Grape Yield Research Articles

Soil-climatic conditions of the vineyard and biochemical characteristics of the red dry wine ‘Kara-Koysu’ (Republic of Dagestan, Russian Federation)

ABSTRACT The article provides additional information that emphasizes the growing international interest in the impact of climate (temperature, humidity, precipitation, solar activity) on grape yields and the quality of terroir wine. The study deals with the climate gradient of the terroir of the Derbent region of the Republic of Dagestan (Russia), located on the terraced accumulative-coastal plain of the Caspian lowland, stretching for 160 km from north to south in a narrow strip between the coast of the Caspian Sea and the foothills. The influence of soil and climatic conditions on the biochemical characteristics of red dry wines ‘Kara-Koysu’ from Cabernet Sauvignon wingrapes of the 2019–2021 harvest was studied. The growing season occurred in dry, moderately humid conditions in 2019; hot, with a lot of precipitation in 2020 and more extreme conditions in 2021. The conditions of recent years have contributed to the change of almost all the studied indicators of tested wines. Studies have found that the climatic conditions of 2020–2021 were more favorable for obtaining a rich harvest, high-quality wines due to more UV light exposure and precipitation.

Using Legume-Enriched Cover Crops to Improve Grape Yield and Quality in Hillside Vineyards

Natural covering (NATC) has spread on hillside vineyards of central Italy as a replacement for tillage to reduce soil erosion, although it increased nitrogen and water needs. Therefore, in the current context of global warming, using cover crops (CCs) that require less water and provide nitrogen becomes crucial. The effects of two low-competition legume-enriched CCs in a rainfed hillside vineyard—a perennial legume–grass mixture (PLGM) and an annual legume cover crop of Trifolium alexandrinum (ALTA)—were compared with NATC over three years. PLGM and ALTA provided good levels of soil coverage, slightly lower than NATC, which had a negligible presence of legumes. PLGM and ALTA, due to low competition, enhanced vine vigor, resulting in thicker and wider canopies (as indicated by total leaf area and leaf layer number), higher pruning weight, and increased yield. PLGM and ALTA led to good qualitative levels, with higher grapes acidities, lower pH and total soluble solids content and, additionally, significantly higher yeast assimilable nitrogen content. In conclusion, implementing low-competition legume species in CCs is an effective tool to avoid soil erosion in a climate change scenario, leading to increased productivity, higher acidity, and improved nitrogen content in the grapes.

Investigating the Role of Cover-Crop Spectra for Vineyard Monitoring from Airborne and Spaceborne Remote Sensing

The monitoring of grape quality parameters within viticulture using airborne remote sensing is an increasingly important aspect of precision viticulture. Airborne remote sensing allows high volumes of spatial consistent data to be collected with improved efficiency over ground-based surveys. Spectral data can be used to understand the characteristics of vineyards, including the characteristics and health of the vines. Within viticultural remote sensing, the use of cover-crop spectra for monitoring is often overlooked due to the perceived noise it generates within imagery. However, within viticulture, the cover crop is a widely used and important management tool. This study uses multispectral data acquired by a high-resolution uncrewed aerial vehicle (UAV) and Sentinel-2 MSI to explore the benefit that cover-crop pixels could have for grape yield and quality monitoring. This study was undertaken across three growing seasons in the southeast of England, at a large commercial wine producer. The site was split into a number of vineyards, with sub-blocks for different vine varieties and rootstocks. Pre-harvest multispectral UAV imagery was collected across three vineyard parcels. UAV imagery was radiometrically corrected and stitched to create orthomosaics (red, green, and near-infrared) for each vineyard and survey date. Orthomosaics were segmented into pure cover-cropuav and pure vineuav pixels, removing the impact that mixed pixels could have upon analysis, with three vegetation indices (VIs) constructed from the segmented imagery. Sentinel-2 Level 2a bottom of atmosphere scenes were also acquired as close to UAV surveys as possible. In parallel, the yield and quality surveys were undertaken one to two weeks prior to harvest. Laboratory refractometry was performed to determine the grape total acid, total soluble solids, alpha amino acids, and berry weight. Extreme gradient boosting (XGBoost v2.1.1) was used to determine the ability of remote sensing data to predict the grape yield and quality parameters. Results suggested that pure cover-cropuav was a successful predictor of grape yield and quality parameters (range of R2 = 0.37–0.45), with model evaluation results comparable to pure vineuav and Sentinel-2 models. The analysis also showed that, whilst the structural similarity between the both UAV and Sentinel-2 data was high, the cover crop is the most influential spectral component within the Sentinel-2 data. This research presents novel evidence for the ability of cover-cropuav to predict grape yield and quality. Moreover, this finding then provides a mechanism which explains the success of the Sentinel-2 modelling of grape yield and quality. For growers and wine producers, creating grape yield and quality prediction models through moderate-resolution satellite imagery would be a significant innovation. Proving more cost-effective than UAV monitoring for large vineyards, such methodologies could also act to bring substantial cost savings to vineyard management.

Efficacy of Ascophyllum nodosum Seaweed Extracts on Growth, Yield and Quality Parameters in Thompson Seedless Grapes

The experiment was conducted on Thompson Seedless grafted on Dogridge rootstock planted at ICAR- National Research Centre for Grapes, Pune during the year 2021-2022. The experiments was carried out in completely randomized block design. Standard cultural practices were followed during the experimentation. The A. nodosum was applied with different concentration varies from 0.25 kg/ha to 1.25 kg/ ha at 4-6 inch cane growth, 8-14 inch cane growth (14 days after 1st spray), 10 days after fruit set, 2 weeks after 3rd spray, 2 weeks after 4th spray and Version Stage. The result obtained from this study showed that the chlorophyll content index (44.30 µmol/m²), leaf area index (1.88 cm2), bunch weight (216.16 g), berry diameter (14.83 mm), berry length (19.81 mm), yield/ha (16.86 ton), TSS (21.050 Brix) and Acidity (0.66%) were recorded higher in treatment treated with A.nodosum @ 0.75kg/ha. From this study, it is concluded that foliar application of A. nodosum @ 0.75 kg/ha recorded higher chlorophyll content in leaf and chlorophyll content index also helpful for improving and increasing yield and quality parameters in Grapes.

The Potential of Microorganisms for the Control of Grape Downy Mildew-A Review.

Plasmopara viticola (Berk.et Curtis) Berl. Et de Toni is the pathogen that causes grape downy mildew, which is an airborne disease that severely affects grape yield and causes huge economic losses. The usage of effective control methods can reduce the damage to plants induced by grape downy mildew. Biocontrol has been widely used to control plant diseases due to its advantages of environmental friendliness and sustainability. However, to date, only a few comprehensive reviews on the biocontrol of grape downy mildew have been reported. In this review, we summarize the biological characteristics of P. viticola and its infection cycle, followed by a detailed overview of current biocontrol agents, including bacteria and fungi that could be used to control grape downy mildew, and their control effects. Furthermore, potential control mechanisms of biocontrol agents against grape downy mildew are discussed. Lastly, suggestions for future research on the biocontrol of grape downy mildew are provided. This review provides the basis for the application of grape downy mildew biocontrol.

Environmental benefits of ozonated water for sustainable grapevine disease control: A life cycle and carbon sequestration analysis

The oxidative capacity of ozone makes it a highly effective biocide, widely used in the food and processing industry, as well as in drinking water plants. In a context of tighter restrictions on the use of synthetic plant protection products at the regulatory level, wineries are looking for alternative methods to control diseases, making the application of ozonated water an option to consider. To determine the environmental sustainability of this alternative vineyard disease control treatment, an environmental impact assessment was conducted using the Life Cycle Assessment (LCA) methodology. The assessment was carried out in a vineyard located in the D.O. Rías Baixas of Galicia, located in northwestern Spain. The analysis was conducted on the basis of two functional units: i) 1 kg of grapes and ii) 1 ha of land managed and using a cradle-to-gate boundary system. Ten impact categories were assessed using the ReCiPe method, except for the water scarcity indicator, which was quantified using AWARE.The environmental sustainability of the vineyard was further analyzed by measuring its carbon sequestration potential to obtain a more complete environmental profile. The RothC-26.3 model was chosen to estimate absolute carbon sequestration and annual sequestration rate from 2020 to 2040. Since the ozone-only scenarios lost all harvest, no environmental assessment was performed for such scenarios. For the remaining scenarios, the findings suggest that those using a combination of ozonated water and fungicides have the worst environmental performance due to notable reductions in grape yield and more frequent disease control interventions, particularly in certain scenarios. When evaluating environmental performance per hectare of land managed, the scenario using ozonated water with a limited number of disease control interventions exhibited the most favorable environmental profile, primarily due to reduced use of fungicides and disease control passes. In addition, the main contributors to the vineyard environmental profile identified were diesel fuel combustion during field operations, fertilizer use and production, and irrigation. In addition, the research indicates that the vineyard sequesters carbon annually, but this alone is insufficient to offset its greenhouse gas emissions. However, it is estimated that through the application of more appropriate soil management practices, the vineyard could achieve carbon neutrality and potentially increase soil carbon stocks over time.

Interplanting potato with grapes improved yield and soil nutrients by optimizing the interactions of soil microorganisms and metabolites.

Interplanting crops is the best method to grow crops synergistically for better utilization of land and agro-resources. Grape (Vitis vinifera) and potato (Solanum tuberosum L.) have highly efficient agricultural planting systems in China, however, how soil physicochemical properties and soil microbial communities and metabolites affect the output of grape-potato interplanting remained unknown. In this study, we employed three planting patterns (CK: grape monocropping; YY: grape interplanted with potato (variety 'Favorita'); LS: grape interplanted with potato (variety 'Longshu7')) at two experimental sites i.e., the Huizhou (2022) site and the Qingyuan site (2023). The grape variety for all planting patterns was 'Sunshine Rose'. Soil samples (top 0-20 cm) at both sites were collected to observe the diversity of bacterial communities and soil metabolites. Our findings revealed that, compared with monocropping, the interplanted systems resulted in higher concentrations of total nitrogen, available phosphorus, and available potassium and enhanced the activities of acid phosphatase, urease, and protease. The potato root exudates also altered the relative abundance of Bacillus, Kaistobacter, and Streptomyces in the rhizosphere. Among the soil metabolites, lipids and organic acids showed the most significant changes. Notably, 13-L-hydroperoxylinoleic acid is the key differentially abundant metabolite involved in the regulation of linoleic acid metabolism pathways. The association analyses of the metabolome, microbiome, and soil physicochemical properties revealed that the interactions of microbes and metabolites resulted in differences in the soil nutrient content, whereas the interactions of 13-L-hydroperoxylinoleic acid and Firmicutes improved the soil nutrient levels and bacterial composition in the interplanting systems. In summary, our findings demonstrated that intercropping grapes with potato 'Favorita' was better with respect to improving soil nutrients, soil enzyme activity, the diversity of soil bacteria, and soil metabolites without causing adverse impacts on grape yield. Overall, this study explained the physiological mechanisms by which soil microorganisms and metabolites promote potato growth in grape interplanting and provided new perspectives for the utilization of soil resources in vineyards.

Leaf Area Index, Photosynthesis and Chlorophyll Content Influences Yield and Quality of Nanasaheb Purple Seedless Grapes under Semi-arid Condition

Canopy management practices in grapes are crucial for achieving high-quality production. The study was conducted with different treatments of number of leaves above the bunch (10, 12, 14, 16, and >16 leaves). Significant variation was recorded on photosynthetic activity, yield and quality of Nanasaheb Purple Seedless grape variety. The increase in leaf number enhanced total leaf area and photosynthetic capacity while, it had negative impact on bunch weight, berry size and total soluble solids (TSS). Retaining 10 leaves above bunch with leaf area of 1980.00 cm2 /bunch resulted in maximum bunch weight (450.20 g), 50-berry weight (250.13 g) and yield/vine (13.60 kg) while, minimum bunch weight (400.00 g), 50-berry weight (222.30 g) and yield/vine (11.22 kg) were observed by retaining >16 leaves above the bunch. However, retaining 10 leaves above the bunch on a shoot with leaf area/shoot (2475.00 cm2), leaf area/vine (59400.00 cm2), leaf area/bunch (1980.00 cm2) and leaf area/g berry weight (4.36 cm2/g) were sufficient to obtain good quality production in Nanasaheb Purple Seedless grape variety spaced at 9 feet X 5 feet distance.

Study on the effect of pre harvest sprays of calcium chloride and organic acids on yield and shelf life of grape (Vitis vinifera L.) cv. thompson seedless

Study on the effect of pre harvest sprays of calcium chloride and organic acids on yield and shelf life of grape (Vitis vinifera L.) cv. thompson seedless

Response Superior Grape Yield and Quality to Organic and Inorganic Fertilization

Response Superior Grape Yield and Quality to Organic and Inorganic Fertilization

A precise grape yield prediction method based on a modified DCNN model

This paper presents an innovative method for predicting grape yield using a modified deep convolutional neural network (M−DCNN). This approach integrates advanced image processing techniques with deep learning algorithms to analyze high-resolution images of vineyards, enabling precise yield quantification. The M−DCNN model incorporates novel convolutional layers and activation functions to enhance accuracy and generalization capabilities. Extensive experiments were conducted using a varied dataset of grape varieties and vineyard conditions. The method involves image processing to identify grape clusters and monitor their growth at different stages. We evaluated the performance of several algorithms, including K-nearest neighbors (KNN), multinomial logistic regression (MLR), support vector machines (SVM), random forests (RF), deep convolutional neural network (DCNN), and M−DCNN, throughout the training and testing phases. The M−DCNN achieved the highest training accuracy at 97.35%, which represents a 0.85% improvement over the standard DCNN. Furthermore, in detecting grape berries, our method attained an average F1 score of 73.32% and coefficients of determination exceeding 0.98, showcasing high accuracy and precision. The results indicate that the M−DCNN model surpasses traditional yield estimation methods and existing machine learning models, affirming its potential to significantly enhance precision agriculture. This method offers a robust tool for accurate grape yield forecasting, facilitating informed decision-making in viticulture.

Greenhouse gas emissions and drivers of the global warming potential of vineyards under different irrigation and fertilizer management practices

In the context of global warming and low water and fertilizer utilization efficiency in vineyards, identifying the driving factors of global warming potential (GWP) and proper irrigation and fertilization management strategies are crucial for high grape yields and emission reduction. In this experiment, drip fertigation technology was used, including three irrigation levels (W3 (100% M, where M is the irrigation quota), W2 (75% M) and W1 (50% M)) and four fertilization levels (F3 (648 kg hm−2), F2 (486 kg hm−2), F1 (324 kg hm−2) and F0 (0 kg hm−2)). Traditional furrow irrigation and fertilization (CG) and rainfed (CK) treatments were used as control treatments. The results indicated that under the drip fertigation system, fertilization significantly increased the grape leaf chlorophyll relative content (SPAD) and leaf area index (LAI) within a fertilizer application of 0–486 kg hm−2. Irrigation primarily had a direct positive effect on the water-filled pore space (WFPS) in the 0–60 cm soil layer, and the residual soil nutrient content was mainly affected by fertilization. The vital stage for reducing greenhouse gas emissions was the fruit-inflating and fruit-rendering stages. The CG treatment not only failed to ensure high grape yield but also adversely affected the soil environment and the reduction of greenhouse gas emissions in the vineyard. Fertilization had a direct positive effect on the grape SPAD, LAI, yield, and soil residual nutrient content. GWP was primarily directly driven by SPAD, WFPS, and soil residual nutrient content, while grape yield was primarily directly driven by fertilization and SPAD. In conclusion, the W2F2 treatment (25 % reduced irrigation and 486 kg hm−2 of fertilization) of drip fertigation in the vineyard was the preferred irrigation and fertilizer management strategy for maintaining good vine vigor and balancing grape yield and environmental benefits.

Transcriptome analysis provides new insights into the berry size in ‘Summer Black’ grapes under a two-crop-a-year cultivation system

Southern China has high temperatures and receives concentrated rainfall; therefore, the two-crop-a-year cultivation system has been applied to grape production so as to resolve the problem of relative seasonal surplus of grape yield. However, a common issue associated with this technique is the tendency of the second season fruits to be smaller than the first season fruits. We here used the first and second season fruits of ‘Summer Black’ at different ripening stages as research materials. Phenotypic and histological analyses revealed fewer cell number occurring between 7 and 14 days post anthesis (DPA) in the second season fruits, which ultimately resulted in a smaller fruit size compared with the first season fruits. To unravel the mechanism underlying this phenomenon, first and second season fruits of four time periods (7, 14, 21, and 28 DPA) were selected for RNA-seq analysis. This analysis identified 10 431 differentially expressed genes (DEGs). These DEGs were classified into 9 clusters through GO and KEGG enrichment analyses. Then the time-ordered gene co-expression network (TO-GCN) analysis with the breadth-first search algorithm showed that DEGs in the GCN were divided into 8 levels. The DEGs of early berry development (L1–L3) were enriched in heat stress- and cell division-related pathways. The field investigation of effective accumulated temperature confirmed that the growth and development of the second season fruits were subjected to high temperature stress during 7–14 DPA. Moreover, based on the results of interactive analysis of TO-GCN and transcriptional regulation prediction of L1–L3 genes, we constructed a unique hierarchical regulatory network for the heat stress regulation of berry size. The expression level of 5 candidate genes was verified through qRT-PCR. Vitvi10g00469 (HSFB2A), Vitvi16g00982 (HSFB2A), Vitvi02g00387 (HSFB2B), Vitvi15g01542 (NTL9), and Vitvi06g00592 (DIVARICATA) were upregulated in 7–14 DPA, whereas Vitvi18g00777 (HSFB4) was downregulated in 7 DPA. These results suggest that during intense cell division, heat stress might act as a major factor causing a reduction in cell number, thereby ultimately resulting in the smaller size of the second season fruits.

Response of photosynthetic characteristics and yield of grape to different CO2 concentrations in a greenhouse.

Due to the enclosed environment of greenhouse grape production, the supply of CO2 required for photosynthesis is often insufficient, leading to photosynthetic downregulation and reduced yield. Currently, the optimal CO2 concentration for grape production in greenhouses is unknown, and the precise control of actual CO2 levels remains a challenge. This study aims to investigate the effects of different CO2 concentrations on the photosynthetic characteristics and yield of grapes, to validate the feasibility of a CO2 gas irrigation system, and to identify the optimal CO2 concentration for greenhouse grape production. In this study, a CO2 gas irrigation system combining CO2 enrichment and gas irrigation techniques was used with a 5-year-old Eurasian grape variety (Vitis vinifera L.) 'Flame Seedless.' Four CO2 concentration treatments were applied: 500 ppm (500 ± 30 µmol·mol-1), 700 ppm (700 ± 30 µmol·mol-1), 850 ppm (850 ± 30 µmol·mol-1), and 1,000 ppm (1,000 ± 30 µmol·mol-1). As CO2 concentration increased, chlorophyll a, chlorophyll b, and carotenoids in grape leaves all reached maximum values at 700 ppm and 850 ppm during the same irrigation cycle, while the chlorophyll a/b ratio was lower than at other concentrations. The net photosynthetic rate (Pn) and water use efficiency (WUE) of grape leaves were the highest at 700 ppm. The transpiration rate and stomatal conductance at 700 ppm and 850 ppm were significantly lower than those at other concentrations. The light saturation point and apparent quantum efficiency reached their maximum at 850 ppm, followed by 700 ppm. Additionally, the maximum net photosynthetic rate, carboxylation efficiency, electron transport rate, and activities of SOD, CAT, POD, PPO, and RuBisCO at 700 ppm were significantly higher than at other concentrations, with the highest yield recorded at 14.54 t·hm-2. However, when the CO2 concentration reached 1,000 ppm, both photosynthesis and yield declined to varying degrees. Under the experimental conditions, the optimal CO2 concentration for greenhouse grape production was 700 ppm, with excessive CO2 levels gradually inhibiting photosynthesis and yield. The results provide a theoretical basis for the future application of CO2 fertilization and gas irrigation techniques in controlled greenhouse grape production.

The influence of different methods of under-vine management on the structure of vegetation and the qualitative parameters of the grapes in the Moravian wine region

ABSTRACT The present article explores the importance of vineyard soil management. Studies on under-vine management have yielded a wide range of results, with some indicating potential benefits for vine growth and productivity. However, the methods of under-vine management and their specific effects on vineyard parameters require further research. The aim of this study is to evaluate the relationships existing between the different types of management of under-vine areas and the vegetation grown in this zone and to determine the effects of under-vine management on the yield and quality of Traminer grapevines. By examining various approaches, the research aims to provide insights into the optimising of vineyard management methods to achieve enhanced biodiversity and grape quality in this specific geographical context. The findings indicated that management of the under-vine area can impact the composition of plants, grape yield and quality. Under-row management had an effect on the number of plant species and their composition. The highest weight of bunches was found in MIX (a species from the Fabaceae family), while the lowest was found in the MECH treatment (bare soil). MULCH, MONO and MIX consistently had higher yeast assimilable nitrogen (YAN) in grapes than other treatments. In many of the evaluated parameters, the influence of the seasons was evident.

Effect of Pulsed Electric Field Pretreatment on the Concentration of Lipophilic and Hydrophilic Compounds in Cold-Pressed Grape Seed Oil Produced from Wine Waste.

Pretreatment of grape pomace seeds with a pulsed electric field (PEF) was applied to improve the extraction yield of cold-pressed grape seed oil. The effects of different PEF conditions, electric field intensities (12.5, 14.0 and 15.6 kV/cm), and durations (15 and 30 min) on the oil chemical composition were also studied. All PEF pretreatments significantly increased the oil yield, flow rate and concentration of total sterols (p < 0.05). In addition, similar trends were observed for total tocochromanols and phenolic compounds, except for PEF pretreatment under the mildest conditions (12.5 kV/cm, 15 min) (p < 0.05). Notably, the application of 15.6 kV/cm for 30 min resulted in the highest relative increase in oil yield and flow rate (29.6% and 56.5%, respectively) and in the concentrations of total tocochromanols, nonflavonoids, and flavonoids (22.1%, 60.2% and 81.5%, respectively). In addition, the highest relative increase in the concentration of total sterols (25.4%) was achieved by applying 12.5 kV/cm for 30 min. The fatty acid composition of the grape seed oil remained largely unaffected by the PEF pretreatments. These results show that PEF pretreatment effectively improves both the yield and the bioactive properties of cold-pressed grape seed oil.

The Arrestin-like Protein palF Contributes to Growth, Sporulation, Spore Germination, Osmolarity, and Pathogenicity of Coniella vitis.

Coniella vitis is a dominant phytopathogen of grape white rot in China, significantly impacting grape yield and quality. Previous studies showed that the growth and pathogenicity of C. vitis were affected by the environmental pH. Arrestin-like protein PalF plays a key role in mediating the activation of an intracellular-signaling cascade in response to alkaline ambient. However, it remains unclear whether palF affects the growth, development, and virulence of C. vitis during the sensing of environmental pH changes. In this study, we identified a homologous gene of PalF/Rim8 in C. vitis and constructed CvpalF-silenced strains via RNA interference. CvpalF-silenced strains exhibited impaired fungal growth at neutral/alkaline pH, accompanied by reduced pathogenicity compared to the wild-type (WT) and empty vector control (CK) strains. The distance between the hyphal branches was significantly increased in the CvpalF-silenced strains. Additionally, CvpalF-silenced strains showed increased sensitivity to NaCl, H2O2, and Congo red, and decreased sensitive to CaSO4. RT-qPCR analysis demonstrated that the expression level of genes related to pectinase and cellulase were significantly down-regulated in CvpalF-silenced strains compared to WT and CK strains. Moreover, the expression of PacC, PalA/B/C/F/H/I was directly or indirectly affected by silencing CvpalF. Additionally, the expression of genes related to plant cell wall-degrading enzymes, which are key virulence factors for plant pathogenic fungi, was regulated by CvpalF. Our results indicate the important roles of CvpalF in growth, osmotolerance, and pathogenicity in C. vitis.

Green-Nano Manganese and Its Impact on the Growth, Yield, and Fruit Properties of Flame Seedless Grapes

The present work aimed to evaluate green-nano manganese produced at the Microbial Biotechnology Department, National Research Centre, Egypt, and assess its impact on the growth, yield, and fruit properties of grapevines. To this end, two experiments were conducted. The first was microbiological, where several incorporation strategies were utilized to enrich the yeast with manganese, as follows: (1) manganese was added to the liquid medium (non-growth phase), and (2) manganese was added after 24 h of incubation (growth phase). The results showed that the non-growth phase had a reduced possibility of medium contamination. The manganese concentration in the yeast cells was increased due to manganese sulfate in the medium. The manganese incorporation in yeast cells was 99.93% (1.205 × 105) higher than that of the medium at 0.0195 g/L of manganese. Although the concentration of manganese in the medium raised the optical density (OD) of the yeast cell biomass, manganese sulfate had no passive influence on it. The second experiment was horticultural, where Flame Seedless grapevines were sprayed with frozen and active fresh yeast enriched with manganese that resulted from the microbiological experiment. Grapevines were sprayed twice a year at 10 or 20 cm3/L, and the results were compared with those for the mineral and chelate forms. The results demonstrated that yeast extracts in both forms showed positive effects on grapevine. The most effective treatment with regard to growth, yield, and fruit properties was frozen yeast enriched with manganese at 20 cm3/L, which yielded 10.14 and 12.6 kg/vine, compared with the control, which recorded 3.7 and 5.6 kg/vine in the two seasons, respectively.

Effect of foliar chelated forms spraying on grape yield and mineral status of shoots

The aim of this study was to evaluate the foliar chelated forms of Mg and Fe, on grape yield and mineral status of the shoots of vine cultivar Cardinal. Field trials were organized using a random block system with three variants, including a control (Variant I), each replicated three times. Foliar fertilizers were applied at a concentration of 0.5% on four occasions throughout the vegetation period: before and after blooming, during buckshot berry stage, and at the verasion stage. Over the ivestigation of three years, the application of foliar Mg and Fe fertilizers significantly influenced grape yield. The variant treated with Fe (VFe) demonstrated a higher average yield of 14.87 t/ha. Furthermore, a noticeable impact of foliar fertilizers on the concentration of analyzed elements in grapevine shoots was observed. Over the three-year period, the average content of macro elements, including nitrogen, phosphorus, calcium, magnesium, and iron, was higher in the treated variants compared to the control. Additionally, results from shoot tissue analysis confirmed the existence of an antagonistic relationship between magnesium and potassium.

Adapting the process based STICS model to simulate phenology and yield of table grapes- a high value fruit crop in a new emerging viticulture zone of South Asia

Plants strongly interact with their environment making phenology a sensitive indicator of climatic variability. Exploring the possibility of early prediction of phenological timings of table grape cultivars has huge socioeconomic benefits for the growers. Various statistical, mechanistic, and theoretical approaches have been used for parameterization of phenology models mainly for wine grapes. The studies on application of process-based models such as STICS (Simulateur mulTIdisciplinaire pour les Cultures Standard) particularly for table grapes and non-traditional viticulture zones are rather limited. The objective of this study was to calibrate the STICS model and evaluate its performance to simulate phenology and yield of four table grape cultivars in Pothwar- a new emerging viticulture zone of south Asia. For this, phenological timings, growth and yield responses were evaluated at two locations (Islamabad and Chakwal) for two consecutive vintages (2019 and 2020). Daily weather data, soil characteristics, genotype and crop specific data were recorded for model calibration. The results indicated a high robustness of the model for simulating table grapes phenology and yield in all cases. The model simulations indicated a satisfactory to high model efficiency (ME) of 0.69 to 0.94 with a prediction variability up to 4 days for growth stages, whereas ME for yield and pruning weight was 0.84 and 0.90, respectively. The model provided an efficient decision support tool (DST) though crucial predictions for viticulture industry. For instance, early maturity (up to 10 days), lesser yield (19–34 %) and pruning weight (19–42 %) for the warmer location (Chakwal) than for the colder Islamabad were simulated by the model with a high skill. The proximity of predicted values to observed values indicates that STICS is powerful tool for predicting vine phenology and yield, thus it provides a valuable insight in timely planning vineyards operations at key growth stages and selecting cultivars with higher yield for sustainable viticulture.