaluated vineyard plot. By analyzing the mean temperature values from equally spaced row sections, different threshold values were calculated to estimate and map potential leaks. These thresholds included the lower quintile value, the mean temperature minus the standard deviation (Tmean−σ), and the mean temperature minus two times the standard deviation (Tmean−2σ). The lower quintile threshold showed the best performance in identifying known leak areas and highlighting the closest rows that need inspection in the field. This approach presents a promising solution for inspecting vineyard irrigation systems. By using UAVs, larger areas can be covered on-demand, improving the efficiency and scope of the inspection process. This not only reduces water wastage in viticulture and eases grapevine water stress but also optimizes viticulture practices.

Influences of Cluster Thinning on Fatty Acids and Green Leaf Volatiles in the Production of Cabernet Sauvignon Grapes and Wines in the Northwest of China.

Cluster thinning has been widely applied in yield management and its effect on green leaf volatiles (GLVs) in wines has seldom been studied. GLVs are important flavor compositions for grapes and wines. This work aimed to investigate the impact of cluster thinning on these volatiles and their precursors in grapes and wines. Severe cluster thinning (CT1) and medium cluster thinning (CT2) were performed on Cabernet Sauvignon (Vitis vinifera L.) vines in two sites (G-farm and Y-farm) from Xinjiang province in the Northwest of China. The impact of cluster thinning treatments on the accumulation of GLVs and their precursors, long chain fatty acids (LCFAs) of grape berries and C6 volatiles, in resulting wines was investigated. Multivariate analysis showed that cluster thinning treatments induced significant changes in fruit and wine composition in both farms. In Y-farm, medium cluster thinning (CT2) significantly increased the average cluster weight of harvested berries. Additionally, both cluster thinning treatments (CT1 and CT2) increased fatty acids in harvested berries and CT2 led to an increase in C6 esters and a decrease in C6 alcohols in the wines of Y-farm under the warmer and drier 2012 vintage. However, the effect of cluster thinning was likely negative in G-farm due to its wetter soil and excessive organic matter. The treatments may be applicable for local grape growers to improve viticultural practices for the more balanced vegetative and reproductive growth of Cabernet Sauvignon grapevines. This work also provided further knowledge on the regulation of fatty acids and the derived C6 volatiles through the lipoxygenase (LOX) pathway.