Search Results (44)

Apolygus lucorum is a major piercing–sucking pest in viticulture, yet its seasonal dynamics and outbreak risk in semi-arid wine-grape regions remain insufficiently understood. This study was conducted in a semi-arid wine-grape region of northwestern China during the 2024–2025 growing seasons. Adult density was monitored at 150 fixed sampling points across five landscape units. LOWESS-based phenological staging, stage-specific spatial interpolation, and an XGBoost-SHAP framework integrating meteorological, topographic, and grape phenological predictors were used to characterize spatiotemporal patterns and key predictors. A. lucorum density remained low in May, increased from June to July, peaked during August-September, and remained relatively high in October, with higher overall abundance in 2025 than in 2024. Spatial analyses revealed marked heterogeneity among landscape units, with high-density patches shifting across years and phenological phases. The XGBoost model showed good predictive performance, with an R² of 0.878 on the independent test set and a mean GroupKFold cross-validation R² of 0.869 ± 0.014. SHAP analysis identified grape phenology, elevation, relative humidity, sunshine duration, and temperature as the leading predictors of model-predicted density. PDP and ICE analyses showed higher predicted counts during later phenological periods, at lower elevations, and under higher relative humidity, particularly around 55%. Two-dimensional PDPs further indicated that high predicted densities mainly occurred under combinations of higher relative humidity, later phenological timing, moderate-to-high temperature, longer sunshine duration, and lower elevation. These findings provide a scientific basis for implementing precision-integrated pest management strategies in semi-arid viticultural regions, where monitoring relative humidity during critical phenological windows can serve as an early warning indicator for impending outbreaks. Full article

Global climate change poses a significant threat to viticulture, primarily due to high temperatures. This study examined temperature-induced changes in phenolic profiles in berries of three wine grape cultivars under 25, 35, and 45 °C for 0–48 h using HPLC-ESI-MS/MS. To investigate the molecular response to severe heat stress, transcriptomic analysis was conducted in Cabernet Sauvignon berries subjected to a 45 °C treatment. Results showed that the 45 °C treatment decreased the levels of anthocyanins (particularly delphinidin-3-O-glucoside and cyanidin-3-O-glucoside) in grape berries. Acylated anthocyanins, such as malvidin-3-O-(6-acetyl)-glucoside, exhibited enhanced stability at elevated temperatures. Additionally, high temperatures increased the levels of protocatechuic and gentisic acids and decreased those of rutin, ferulic acid, and p-coumaric acid. Transcriptomic and qRT-PCR analyses revealed that the expression of OMT, LDOX, GST, F3′5′H, and 3AT was positively correlated with changes in anthocyanin levels under high temperatures, suggesting their roles in the observed phenolic alterations. These findings highlight the molecular responses of winegrapes to heat stress, providing a foundation for future viticulture strategies under changing climatic conditions. Full article

Over two years, a randomized complete block field trial tested deficit irrigation [I: 70% ETc; NI] and ammonium nitrate [N₀, N₆₀, N₁₂₀; 0, 60, 120 kg N ha⁻¹] application in two northern Greece winegrape vineyards of cv. ‘Xinomavro’ (XM) and cv. ‘Cabernet Sauvignon’ (CS). Leaf-blade δ¹⁵N was measured at berry set, bunch closure, veraison, and technological maturity; berry-juice (must) δ¹⁵N at technological maturity and dormant cane δ¹⁵N in winter were also determined. In the first year, δ¹⁵N was additionally measured in petioles, unripe berries, trunks, and roots, along with arbuscular mycorrhizal fungal (AMF) colonization of fine roots. Fertilization increased δ¹⁵N in leaf blades and canes, whereas berry-juice δ¹⁵N responded weakly and inconsistently. Irrigation marginally lowered cane δ¹⁵N; cane δ¹⁵N varied between years, and berry-juice δ¹⁵N showed the highest variability across treatments. At berry set, intravine discrimination was evident: young berries and leaf blades were enriched, while fine roots and woody tissues were depleted. Root δ¹⁵N responses differed between cultivars and depended on AMF colonization in XM. Leaf and cane δ¹⁵N were positively related to vine N status, yield, and pruning weight but negatively to agronomic N-use efficiency indices. These findings indicate that δ¹⁵N serves as an integrative proxy of N cycling processes and fertilizer-use efficiency in vineyards, with potential implications for the assessment and optimization of sustainable vineyard management practices in the context of climate change. Full article

This study examined clonal variation in Vitis vinifera L. cv. ‘Merzifon Karası’, a Turkish wine grape. Thirty-two clones were evaluated for key growth and enological characteristics, including cluster structure, berry attributes, yield components, millerandage index, and berry skin color. Considerable variability was observed in cluster weight (95.8–254.1 g), berry weight (0.64–3.06 g), and millerandage index (1.35–9.77), highlighting the importance of clonal selection for optimizing fruit set, cluster compactness, and overall vineyard performance. Promising clones, such as F13/29, K11/27, and H20/24, combined high yield, well-formed clusters, and low millerandage indices, whereas clone K13/10 exhibited exceptional uniformity in fruit set, achieving the lowest millerandage index. Incorporating berry skin color characteristics further identified K11/27, F13/29, and K13/10 as particularly favorable for both productivity and winemaking quality due to their dark berries, consistent fruit set, and well-formed clusters. These findings illustrate the potential of targeted clonal selection to enhance sustainable viticulture and improve fruit quality in ‘Merzifon Karası’. Full article

Accurate assessment of a crop’s water requirement is essential for optimising irrigation scheduling and increasing the sustainability of water use. The crop coefficient (K_c) is a dimensionless factor that converts reference evapotranspiration (ET₀) into actual crop evapotranspiration (ET_c) and is widely used for irrigation scheduling. The K_c reflects canopy cover, phenology, and crop type/variety, but is difficult to measure directly in heterogeneous perennial systems, such as vineyards. Remote sensing (RS) products, especially open-source satellite imagery, offer a cost-effective solution at moderate spatial and temporal scales, although their application in vineyards has been relatively limited due to the large pixel size (~100 m²) relative to vine canopy size (~2 m²). This study aimed to improve grapevine K_c predictions using vegetation indices derived from harmonised Sentinel-2 imagery in combination with spectral unmixing, with ground data obtained from canopy light interception measurements in three winegrape cultivars (Shiraz, Cabernet Sauvignon, and Chardonnay) in the Barossa and Eden Valleys, South Australia. A linear spectral mixture analysis approach was taken, which required estimation of vine canopy cover through beta regression models to improve the accuracy of vegetation indices that were used to build the K_c prediction models. Unmixing improved the prediction of seasonal K_c values in Shiraz (R² of 0.625, RMSE = 0.078, MAE = 0.063), Cabernet Sauvignon (R² = 0.686, RMSE = 0.072, MAE = 0.055) and Chardonnay (R² = 0.814, RMSE = 0.075, MAE = 0.059) compared to unmixed pixels. Furthermore, unmixing improved predictions during the early and late canopy growth stages when pixel variability was greater. Our findings demonstrate that integrating open-source satellite data with machine learning models and spectral unmixing can accurately reproduce the temporal dynamics of K_c values in vineyards. This approach was also shown to be transferable across cultivars and regions, providing a practical tool for crop monitoring and irrigation management in support of sustainable viticulture. Full article

Rootstocks are widely used in viticulture as an agronomic measure to cope with biotic and abiotic stresses. In winegrapes, the aroma is one of the major factors defining the quality of grape berries and wines. In the present work, the grape aroma and wine aroma of Cabernet Sauvignon (CS) grafted on three rootstocks were investigated to inform the selection of rootstocks to utilize. 1103P, 5A, and SO₄ altered the composition of aromatic volatiles in CS grapes and wines. Among them, 5A and SO₄ had less effect on green leaf volatiles in the berries and wines, while 1103P increased green leaf volatile concentrations, up-regulating VvADH2 expression in both vintages. VvLOXA, VvLOXC, VvHPL1, VvADH1, VvADH2, and VvAAT were co-regulated by vintage and rootstock. Orthogonal partial least squares regression analysis (OPLS-DA) showed that the differential compounds in CS/1103P and CS berries were dominated by green leaf volatiles. Furthermore, the concentrations of 1-hexanol in the CS/1103P wines were significantly higher than in the other treatments in the two vintages. 1103P altered the expression of genes in the LOX-HPL pathway and increased the concentration of grape green leaf volatiles such as 1-hexanol and 1-hexanal, while vine vigor also affected green leaf volatile concentrations, the combination of which altered the aromatic composition of the wine and gave it more green flavors. Full article

During the automated picking of table grapes, the automatic recognition and segmentation of grape pedicels, along with the positioning of picking points, are vital components for all the following operations of the harvesting robot. In the actual scene of a grape plantation, however, it is extremely difficult to accurately and efficiently identify and segment grape pedicels and then reliably locate the picking points. This is attributable to the low distinguishability between grape pedicels and the surrounding environment such as branches, as well as the impacts of other conditions like weather, lighting, and occlusion, which are coupled with the requirements for model deployment on edge devices with limited computing resources. To address these issues, this study proposes a novel picking point localization method for table grapes based on an instance segmentation network called Progressive Global-Local Structure-Sensitive Segmentation (PGSS-YOLOv11s) and a simple combination strategy of morphological operators. More specifically, the network PGSS-YOLOv11s is composed of an original backbone of the YOLOv11s-seg, a spatial feature aggregation module (SFAM), an adaptive feature fusion module (AFFM), and a detail-enhanced convolutional shared detection head (DE-SCSH). And the PGSS-YOLOv11s have been trained with a new grape segmentation dataset called Grape-⊥, which includes 4455 grape pixel-level instances with the annotation of ⊥-shaped regions. After the PGSS-YOLOv11s segments the ⊥-shaped regions of grapes, some morphological operations such as erosion, dilation, and skeletonization are combined to effectively extract grape pedicels and locate picking points. Finally, several experiments have been conducted to confirm the validity, effectiveness, and superiority of the proposed method. Compared with the other state-of-the-art models, the main metrics $F1$ score and mask mAP@0.5 of the PGSS-YOLOv11s reached 94.6% and 95.2% on the Grape-⊥ dataset, as well as 85.4% and 90.0% on the Winegrape dataset. Multi-scenario tests indicated that the success rate of positioning the picking points reached up to 89.44%. In orchards, real-time tests on the edge device demonstrated the practical performance of our method. Nevertheless, for grapes with short pedicels or occluded pedicels, the designed morphological algorithm exhibited the loss of picking point calculations. In future work, we will enrich the grape dataset by collecting images under different lighting conditions, from various shooting angles, and including more grape varieties to improve the method’s generalization performance. Full article

Agresto is the unfermented juice traditionally obtained from boiled unripe grapes, typically using fruit that would otherwise be discarded, and enriched with spices, herbs, and fruit. In this study, the phenolic profile, antioxidant and antibacterial activity, and volatile organic compounds (VOCs) of Agresto produced from two grape varieties (Sangiovese, and Vermentino) harvested in Mount Amiata (Tuscany) were evaluated. Agresto from Vermentino showed a higher total phenolic content (TPC), 1.31 mg GAE/mL, as well as a greater total flavonoid and flavonol content and FRAP activity compared to Agresto from Sangiovese. The highest ORAC value was observed in Agresto from Vermentino, 41.01 mg TE/mL, compared to that from Sangiovese. TPC, flavonols, apocarotenes, sulfur derivatives, and non-terpene derivatives were positively correlated with antimicrobial activity against E. coli, FRAP, and ORAC. Overall, our results showed that grape variety significantly influences the chemical composition of Agresto, particularly in terms of both VOCs and phenolic compounds. The observed variations in phenolic composition also affected the antioxidant and antimicrobial activity of Agresto. These experimental findings clearly suggest the utmost importance of identifying the optimal chemical profile of “unripe grapes” used as raw material for Agresto production, considering both variety and the specific ripening degree achievable through vine green harvesting. Full article

Drama represents one of the distinct winegrape regions in the continuous growth of northern Greece. Yet, little is known about grape, must, and wine quality in various parts of the region. Determining the physicochemical characteristics of the Merlot, Cabernet Sauvignon, and Agiorgitiko grape varieties grown in different locations in the area across two vintages, their chromatic characteristics, phenolic profile, and organoleptic characteristics were the goal of this study. The results reveal a high variation in the physicochemical characteristics of must and wine among the locations. The location affects the profile of phenolic compounds with procyanidin B2, catechin, procyanidin B3, procyanidin B1, epicatechin, and gallic acid being present in high amounts. Merlot wines from the location with the highest altitude showed a higher amount of quantified phenolics. Altitude positively affected the yeast assimilable nitrogen (YAN) levels and negatively the wine’s purple hue. Moreover, the grape weight negatively affects the levels of some of the quantified phenolic compounds. On the other hand, both altitude and YAN positively impact the taste of wines. The altitude represents a significant parameter in the location studied that influences the quality parameters and taste of the wines. As part of climate adaptation strategies for viticulture in the Drama region and other comparable regions, high-altitude vineyard development should be studied to preserve the grape’s acidity and counteract warming trends. Full article

Algin is the most abundant substance in alga. Alginate lyase degrades algin and produces algin monosaccharides, disaccharides, and oligosaccharides, which are widely used in bioenergy, food, medicine, and other fields. In this study, one Exiguobacterium strain isolated from rotten kelp exhibited a robust ability to degrade the alga. The sequencing of this strain revealed the presence of three different types of algin alginate lyase. Nevertheless, the expression of three genes in Escherichia coli revealed a lower alginate lyase activity compared to that of the original strain. After codon optimization, the gene with the highest activity of the three was successfully expressed in Pichia pastoris to produce recombinant EbAlg664. The activity of the recombinant enzyme in 5 L high-density fermentation reached 1306 U/mg protein, 3.9 times that of the original Exiguobacterium strain. The results of the enzymatic analysis revealed that the optimal temperature and the pH range of recombinant EbAlg664 were narrower compared to the original strain. Additionally, the presence of Cu²⁺ and Co²⁺ enhanced the enzymatic activity, whereas Mg²⁺ and Fe³⁺ exhibited inhibitory effects on the recombinant alginate lyase. The study offers a theoretical and practical foundation for the industrial-scale production of engineered Pichia pastoris with high alginate lyase activity. Full article

‘Xinomavro’ (V. vinifera L.) is an important native red wine grape variety in Northern Greece, particularly in PDO (protected designation of origin) regions. Despite its significance, there is limited research on the effects of pruning type and severity on ‘Xinomavro’ vine physiology, yield, and berry quality across diverse environmental conditions. This study aimed to address this knowledge gap and provide growers with crucial information for optimizing vineyard management practices. The study was conducted over two consecutive years (2016 and 2017) in a vineyard in Thessaloniki, Northern Greece. Four treatments (B12: 12 buds on 6 spurs, B24: 24 buds on 12 spurs, M12: 12 buds on 2 canes, and M24: 24 buds on 4 canes) combining two bud load levels (12 or 24 count nodes) and two pruning types (short spurs or long canes) were applied to ‘Xinomavro’ vines in a complete block randomized design. The vine water status, gas exchange, canopy characteristics, yield components, and berry composition were measured. Bud load and pruning type significantly influenced vine canopy development, microclimate, and yield components. Short pruning with high bud load (B24) resulted in denser canopies and higher yields, whereas cane pruning (M12 and M24) led to more open canopies and improved berry quality indicators. Treatment effects on berry composition were inconsistent across years but showed a tendency for higher anthocyanin and total phenol content in cane-pruned vines. This study demonstrates that pruning type (short or long fruiting units) may have a greater impact on vine growth, yield, and berry composition than bud load alone in ‘Xinomavro’ vines. Cane pruning appears to be a more effective strategy for achieving vine balance and potentially improving grape quality under given experimental conditions. Full article

Soil water balance (SWB) in woody crops is sometimes difficult to estimate with one-dimensional models because these crops do not completely cover the soil and usually have a deep root system, particularly when cropped under rainfed conditions in a Mediterranean climate. In this study, the actual crop evapotranspiration (ET_{c act}) is estimated with the soil water balance model SIMDualKc which uses the dual-K_c approach (relating the fraction of soil cover with the crop coefficients) to improve the estimation of the water requirements of a rainfed vineyard, using data from a deep soil profile. The actual basal crop coefficient (K_{cb act}) obtained using the SIMDualKc model was compared with the K_{cb act} estimated using the A&P approach, which is a simplified approach based on measurements of the fraction of ground cover and crop height. Spectral vegetation indices (VIs) derived from Landsat-5 satellite data were used to determine the fraction of ground cover (f_{c VI}) and thus the density coefficient (K_d). The SIMDualKc model was calibrated using available soil water (ASW) measurements down to a depth of 1.85 m, which significantly improved the conditions for using an SWB estimation model. The test of the model was performed using a different ASW dataset. A good agreement between simulated and field-measured ASW was observed for both data sets along the crop season, with RMSE < 12.0 mm and NRMSE < 13%. The calibrated K_cb values were 0.15, 0.60, and 0.52 for the initial, mid-season, and end season, respectively. The ratio between ET_{c act} and crop evapotranspiration (ET_c) was quite low between veraison and maturity (mid-season), corresponding to 36%, indicating that the rainfall was not sufficient to satisfy the vineyard’s water requirements. VIs used to compute f_{c VI} were unable to fully track the plants’ conditions during water stress. However, ingestion of data from remote sensing (RS) showed promising results that could be used to support decision making in irrigation scheduling. Further studies on the use of the A&P approach using RS data are required. Full article

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. Full article

This study introduced the application of concepts and methods from extreme value theory (EVT) to estimate the probability that daily minimum temperatures exceed springtime critical temperature thresholds for Pinot noir buds and young shoots as a function of springtime phenology. The springtime frost risk estimates were computed spatially for Pinot noir throughout the Willamette Valley (WV) American Viticultural Area (AVA) using a gridded dataset of historical daily minimum surface air temperature data. EVT-based springtime frost risk maps can inform vineyard-management operations by identifying those locations throughout a wine region with a low risk for any cold injury where remedial action is likely not necessary when there is a forecasted frost event. Frost risk estimates were computed for 1991–2021 and 1991–2022 to examine a potentially changed risk profile for springtime frost events throughout the WV AVA due to the April 2022 advective frost event. The April 2022 advective frost event influenced the risk profile throughout the AVA such that an event of its magnitude is now modelled to occur more frequently. The EVT-based risk analysis can be readily updated each year as new data become available. While spatially varying budbreak calculations facilitated computation of the spring frost risk estimates, the EVT approach profiled in this study does not necessarily depend on potentially uncertain predetermined budbreak date estimates. Gridded maps of extreme daily minimum temperature exceedances, reclassified relative to the springtime phenology critical temperature thresholds for Pinot noir, were readily combined with a ripening potential map to identify optimal areas for vineyard site selection throughout the WV AVA. When simultaneously evaluating Pinot noir ripening potential with springtime frost risk using historical data, the limiting factor for vineyard site selection throughout the WV AVA was frost risk, not ripening potential. The study approach is also applicable for other winegrape-growing regions, assessments of winter freeze risk and summertime heatwaves, and with non-gridded observed temperature datasets. Full article

Zinc enrichment of edible food products, through the soil and/or foliar application of fertilizers, is a strategy that can increase the contents of some nutrients, namely Zn. In this context, a workflow for agronomic enrichment with zinc was carried out on irrigated Vitis vinifera cv. Syrah, aiming to evaluate the mobilization of photoassimilates to the winegrapes and the consequences of this for winemaking. During three productive cycles, foliar applications were performed with ZnSO₄ or ZnO, at concentrations ranging between 150 and 1350 g.ha⁻¹. The normal vegetation index as well as some photosynthetic parameters indicated that the threshold of Zn toxicity was not reached; it is even worth noting that with ZnSO₄, a significant increase in several cases was observed in net photosynthesis (P_n). At harvest, Zn biofortification reached a 1.2 to 2.3-fold increase with ZnSO₄ and ZnO, respectively (being significant relative to the control, in two consecutive years, with ZnO at a concentration of 1350 g.ha⁻¹). Total soluble sugars revealed higher values with grapes submitted to ZnSO₄ and ZnO foliar applications, which can be advantageous for winemaking. It was concluded that foliar spraying was efficient with ZnO and ZnSO₄, showing potential benefits for wine quality without evidencing negative impacts. Full article