Grape Varieties Research Articles

Exploring the Interplay of Bud Load and Pruning Type in Shaping ‘Xinomavro’ (Vitis vinifera L.) Vine Growth, Yield, and Berry Composition

‘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.

Влияние концентрации и рецептуры макросолей в питательной среде на показатели регенерации меристем, на этапе ввода в культуру in vitro, у некоторых аборигенных донских сортов винограда

Abstract. Rare indigenous grape varieties are of significant value for viticulture, breeding and preservation of genetic material. Often, ancient grape varieties, due to prolonged vegetative propagation, are infected with one or more chronic diseases (viruses, phytoplasmas, bacterial cancer). The most reliable way to improve the health of such plants is the method of apical meristems in in vitro culture. In which, on artificial nutrient medium, it is necessary to regenerate the plant from isolated extremely small apical explants (about 50-100 microns). One of the most important components of nutrient medium are macroelements. Not only their quantity is of great importance, but also the compounds they represent, as well as the balance and ratio of all elements in the nutrient medium. In this regard, the purpose of our study was to study the characteristics of mineral nutrition of grape plants of native Don varieties in in vitro culture. To do this, we studied the effectiveness of the most commonly used nutrient media in microclonal propagation. The experiments were carried out on four rare native Don varieties Plechistik oboepolyi, Bessergenevskiy №10, Musketnyi and Durman. Protocols used: Murashige and Skuug (MS), McCown Wood Plant (WPM), Chee and Pool (C2D), Quoirin & lepoivre (QL) and Anton Rebrov (AR1). The nutrient media differed only in the composition of macrosalts; all other components were added in equal quantities. The varietal response of the studied varieties was different. The Plechistik oboepolyi and Bessergenevskiy №10varieties regenerated best, and the Musketnyi and Durman varieties regenerated more poorly. It has been established that the composition of macroelements significantly affects the regeneration and differentiation of shoots in apical meristems. For most varieties, the most stable results were observed when using WPM and AR1 nutrient media. The worst development of explants in all varieties in the study occurred on MS and C2D media. Key words: apical meristem, introduction into in vitro culture, regeneration of explants, recipes for nutrient media, concentration of macronutrients, native Don varieties

Agrobiological reaction of Centennial Seedless grape variety to changes in the numberof shoots and bunches on bushes

Agrobiological reaction of Centennial Seedless grape variety to changes in the numberof shoots and bunches on bushes

Amur Grape VaMYB4a-VaERF054-Like Module Regulates Cold Tolerance Through a Regulatory Feedback Loop.

Cold stress can limit the growth and development of grapevines, which can ultimately reduce productivity. However, the mechanisms by which grapevines respond to cold stress are not yet fully understood. Here, we characterized an APETALA2/ethylene response factor (AP2/ERF) which was shown to be a target gene of our previously identified VaMYB4a from Amur grape. We further investigated the molecular interactions between VaMYB4a and VaERF054-like transcription factors in grapes and their role in cold stress tolerance. Our results demonstrated that VaMYB4a directly binds to and activates the VaERF054-like gene promoter, leading to its enhanced expression. Moreover, we also explored the influence of ethylene precursors and inhibitors on VaERF054-like expression and grape cold tolerance. Our findings indicate that VaERF054-like contribute to cold tolerance in grapes through modulation of the ethylene pathway and the CBF signal pathway. Overexpression of VaERF054-like in Vitis vinifera 'Chardonnay' calli and transgenic grape lines resulted in increased freezing stress tolerance, confirming its role in the cold stress response. We further confirmed the interaction between VaMYB4a and VaERF054-like in vivo and in vitro. The co-transformation of VaMYB4a and VaERF054-like in grape calli demonstrates a synergistic interaction, enhancing the cold tolerance through a regulatory feedback mechanism. Our finding provides new insights into grape cold tolerance mechanisms, potentially contributing to the development of cold-resistant grape varieties.

Comprehensive amino acids profiling: Grape varieties grown in California and in Tuscany, Italy.

Twenty-three amino acids and glutathione were profiled in 33 juices: Cabernet sauvignon, Cabernet franc, and Merlot grown in Bolgheri, Tuscany, Italy, and Napa Valley, CA, as well as Petit Verdot grown in Napa Valley, CA. The method was carried out by online pre-column derivatization followed by ultra-high performance liquid chromatography with fluorescence detection; residual standard deviation values for repeatability (n=20) were<5%. All amino acids could be successfully separated in these samples within 18 min. The most abundant amino acids, PRO, γ-aminobutyric acid, and ARG, varied by two-, two-, and three-fold, respectively, across all of the grape juices sampled. Comparisons between grape juices based on their geographic origin and variety were made with principal component analysis and hierarchical cluster analysis. Merlot juices from both regions were correlated differently by amino acids profile than Cabernet sauvignon and Cabernet franc juices. The amino acids profile in Merlot juices was more similar between most sites in Bolgheri. In contrast, Cabernet sauvignon and Cabernet franc juices had a higher similarity between vineyards in Bolgheri and vineyards in Napa Valley. Overall, most of the amino acids quantified in Cabernet franc juices and, to a lesser degree, Cabernet sauvignon juices from Bolgheri and Napa Valley vineyards were strongly correlated with each other.

Закладка виноградника на основе принципов энерго-ресурсосбережения

Abstract. The article contains materials that form the basis of a feasibility study (FS) for laying a vineyard (from planting to fructification), developed according to the principle of energy and resource conservation provided for in the project assignment. The project documentation is being developed in order to optimize the complex of sequential technological operations and production processes aimed at creating a sustainably functioning viticultural economy. The general principles of energy and resource conservation include: the latest achievements of science and best practices in the field of viticulture, rational use of land funds, thanks to preliminary soil surveys, optimized varietal composition, design of plantings and compact placement of arrays with the prospect of irrigation, reduction of energy losses to the level of operationally unavoidable, the use of highly concentrated, complex agrochemicals and methods of their application, the availability of appropriate infrastructure, design estimates optimized with the prospect of improvement and modernization (energy and resource-saving object estimates), planned economic productivity of plantations, measures to maintain the economic fertility of soils corresponding to the biological requirements of grape culture, which determines the stability and productivity of perennial plantations. Methodological approaches and current methods, publications of a recommendatory nature used for the development of a feasibility study are indicated. The successive stages of the development of project documentation are considered, the techniques that contribute to reducing the costs of production processes are outlined. The recommended regionalized and promising assortment of grapes for the formation of highly productive stable ampelocenoses ensuring stable highly profitable functioning of enterprises of the grape-growing industry in the Krasnodar region is presented and justified. The recommended current varietal composition of plantings is compiled taking into account the edaphoclimatic conditions of the design object, the agrobiological characteristics of grape varieties, as well as taking into account current global trends in the organization of a sustainably functioning highly efficient industrial enterprise for the production of viticulture products. Keywords: ampelocenosis, project assignment, long-term planning, varietal policy, energy and resource conservation

Influence of edaphoclimatic conditions on the growth and development of the autochthonous Don grape variety Sibirkovyi

Influence of edaphoclimatic conditions on the growth and development of the autochthonous Don grape variety Sibirkovyi

Influence of Grape Heterogeneity on Berry Quality Traits in Table Grapes A Study on the ‘Alphonse Lavallée’ Variety

The study, conducted in 2023 at the vineyard of the Agricultural Research and Application Center of Tokat Gaziosmanpaşa University, focused on the Alphonse Lavallée grape variety, a significant cultivar among table grapes. The research aimed to assess the impact of berry density on various quality parameters. Grape berries were selected across five different density categories (Y0-Y4), including a control group, to evaluate their physical characteristics (including width, length, weight, firmness, and skin color), chemical properties (pH, total titratable acidity, and soluble solids content), and phytochemical attributes (encompassing total phenol content, total antioxidant capacity, and total monomeric anthocyanin levels). The findings revealed that critical quality indicators—namely, soluble solids content, pH, total antioxidant capacity, and total monomeric anthocyanin—were maximized under the Y4 treatment. In contrast, the highest total phenol content was recorded in the Y2 and Y3 treatments. These results underscore the importance of berry density and berry/skin volume as key determinants of grape berry quality. The study contributes valuable insights into the role of these factors in enhancing the overall quality of table grapes, particularly in the context of the Alphonse Lavallée variety.

Exploring the Biological Value of Red Grape Skin: Its Incorporation and Impact on Yogurt Quality.

The study was conducted to study the sustainability and enhanced nutrition gains obtained from incorporating grape skin powder (GSP) extracted from both Fetească Neagră and Rară Neagră grape varieties into yogurt. Grape skins are major leftovers from wineries, having high amounts of phenolic compounds and dietary fiber responsible for their ability to improve the characteristics of food. The research aimed to evaluate the effect of GSP addition at varying concentrations (0.5%, 1.0%, and 1.5%) on the yogurt's physicochemical properties, antioxidant activity, color parameters, and sensory attributes. Analysis revealed that both Fetească Neagră and Rară Neagră GSP increased the total phenolic content and antioxidant activity; however, Fetească Neagră showed greater improvements, with TPC reaching 1.52 mg GAE/100 g and DPPH inhibition up to 26.63%. Although slightly lower, TPC rose to 1.43 mg GAE/100 g and DPPH inhibition increased to 18.93% with Rară Neagră enhancing these parameters conversely. Color changes were observed in fortified yogurts where lightness decreased (L*) and redness increased (a*) due to the pH-dependent anthocyanin stability. Syneresis, indicative of yogurt's water-holding capacity, was reduced at higher concentrations of GSP from both varieties, suggesting improved textural integrity. Sensory evaluation indicated that consumers generally favored yogurts with lower concentrations of GSP. Yogurts fortified with Fetească Neagră GSP received higher overall preference, while those with Rară Neagră GSP were also well-received for their distinct flavor profiles when used at suitable levels. These results show that GSP from both types of grapes improves the nutritional value of yogurt and complies with the principles of sustainable food production through reutilizing agro-industrial waste.

Pollen biology and metaxenic studies on early maturing grape (Vitis vinifera) genotypes

The present experiment was conducted during 2020–21 and 2021–22 at ICAR-Indian Agricultural Research Institute, New Delhi to study the impact of open-, self-, and cross-pollination on metaxenic traits (berries) and the incidence of cleistogamy in grapes (Vitis vinifera L.). Seven different cross-combinations were used on the grape variety Pusa Navrang, which were planted at 3 m × 3 m spacing and trained on the Y-trellis training system. The experiment was laid out in a randomized block design (RBD) with four replications. The incidence of cleistogamy, berry set, retention percentage, and the metaxenia effect of pollen grains in different grapevine varieties, namely, Pusa Navrang (PN), Black Muscat (BM), Pusa Swarnika (PS), Beauty Seedless (BS), Perlette (PER), Male Hybrid (MH), were studied. Also, pollen quantity and viability were determined for the different grapevine varieties under study. Depending on the genotypes and whether the fruit set is obtained inside the covered flowers, cleistogamy was confirmed. A significantly higher berry set (40–85%) and retention (32–77%) were recorded in open- and self-pollinated flowers. The total number of pollens/anther in six grape genotypes ranged from 7916.62–23832.02, whereas the maximum active pollen rates were noted in the Male Hybrid (70.01%) and Black Muscat (66.80%). The pollens from the Beauty Seedless genotype exhibited significant enhancement of metaxenic traits such as berry set, retention, and size in Pusa Navrang. Therefore, utilizing Beauty Seedless as a pollen parent in grape breeding programmes holds promise for enhancing berry set and overall berry quality, thus enhancing the hybridization efficiency.

The study of biochemical composition of grape and wine from Armenian selectionvariety Nrneni

Background: In Armenia, autochthonous, modern cultivars, and wild grape populations are highly diverse. Different types of wine can be produced due to the climatic zones. Grapes are a popular fruit all over the world, consisting of bioactive compounds and antioxidants, such as proanthocyanidins, anthocyanins, flavonols, organic and phenolic acids, and stilbenes. It is well known that grape varieties have different yields as well as quantitative and qualitative characteristics of the berry, which impact the quality of wine. Objective: Conduct an in-depth study of Indigenous grape varieties and clones is essential in the development of the best wine. Our focus is to specifically study Nrneni, an artificially selected Armenian grape variety. P.K. Ayvazyan, G.P.Ayvazyan created this variety by crossing a combination of Alikante Bouchet and Cabernet Sauvignion with Saperavi. The resulting product has pulp and juice that are an intense red color. Methods: In the Ararat Valley region, the grapes were hand-harvested at the end of September once they reached full technical maturity. The wine was made by the classic red winemaking method. Physicochemical analyses of grape and wine were carried out by OIV methods. Organic acids were separated and identified using liquid chromatography. A photocalorimetric method was used to determine the total phenolic compounds. Results: The chemical composition of red wine made from Nrneni grapes was assessed. In the process of wine production, storage, and maturation, grapes produce a variety of other substances, including organic acids, polysaccharides, and polyphenols, some of which contribute to the wine's sensory properties (such as flavor, color, and taste) and health benefits. Grapes are excellent sources of bioactive compounds, especially polyphenols. The total and extractable anthocyanin and flavonoid content of the Nrneni grape variety was determined. The conducted studies showed that Anthocyanins were present in high amounts of 2366.4 mg/kg. Flavonoids were present in 10183.0 mg/kg in the 2022 vintage, and 3159.9 mg/kg and 12563.7 mg/kg in the 2023 vintage. Extractable anthocyanin and flavonoid amounts were 1135.87 and 4684.18 mg/kg in 2022, 1540.32 and 5836.67 mg/kg in 2023 respectively. These indicators are also high in the wine: 502.18mg/l and 2971.15mg/l in 2022 vintage, while 975.7and 4208 mg/l in 2023 vintage. Theoretical varieties are present in 8.9 g/l and 2.02 g/l in 2022, and 6.5 g/l and 1.6 g/l in 2023. Licosaccharides, acetic acids, citric acids, and succinic acids are produced by alcoholic and malolactic fermentation. Conclusion: There is a wide range of bioactive compounds in red grapes and red wine that have been shown to have potential health benefits. According to studies, the Nrneni grape variety and the wine produced with these grapes have functional and oenological potential due to their high levels of biologically active substances, such as phenolic compounds and organic acids. Keywords: bioactive compounds, grape, organic acids, phenolic compounds, red wine.

Red Grape By-Products from the Demarcated Douro Region: Chemical Analysis, Antioxidant Potential and Antimicrobial Activity against Food-Borne Pathogens.

Wine production is one of the most important agricultural activities. The winemaking process generates a considerable volume of different residues characterized as by-products, such as pomace, seeds, stems, and skins. By-products are rich in polyphenols with antioxidant and antibacterial properties and may act as bacteriostatic or bactericidal agents against food-borne pathogens, improving food safety by enhancing antibiotic efficacy and reducing bacterial resistance. The aim of this study was to evaluate the phenolic composition and antioxidant activity of grape components (skins, seeds, and stems) from three red grape varieties (Periquita, Gamay, and Donzelinho Tinto) and determine their antibacterial activity against antibiotic-resistant bacteria, including Escherichia coli in food-producing animals and Listeria monocytogenes from food products and food-related environments. Ten phenolic compounds were quantified in these red grape varieties, with specific compounds found in different parts of the grape, including phenolic acids and flavonoids. Flavonoids are abundant in seeds and stems, malvidin-3-O-glucoside being the main anthocyanin in skins. The ethanolic extract from the seeds showed in vitro concentration-dependent activity against reactive species like •NO and O2•-. Gamay extract was the most effective, followed by Donzelinho Tinto and Periquita. Extracts showed varying antibacterial activity against Gram-positive and Gram-negative bacteria, with stronger effects on Gram-positive bacteria. L. monocytogenes was more susceptible, while E. coli was limited to three strains. Seeds exhibited the strongest antibacterial activity, followed by stems. The results of our study provide evidence of the potential of grape by-products, particularly seeds, as sources of bioactive compounds with antioxidant and antibacterial properties, offering promising avenues for enhancing food safety and combating antibiotic resistance in food production and related environments.

Effects of Seaweed Applications on Phenological Development Stages and Total Effective Temperature in Yuvarlak Çekirdeksiz Grape Variety Grown in Siirt Conditions

This study was carried out on the Yuvarlak Çekirdeksiz grape variety grown in the Siirt University application vineyard. Three different times and four different doses [control (0 ppm), 1st application (1000 ppm before flowering), 2nd application (1000 ppm before flowering + 1000 ppm after flowering), 3rd application (1000 ppm before flowering + after flowering) 1000 ppm + veraison 1000 ppm)] applied liquid seaweed on phenological stages and its effects on Total Effective temperature (TET) were compared. When the phenological periods were compared with the control; It was determined that the first application took the full flowering phase three days earlier and the veraison phase six days earlier. The Total Effective Temperature value between full bloom and veraison was determined to be between 659.78-819.98 gd, and it was determined that the first application shortened the vegetation period compared to the control, while the other two applications extended the vegetation period.

Enantioselective-GCxGC determination of α-terpinyl ethyl ether in wine: Quantitative analysis and identification of main terpene precursors

The present study investigates the presence of α-terpinyl ethyl ether in wine and gives insights on the chemical processes leading to its formation. The analytical determination of (S)-α-terpinyl ethyl ether and (R)-α-terpinyl ethyl ether enantiomers was obtained by enantioselective comprehensive two-dimensional gas chromatography. Applying the two isomers as variables in combination with closely related terpenes, an accurate classification model of wines for the grape variety was successfully applied to a representative set of single-variety wine samples. Although presenting relatively low absolute concentrations, α-terpinyl ethyl ether (along with α-terpineol) resulted to be an inevitable and irreversible degradation product of linalool. In fact, a conversion study from enantiomerically pure (R)-linalool showed a major loss of the initial chiral configuration, i.e. only a very small enantiomeric excess characterized the product. α-Terpineol itself was also confirmed to be a precursor of α-terpinyl ethyl ether, however this process showed a smaller conversion over two weeks than from linalool, and without losses of the initial chiral configuration. In the real samples, the concentration of α-terpinyl ethyl ether was found to be much lower than that of α-terpineol, regardless of the alcohol-to-water ratio. Finally, olfactory descriptors were qualitatively attributed to each α-terpinyl ethyl ether enantiomer.

Diverse impact of topography and cultivation location on the polyphenolic profiles and certain sensory attributes of ‘País’ heritage wines from the Maule dryland region (Chile)

Polyphenols are compounds that have traditionally been related to sensory properties of wines. The synthesis of these secondary metabolites can be influenced by numerous factors, including the edaphoclimatic conditions of the growing area of vines. In this study, the effect of topography and cultivation location on the chemical composition and sensory perception of wines was determined. Different vineyards cultivating the ‘País’ grape variety were selected. This variety is of great historical heritage relevance in collections of different wine-producing countries. Three vine growing areas from each of three localities of a dryland region of Chile displaying either “Hilly” (slope 18–20 %) or “Valley” (slope less than 9%) topographies were selected. Resulting wines were analyzed chemically (spectrophotometry and HPLC-DAD) and sensorially (acceptability and CATA). A close relationship between edaphoclimatic conditions of the vine growing area and certain sensory properties of wines (color, mouthfeel but not aroma) was evidenced. By contrast, association between edaphoclimatic conditions of vine cultivation and the phenolic profile of the wine products was unclear. Furthermore, phenolic differences between the wines produced from vines grown at different topographical conditions were not significant.

The Use of Ultra-Fast Gas Chromatography for Fingerprinting-Based Classification of Zweigelt and Rondo Wines with Regard to Grape Variety and Type of Malolactic Fermentation Combined with Greenness and Practicality Assessment

In food authentication, it is important to compare different analytical procedures and select the best method. The aim of this study was to determine the fingerprints of Zweigelt and Rondo wines through headspace analysis using ultra-fast gas chromatography (ultra-fast GC) and to compare the effectiveness of this approach at classifying wines based on grape variety and type of malolactic fermentation (MLF) as well as its greenness and practicality with three other chromatographic methods such as headspace solid-phase microextraction/gas chromatography-mass spectrometry with carboxen-polydimethylosiloxane fiber (SPME/GC-MS with CAR/PDMS fiber), headspace solid-phase microextraction/gas chromatography-mass spectrometry with polyacrylate fiber (SPME/GC-MS with PA fiber), and ultra performance liquid chromatography–photodiode array detector-tandem mass spectrometry (UPLC-PDA-MS/MS). Principal Component Analysis (PCA) revealed that fingerprints obtained using all four chromatographic methods were suitable for classification using machine learning (ML). Random Forest (RF) and Support Vector Machines (SVM) yielded accuracies of at least 99% in the varietal classification of Zweigelt and Rondo wines and therefore proved suitable for robust fingerprinting-based Quality Assurance/Quality Control (QA/QC) procedures. In the case of wine classification by the type of MLF, the classifiers performed slightly worse, with the poorest accuracy of 91% for SVM and SPME/GC-MS with CAR/PDMS fiber, and no less than 93% for the other methods. Ultra-fast GC is the greenest and UPLC-PDA-MS/MS is the most practical of the four chromatographic methods.

Wild Bee Conservation in Viticulture: Effects of Semi-Natural Habitats, Organic Management, and Fungicide Reduction.

In agricultural landscapes, the removal of semi-natural habitats (SNH) and the intensive use of pesticides contribute to declines of biodiversity, including crop pollinators such as bees (Hymenoptera: Apoidea). However, effects of pesticide use and landscape characteristics on bees have rarely been studied together. In this study, we investigated how SNH in the surrounding landscape, organic and conventional management, and the reduction of fungicides affect wild bee diversity in 32 vineyards in southwest Germany. We used yellow pan traps to sample bees in a crossed design of management (organic vs. conventional) and fungicide use (reduced in fungus-resistant grape varieties vs. regular) along a gradient with increasing proportions of SNH in the surrounding landscape. Higher proportions of SNH influenced species composition of bees and increased the abundance and richness of above-ground-nesting species. Organic vineyards had a 49% higher abundance of bees compared to conventional vineyards. The reduction of fungicides did not affect bee diversity nor abundance. The absence of a response to fungicide intensity suggests that the benefit of organically managed vineyards to wild bees was through differences in their vegetation management, which is in line with the positive response of bees to SNH in the surrounding landscape. Synthesis and applications: Our study underlines that the local provision of diverse vegetation in vineyards and the landscape-scale provision of suitable SNH are key factors for wild bee conservation in viticulture.

Grape and tropical fruits wines from Cuba: characterisation and identification of novel enologic products through impact aroma compounds

ABSTRACT Cuban grape and tropical fruit wines are well recognised by consumers at international events, but research on them is still scarce and necessary to improve wine quality. The work aimed to identify the aroma profile of six Cuban wines produced from grapes (Aramon and Parra grapes), papaya (Carica papaya L.), cherry (Prunus cerasus L.), elderberry (Sambucus nigra L.), cactus fruits (Pereskia aculeate L.) and star fruit (Averrhoa carambola L.). The free and glycosidically bound volatile compositions were studied by gas chromatography-mass spectrometry (GC-MS). It was discovered, for the first time in Cuban wines produced from tropical grape varieties and fruits, the presence of alcohols, esters, acids, aldehydes, lactones, ketones, terpenes, and a variety of volatile phenols. The results obtained contribute to a better understanding of the quality of Cuban wines of locally high commercial demand.

Impact of olive oil and potassium carbonate pretreatment on physico-chemical properties of sun-dried Sundar Khani raisins (Vitis vinifera L.)

Sundar Khani is native grape variety of Pakistan which has long berry length and significantly rich in taste and sweetness. There is limited literature on pretreatment and drying data for this valuable variety of Grapes. Current study was conducted to investigate the physio-chemical indices of potassium carbonate (K2CO3) and olive oil combined treatments followed by natural sun drying method. The effects of 2 % K2CO3 pretreatments alone and in combination with various amounts of pure olive oil (1 %, 2 %, and 3 %) were studied. The results showed that, physical attributes like raisin length, width, volume, weight and total replication weight increased under distilled water treatment, while, combination of 2 % K2CO3 + 3 % Olive oil significantly reduced the drying time, 2 % K2CO3 + 1 % Olive oil gave higher final yield, rehydration ratio was highest under dH2O treatment and greater decay loss was observed at 2 %K2CO3 + 2 % olive oil. Further, 2 % K2CO3 displayed higher ratios of total soluble solids, sugars and peroxidase enzyme activity as well as titratable acidity, anthocyanins, total phenols, flavonoids were maximum at 2 % K2CO3 + 2 % Olive oil pretreatment. In addition, 2 % K2CO3 + 3 % Olive oil increased the Catalase enzyme activity as well as achieved higher scores in the evaluation of sensory attributes particularly morphological form, color and overall acceptance. This study aimed to investigate the physicochemical indices of Sundar Khani grapes under different pretreatment and sun-drying conditions using K2CO3 and olive oil and it could be suggested that raisin production of Sundar Khani by using above mentioned treatments along with sun drying could have future scope both in export and industrial markets due to its incredible reduction in drying and processing time.

Metabolome and Transcriptome Joint Analysis Reveals That Different Sucrose Levels Regulate the Production of Flavonoids and Stilbenes in Grape Callus Culture.

To reveal the effect of sucrose concentration on the production of secondary metabolites, a metabolome and transcriptome joint analysis was carried out using callus induced from grape variety Mio Red cambial meristematic cells. We identified 559 metabolites-mainly flavonoids, phenolic acids, and stilbenoids-as differential content metabolites (fold change ≥2 or ≤0.5) in at least one pairwise comparison of treatments with 7.5, 15, or 30 g/L sucrose in the growing media for 15 or 30 days (d). Resveratrol, viniferin, and amurensin contents were highest at 15 d of subculture; piceid, ampelopsin, and pterostilbene had higher contents at 30 d. A transcriptome analysis identified 1310 and 498 (at 15 d) and 1696 and 2211 (at 30 d) differentially expressed genes (DEGs; log2(fold change) ≥ 1, p < 0.05) in 7.5 vs. 15 g/L and 15 vs. 30 g/L sucrose treatments, respectively. In phenylpropane and isoflavone pathways, DEGs encoding cinnamic acid 4-hydroxylase, chalcone synthase, chalcone isomerase, and flavanone 3-hydroxylase were more highly expressed at 15 d than at 30 d, while other DEGs showed different regulation patterns corresponding to sucrose concentrations and cultivation times. For all three sucrose concentrations, the stilbene synthase (STS) gene exhibited significantly higher expression at 15 vs. 30 d, while two resveratrol O-methyltransferase (ROMT) genes related to pterostilbene synthesis showed significantly higher expression at 30 vs. 15 d. In addition, a total of 481 DEGs were annotated as transcription factors in pairwise comparisons; an integrative analysis suggested MYB59, WRKY20, and MADS8 as potential regulators responding to sucrose levels in flavonoid and stilbene biosynthesis in grape callus. Our results provide valuable information for high-efficiency production of flavonoids and stilbenes using grape callus.