Hybrid Grape Research Articles

Evaluation of Ripening Indicators for Harvest-time Decision Making in Cold Climate Grape Production

Currently, growers and winemakers of cold climate interspecific hybrid grape (CCIHG) cultivars rely solely on technological maturity variables of Brix, titratable acidity (TA), and pH as ripening indicators for harvesting and winemaking decisions. In contrast, the use of additional chemical variables to determine optimal harvest times is a common practice in most regions of the world where the European V. vinifera grape is cultivated. As there are significant differences in berry chemistry between CCIHG and V. vinifera, the objective of the present study was to evaluate, by linear regression coupled with PCA and cluster analysis, the suitability of six additional maturity variables (berry fresh weight, total protein, total phenolics, monomeric anthocyanins, percent polymeric color, and total tannins) as potential ripening indicators for the CCIHG cultivars Brianna, Frontenac, La Crescent, Leon Millot, Marechal Foch, Marquette, MN 1220, and Petite Pearl. We observed that berry fresh weight, total phenolics, and percent polymeric color had inconsistent and poorly modelable relationships from year to year and across distinct grape cluster microclimate treatments, resulting in their poor suitability as ripening indicators. In addition to the standard technological maturity variables of Brix, TA, and pH, the variables of total protein concentration for white cultivars and monomeric anthocyanin, total protein, and total tannin concentrations for red cultivars have consistent modelable linear relationships from veraison to harvest, making them good candidates for consideration for future use as ripening indicators.

Cryo-scanning electron microscopy reveals that supercooling of overwintering buds of freezing-resistant interspecific hybrid grape ‘Yamasachi’ is accompanied by partial dehydration

Dormant compound buds of grapevines adapt to subfreezing temperatures through a freezing avoidance mechanism. One still-unclear question, however, is whether supercooled water in primordial cells of dormant grape buds are partially dehydrated under subfreezing temperatures. In this study, we used differential thermal analysis (DTA) and cryo-scanning electron microscopy (cryo-SEM) to look for partial dehydration of primordial cells of the freezing-resistant interspecific hybrid cultivar ‘Yamasachi’. According to DTA, the freezing temperature of supercooled water in primary buds was not significantly affected by cooling rates between 2 and 5 °C/h; however, maintaining the bud temperature at −15 °C for 12 h followed by cooling at a rate of 5 °C/h depressed the freezing temperature. As revealed by cryo-SEM observation, many wrinkles were present on inner surfaces of walls and outer surfaces of plasma membranes of leaf primordial cells in dormant buds frozen to −15 °C. These results suggest the existence of partial dehydration in dormant-bud primordial cells under subfreezing temperatures. The apparent absence of extracellular ice crystals in bud primordial tissues under subfreezing temperatures suggests that Yamasachi dormant buds adapt to subfreezing temperatures by extraorgan freezing. When we coated primary buds with silicone oil to inhibit freeze dehydration of primordial cells, the freezing temperature of buds was slightly but significantly increased. This result suggests that the partial dehydration of cells promotes bud supercooling capability and has an important role in the freezing adaptation mechanism of grapevines.

Phenology, thermal requirements and maturation of the SR 0.501-17 white wine grape hybrid cultivated in contrasting climatic conditions

ABSTRACT The SR 0.501-17 grape hybrid developed for wine making purposes, is characterized for producing white grapes and small berries with seeds. The purpose of this study was to characterize the phenology, thermal requirements and must physicochemical characteristics of the hybrid, in contrasting climatic conditions due to altitude at Jundiai (715m) and Votuporanga (483m) respectively located at east and northwest of the Sao Paulo State-Brazil. Evaluations were performed from 2012 to 2016 and observations during the vine growth period and data of phenology and must soluble solids content and acidity measurements at harvest were taken. Average duration of the pruning-harvest period was 146 and 131 days and grape maturation period was 29 and 27 days, respectively for Jundiai and Votuporanga. Thermal requirement expressed in degree days for the hybrid growth cycle was 1663 and 1923, respectively for Jundiai and Votuporanga. Rainfall during the maturation period showed negative correlation with total soluble solids and maturation index and positive correlation with titratable acidity. The effect of temperature on vine growth cycle were more pronounced in Jundiai in comparison to Votuporanga while the effect of rainfall on the maturation characteristics were more effective in Votuporanga when compared to Jundiai.

Zinc oxide nanoparticles (ZnONPs) -induced antioxidants and photocatalytic degradation activity from hybrid grape pulp extract (HGPE)

The growing era of nanotechnology has attracted the attention of people towards the inclusion of nanoparticles in our day to day life. The conversion of copper (Cu) and silver (Ag) into nanomaterial for biomedical application has increased the urge of working with different metallic nanoparticles. Considering these facts, zinc nanoparticles (ZnO) are synthesized using biological sources like plants, fruits, bacteria, fungi, algae etc. The introduction of biological sources for the synthesis of ZnONPs will promote a safer and non-toxic approach. The biomolecules present in biological sources act as capping or coating agents to enhance the stability and potentials of the ZnONPs. In the present study aqueous extract of Vitis rotundifolia (Hybrid Grapes) pulp is used for the synthesis of ZnO nanoparticles (ZnONPs). The structural and chemical characterization of the synthesized ZnONPs was performed using various analytical. The excitation of absorption peak at 371 nm confirmed the synthesis of ZnONPs. Morphological characterization confirmed the formation of irregular hexagonal, crystalline ZnONPs with an average size of 23.56 nm. ZnONPs were further taken for determining the photocatalytic degrading potential against Malachite Green (MG) dye. After 150 min of incubation under dark condition the dye was completely degraded. The present result clearly suggest that ZnONPs synthesized using hybrid grapes pulp extract (HGPE) could be an active candidate for removing carcinogenic and toxic chemical dyes released from textile and dye industries. Further expanding the application of HGPE-ZnONPs will promote a remarkable bioremediation application against water pollution.

Exploring potentials of indigenous yeasts in fermentation of Chambourcin Grapes

Background: Indigenous yeasts present on grape berries have been shown to impact the winemaking process and final wine quality. In this study, we used Chambourcin, a hybrid grape cultivar, to isolate indigenous yeasts for potential use in winemaking. Hybrid grapes are of particularly interest due to higher resistance to cold temperature and fungal diseases. Methods: Yeasts were isolated from spontaneous fermentation of crushed grapes by plating on Dichloran Rose Bengal Chloramphenicol agar and identified by Sanger sequencing. Yeast candidates were selected for their ability to grow in Yeast Extract-Peptone-Dextrose broth supplemented with varying ethanol concentration. Candidate yeasts were chosen for mock fermentation using sterile Chambourcin juice. Volatile and non-volatile compounds that predict wine quality (flavor and aroma) were measured by UPLC and GC-MS. Results: Hanseniaspora uvarum, Starmerella bacillaris, Candida californica, and Zygoascus meyerae were predominantly isolated from Chambourcin. S. bacillaris isolate 180002 and C. californica isolate 180004 were able to tolerate up to 10% ethanol compared to S. cerevisiae (ethanol tolerance up to 12%). Our results demonstrate that isolate 180002 grown in ethanol supplemented medium is comparable to the commercial S. cerevisiae. Various aroma profiles of three main chemical families – esters, higher alcohol and volatile acids in products fermented by S. bacillaris and other isolates were observed. Conclusion: Starmerella bacillaris isolate 180002 demonstrates potential for use in winemaking with hybrid grapes based on ethanol tolerance and production of wine related chemical compounds. This study further supports the application of indigenous grape-associated yeasts in creating flavor and aroma diversity of wine.

North American Grape 'Norton' is Resistant to Grapevine Vein Clearing Virus.

Grapevines (Vitis spp.) host viruses belonging to 17 families. Virus-associated diseases are a constant challenge to grape production. Genetic resources for breeding virus-resistant grape cultivars are scarce. 'Norton' is a hybrid grape of North American Vitis aestivalis and is resistant to powdery mildew and downy mildew. In this study, we assessed resistance of 'Norton' to grapevine vein clearing virus (GVCV), which is prevalent in native, wild Vitaceae and in vineyards in the Midwest region of the U.S. We did not detect GVCV in 'Norton' as either the scion or the rootstock up to 3 years after it was grafted with a GVCV-infected 'Chardonel' grapevine. Upon sequencing of small RNAs, we were able to assemble the GVCV genome from virus small RNAs in GVCV-infected 'Chardonel' scion or rootstock, but not from grafted 'Norton' scion and rootstock. This study unveils a new trait of 'Norton' that can be used in breeding GVCV-resistant grape cultivars, and to investigate genetic mechanisms of 'Norton' resistance to GVCV.

Effect of Vintage and Viticultural Practices on the Phenolic Content of Hybrid Winegrapes in Very Cool Climate

Vine growing and wine production is gaining in popularity around the Baltic Sea Region. The first aim of the experiment was to determine the variability of the total phenolic and anthocyanin content (from 2010 to 2018) and of individual anthocyanin content (from 2016 to 2018) in the hybrid grape cultivars ‘Hasansky Sladky’, ‘Zilga’, and ‘Rondo’. In field conditions ‘Rondo’ had winter cold damage to canes in two years. Therefore, the second aim was to determine the effect of high polyethylene tunnel and field conditions on fruit total and individual anthocyanin content of ‘Rondo’ from 2016 to 2018. Over nine years, the total phenolic content ranged from 192 to 671 mg 100 g−1 and anthocyanins from 30 to 405 mg 100 g−1 spectrophotometrically. The anthocyanin (delphinidin-3-O-glucoside, cyanidin-3-O-glucoside, petunidin-3-O-glucoside, peonidin-3-O-glucoside, malvidin-3-O-glucoside) content depended on cultivar properties and climatic parameters. Antioxidant activity was cultivar dependent and ranged from 40 to 88%. Polytunnel cultivation increased the content of total anthocyanins in ‘Rondo’ from 447 to 1472 mg 100 g−1 (by chromatographically) in cooler year, but in warmer years it decreased from 3645 to 1618 mg 100 g−1. Individual anthocyanins showed the same tendency. Grapevine cultivar ‘Rondo’ is recommended for tunnel growing in very cool climate conditions.

Chemistry and Reactivity of Tannins in Vitis spp.: A Review.

Tannins are a group of polyphenols found in fruits, leaves, trees, etc., well known in the leather industry and in apples, persimmons and grapes, because of their capacity to interact with other polyphenols or other components either from the food product or from saliva. Prior to being able to interact with other compounds, tannins have to be extracted from the food matrix, which depends on their chemistry, as well as the chemical structure of other components, such as cell wall material and proteins. Vitis vinifera grapes are commonly grown around the world and are used in winemaking, providing good quality wines with different levels of tannins responsible for the final wine’s astringency. Many studies have focused on tannins extractability and retention with cell wall material, and the reactivity of tannins with proteins in Vitis vinifera grapes and wine, but there are very few reports for other Vitis species. However, depending on the environmental characteristics of certain regions, Vitis hybrid grapes are grown and used to produce wines more and more. This review focuses on the comparison of the chemistry of tannins, and their reactivity with other macromolecules in Vitis species.

Biogenic Amines and the Antioxidant Capacity of Juice and Wine from Brazilian Hybrid Grapevines.

Some biogenic amines (BAs) are used as quality markers in grape-derived products. The prolife of 9 BAs was determined in juices and wines elaborated from hybrid grapes. Low levels of histamine, tyramine and cadaverine were found. Juices elaborated from 'BRS Rúbea' showed the highest tyramine levels (1.56mg/L), while no histamine was found in wines elaborated from 'Seleção 34' and its higher content was detected in 'BRS Carmem' (3.55mg/L). Juices elaborated from 'BRS Violeta' showed elevated content (472.88mg/L) of total phenolic compounds (TPC) and mono-hydrated serotonin (6.20mg/L), and wines elaborated from 'Violeta' presented a high serotonin mono-hydrate content (23.63mg/L) and high antioxidant activity with FRAP test (77.24mmol FeSO4/L). Juices elaborated from hybrid grapes 'BRS Violeta' and wines from 'BRS Violeta', 'Seleção 34' and 'Seleção 13' had high levels of bioactive compounds, emphasizing the great potential of these cultivars for winemaking.

Thiol precursors in Vitis mould-tolerant hybrid varieties.

Over recent years, a new wave of disease-tolerant to mildew varieties has flooded the viticulture sector, for reasons of human safety and economic expediency. These hybrid grape cultivars are selected mainly on the basis of their intrinsic capability to counter the attack of the main fungal diseases that affect grape production, such as downy mildew and powdery mildew. However, their organoleptic and oenological characteristics have not yet been studied in depth for purposes of both juice and wine production, due to the high number of newly proposed germplasms and the lack of information about their adaptability to different environments. This work examines the thiol aroma precursors concentration in 64 red and white disease-tolerant hybrid varieties in the vine germplasm collections of Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria-Viticulture and Enology Research Center and Fondazione Edmund Mach, both from the north-east of Italy. All cultivars showed the presence of 3-mercaptohexan-1-ol (3MH) precursors, ranging from 4.4 to 1141 μg kg-1 for 3-S-glutathionyl hexan-1-ol (GSH-3MH), and from 0.3 to 136 μg kg-1 for 3-S-cysteinyl 3-hexan-1-ol. The concentration of GSH-3MH exceeded 600 μg kg-1 in eight varieties, with values comparable to those of the richest Vitis vinifera reported so far. On average, red grapes showed higher concentrations of 3MH precursors than white ones did. Only two hybrids had 4-mercapto-4-methylpentan-2-one (4MMP) precursors over the limit of quantification, albeit with a much higher concentration than those normally reported in Sauvignon Blanc. This is the first detailed survey of 3MH and 4MMP precursors carried out taking into account a considerable number of hybrid grape varieties. The results show that some of these varieties could be interesting for the production of tropical juices or tropical-aromatic wines and soft drinks, through the enzymatic liberation of thiol aromas, as well as for the production of aromatizing tannins to be used in the food industry. © 2020 Society of Chemical Industry.

Simple DNA marker system reveals genetic diversity of MYB genotypes that determine skin color in grape genetic resources

Grape skin color is determined mainly by the quantity and composition of anthocyanins, and the MYB genotype at the color locus on chromosome 2 is the major genetic determinant of anthocyanin biosynthesis. Recently, poor coloration of grape berry skin has become a common problem caused mainly by high temperatures during maturation. In the present study, we developed a simple DNA marker system for predicting the MYB genotype at the color locus. Our sample preparation method for PCR and efficient DNA markers can distinguish many MYB genotypes derived from V. vinifera and interspecific hybrid grapes simultaneously. Furthermore, we constructed a database of the relationship between MYB genotype at the color locus and the “Skin color”, “Species”, “Region of origin”, and “Utilization” categories in more than 700 grape genetic resources. We found a significant association between MYB genotypes and each of the four categories. This novel DNA marker system and the database of MYB genotypes will contribute to the development of new grape varieties with well-pigmented berries despite global atmospheric warming. This study may also contribute to elucidation of the evolutionary differentiation of MYB genotypes at the color locus in Vitis species.

Knockout of VvCCD8 gene in grapevine affects shoot branching

BackgroundShoot branching is an important trait of plants that allows them to adapt to environment changes. Strigolactones (SLs) are newly identified plant hormones that inhibit shoot branching in plants. The SL biosynthesis genes CCD7 (carotenoid cleavage dioxygenase 7) and CCD8 have been found to regulate branching in several herbaceous plants by taking advantage of their loss-of-function mutants. However, the role for CCD7 and CCD8 in shoot branching control in grapevine is still unknown due to the lack of corresponding mutants.ResultsHere we employed the CRISPR/Cas9 system to edit the VvCCD7 and VvCCD8 genes in the grape hybrid 41B. The 41B embryogenic cells can easily be transformed and used for regeneration of the corresponding transformed plants. Sequencing analysis revealed that gene editing has been used successfully to target both VvCCD genes in 41B embryogenic cells. After regeneration, six 41B plantlets were identified as transgenic plants carrying the CCD8-sgRNA expression cassette. Among these, four plants showed mutation in the target region and were selected as ccd8 mutants. These ccd8 mutants showed increased shoot branching compared to the corresponding wild-type plants. In addition, no off-target mutation was detected in the tested mutants at predicted off-target sites.ConclusionsOur results underline the key role of VvCCD8 in the control of grapevine shoot branching.

Створення садів горіха волоського (Juglans regia L.) шляхом ущільнення плодоносних виноградних насаджень

The profound analysis of the walnut cultivation current state in the world and role of Ukraine in this process is made by the authors V. Kostenko and N. Kiktenko in the paper. The substantiation has been presented of the necessity and opportunities for the areas and gross productions of nuts increasing in Ukraine. That is accounted for by the high profitability level of its production and export potential in the products sales. The cost estimate for creating young walnut stands is demonstrated as well as of managing them. The technology of growing grape hybrid Isabella is described. Weighty argument of lack of prospects end economic inexpediency of its cultivation in Moldova and Ukraine are presented as well as the of cost estimate of planting establishment and growing one hectare of walnut. The natural and climatic zone of the enterprise establishment is described, on the basis of which a production experiment was conducted. This is described in details. The number of treatments against diseases and pests is given. The results are presented of accounting for the yield and income from the vineyard for the period of the researches. The planting plan of the experimental orchard, a hole, scale of fertilizing during planting are described, as well as technological peculiarities of the walnut trees formation in the row of fruiting vineyards. The walnut planting tock assortment is indicated. The results are presented of accounting for the nuts yield by years and cultivars. The authors also described the mycorhiza effects on the development of walnut planting trees and vine bushes. Moreover, the summaries are provided of the videos that were periodically posted on the Internet during the experiment. The recommendations to the producers are also presented.

Results of research into affinity of promising table grape hybrid forms

Aim. To study affinity of 12 rootstock-scion combinations of new promising table grape hybrid forms with common and new Ukrainian rootstock varieties. Results and Discussion. The study results demonstrated differences between rootstock-scion combinations in the number of check seedlings after stratification and differences in survival rates of seedlings after their planting. Analysis of phenological data showed significant differences in “the vegetation period length” and “the sum of active temperatures” for all hybrid forms grafted onto Dobrynia variety. Analysis of data on promising hybrid forms in rootstock-scion combinations allowed us to confirm significant effects of rootstocks on scion varieties, which cover both bio-physiological and economic characteristics of a grafted organism. Conclusions. Estimated amounts of check grafted seedlings after stratification in all 12 variants of rootstock-scion combinations were quite high (57-92%). Survival rates of seedlings after their planting ranged from 57% to 100%. For traditional wine-growing regions, it is recommended to graft Tairian and Persei hybrid forms onto Dobrynia and Berlandieri x Riparia Kober 5BB rootstocks. Fontan hybrid form should be grafted onto Riparia x Rupestris 101-14 (reference cultivar) and Dobrynia varieties. For experimental, non-traditional regions of viticulture, it should be taken into account that vegetation period of seedlings grafted onto Dobrynia variety tends to increase by three days for Persei and Fontan hybrid forms (2%). The vegetation period of Tairian – Dobrynia rootstock-scion combination exceeded reference combination rates by seven days (5.7%). Studies of the influence of stress factors on traits of interest will be continued.

Phenology and Winter Hardiness of Cold-climate Grape Cultivars and Advanced Selections in Iowa Climate

The popularity of grape (Vitis sp.) and wine production in the upper midwest region of the United States is increasing steadily. The development of several cold-climate, interspecific-hybrid grape cultivars (northern hybrids) since the 1980s has improved the probability of success for both new and established vineyards in this area of the country, but long-term data describing the performance of these cultivars in midwestern U.S. climates are needed to both aid growers in their choice of cultivars and to provide them with information about factors important in their management. We characterized the long-term winterhardiness and annual phenology of 12 cold-climate northern hybrid grape cultivars (two established cultivars, five newer cultivars, and five advanced selections) grown in a randomized and replicated field plot in central Iowa, an area that offers a warm growing season and very cold dormant season for grape culture. The established cultivars included in the study were Frontenac and St. Croix. The newer cultivars evaluated were Arandell, Corot noir, La Crescent, Marquette, and Petit Ami, and the advanced selections were MN 1189, MN 1200, MN 1220, MN 1235, and MN 1258. The grape trial was established in 2008, and vines were evaluated from 2011 through 2017 for annual timing of budbreak, bloom, veraison, and harvest, as well as winter survival of vines and primary buds. As a group, the northern hybrids in our trial showed good winterhardiness of vines but variable hardiness of primary buds across the six winters, which ranged from warmer than average to much colder than average. In Iowa climate, buds of northern hybrids were generally most vulnerable to cold temperature damage from late-winter (March) low-temperature events or from extreme midwinter low-temperature events. The bud hardiness of individual cultivars ranged from very hardy (Frontenac, Marquette, and MN 1235) to poor hardiness (Arandell, Corot noir, Petit Ami, and MN 1189), with all 12 cultivars showing good bud survival during Iowa winters that were warmer than average, but the less-hardy cultivars showing poor bud survival during winters that were colder than average. Evaluations of phenology revealed that heat accumulation measured in growing degree days with a threshold of 50 °F was not a reliable index for predicting the timing of annual developmental stages for the cultivars we tested. Our results indicate that northern hybrids rely on other factors in addition to heat accumulation for guiding annual development, and that factors such as photoperiod likely have a strong influence on phenological timing during seasons with unusual weather patterns. We determined that none of the cultivars were vulnerable to cold temperature damage to fruit before harvest in Iowa’s climate, but that three of the cultivars (Arandell, Marquette, and MN 1235) were highly vulnerable to shoot damage from spring freeze events, and four others (Corot noir, La Crescent, MN 1200, and MN 1220) were moderately vulnerable to cold damage to shoots in spring. An itemized summary of the relative hardiness, vulnerabilities, and timing of phenological stages of the 12 cultivars is provided to aid growers in selection and management of grape cultivars for Iowa climate. Based on hardiness and phenology, four of these cultivars (Frontenac, MN 1258, MN 1220, and MN 1200) have the lowest risk of issues related to cold temperatures.

Disease Resistant Bouquet Vine Varieties: Assessment of the Phenolic, Aromatic, and Sensory Potential of Their Wines.

The search for grape varieties resistant to diseases and to climatic changes notably concerns the wine industry. Nine monovarietal wines from new red grape varieties resistant to cryptogamic diseases (downy and powdery mildews) were evaluated in terms of their total phenolic, anthocyanin and proanthocyanidin contents, anthocyanin profile, volatile composition, and sensory attributes. Thus, the question remains, will these hybrid grapes (≥97.5% of Vitis vinifera genome) lead to wines with organoleptic properties similar to those of Vitis vinifera wines that consumers are used to? Total phenolic (1547–3418 mg GA/L), anthocyanin (186–561 mg malvidin/L), and proanthocyanidin (1.4–4.5 g tannins/L) contents were in broad agreement with those previously described in the literature for monovarietal wines produced with well-known red grape varieties (Cabernet Sauvignon, Merlot, Syrah). With regard to fruity aroma, ethyl esters of straight-chain fatty acids (530–929 μg/L) stood out clearly as the major volatile components for all hybrid wines considered. Sensory analysis revealed significant differences (p < 0.05) for visual aspect, aroma, flavor, global balance, astringency, and body. Overall, these new hybrid grape varieties are not only resistant to cryptogamic diseases, but also present enough potential to become quality wines, since their phenolic and volatile attributes are close to those of common red monovarietal wines.

The grapevine homeobox gene VvHB58 influences seed and fruit development through multiple hormonal signaling pathways

BackgroundThe homeobox transcription factor has a diversity of functions during plant growth and development process. Previous transcriptome analyses of seed development in grape hybrids suggested that specific homeodomain transcription factors are involved in seed development in seedless cultivars. However, the molecular mechanism of homeobox gene regulating seed development in grape is rarely reported.ResultsHere, we report that the grapevine VvHB58 gene, encoding a homeodomain-leucine zipper (HD-Zip I) transcription factor, participates in regulating fruit size and seed number. The VvHB58 gene was differentially expressed during seed development between seedless and seeded cultivars. Subcellular localization assays revealed that the VvHB58 protein was located in the nucleus. Transgenic expression of VvHB58 in tomato led to loss of apical dominance, a reduction in fruit pericarp expansion, reduced fruit size and seed number, and larger endosperm cells. Analysis of the cytosine methylation levels within the VvHB58 promoter indicated that the differential expression during seed development between seedless and seeded grapes may be caused by different transcriptional regulatory mechanisms rather than promoter DNA methylation. Measurements of five classic endogenous hormones and expression analysis of hormone-related genes between VvHB58 transgenic and nontransgenic control plants showed that expression of VvHB58 resulted in significant changes in auxin, gibberellin and ethylene signaling pathways. Additionally, several DNA methylation-related genes were expressed differentially during seed development stages in seedless and seeded grapes, suggesting changes in methylation levels during seed development may be associated with seed abortion.ConclusionVvHB58 has a potential function in regulating fruit and seed development by impacting multiple hormonal pathways. These results expand understanding of homeodomain transcription factors and potential regulatory mechanism of seed development in grapevine, and provided insights into molecular breeding for grapes.

Polyphenolic Profiling, Browning, and Glutathione Content of Sparkling Wines Produced with Nontraditional Grape Varieties: Indicator of Quality During the Biological Aging.

Sparkling wines were elaborated with the nontraditional varieties Villenave, Niagara, Manzoni, and Goethe, and monitored in relation to the changes in phenolic composition, browning index, and glutathione content during 18 months of biological aging (sur lies). Important changes in the phenolic profile, browning index, and glutathione content were observed in the sparkling wines during the over-lees aging period. The major phenolic compound in the sparkling wines was tyrosol, followed by caffeic, trans-caftaric, and gallic acids, catechin and epicatechin. The biological aging led to an increase in the individual phenolic compounds, especially caffeic, gallic, and ellagic acids, and an increase in the browning index was also observed during the aging period. Caffeic acid was significantly correlated with browning and aging period in all sparkling wines, which indicates that this compound can be useful as a quality marker to monitoring the biological aging profile of white sparkling wines. The results obtained indicate that the aging period (sur lie) had an important influence on the changes in the unique phenolic profile of the sparkling wines elaborated with nontraditional varieties. PRACTICAL APPLICATION: In sparkling wines production, the secondary fermentation occurring in the sealed bottle during the vinification contributes greatly to their quality and sensory complexity. The Vitis labrusca and hybrid grapes varieties represent most of the grapes cultivated in Brazil being employed in the elaboration of juices and wines. These varieties present a great oenological potential and have not been explored yet regarding to the production of white sparkling wines. The use of these nontraditional grape varieties cultivated in South Brazil may be a viable alternative in the production of white sparkling wines with biological aging potential and particular bioactive properties.

Comparative assessment of amino acids and volatile compounds role in the formation of wines sensor properties by means of covariation analysis

The objects of study were 150 samples of natural dry red and white grape wines of Russian origin, obtained by traditional technologies from European and hybrid grape varieties grown in wineries in Krasnodar Krai in 2010–2016. Natural red (Cabernet, Merlot) and white (Aligote, Riesling, Pinot Noir) (alcohol content of 9–13 % by volume, acidity of 4–7 g/dm3), as well as blend wines based on Cabernet Sauvignon, Merlot and Pinot Noir wines made under experimental conditions were analyzed. Chromatographic and electrophoretic methods were used to determine the content of volatile components and amino acids in the studied samples. A sensory assessment of wine quality was carried out by wine specialists working in the wine industry and having professional experience in the field of sensory analysis. Using statistical modeling we carried out a comparative assessment of the role of amino acids - threonine, proline, arginine and volatile compounds - methanol, acetic acid, furfural in the perception of taste and aromatic properties of wines, a general indicator of which is the average tasting rating. High adequacy of the regression model constructed using covariance analysis indicates that mainly amino acids and volatile compounds determine the sensory properties of wines. The dominant role of amino acids in the perception of taste and aromatic characteristics compared to other wine components is mathematically justified in accordance with the criterion of one-dimensional significance. It has been shown that more than 82% of the sensory characteristics of the analyzed wines group fall on the amino acids and volatile compounds under consideration, and less than 18% - on all the others, including titrated acids, free amino acids, mineral components, phenols, etc.

Nonlinear Behavior of Protein and Tannin in Wine Produced by Cofermentation of an Interspecific Hybrid (Vitis spp.) and vinifera Cultivar

Wines produced from red interspecific hybrid grape cultivars (Vitis spp.) typically have lower tannin concentrations than wines produced from vinifera cultivars, which can be attributed to the lower concentration of tannins and higher concentration of tannin-binding proteins of interspecific cultivars. Tannin in wines produced from hybrid cultivars may be increased by blending hybrids with vinifera. We hypothesized that blending of grapes prior to fermentation (cofermentation) would result in final wine tannin concentrations lower than those predicted from the individual components due to protein-tannin binding, but that this effect would be absent from monovarietal wines blended postfermentation. To evaluate this hypothesis, a high tannin V. vinifera cultivar (Cabernet Sauvignon) was blended with an interspecific hybrid (Marquette) at different ratios either before (cofermentation) or after fermentation over a two-year period. The tannin and protein concentrations of the wines were measured by methyl cellulose precipitation assay and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, respectively. Tannin and protein concentrations in blended wines were compared to values predicted from the linear combination of the two monovarietal wines. Cofermented blends with a high proportion of Marquette had up to 25% lower tannin than predicted, but observed and predicted tannin concentrations did not differ for most cofermentations and postfermentation blends. However, protein concentrations for many of the blends—especially from cofermentation—were lower than predicted values (>50% in some cases). Loss of protein due to adsorption to tannin was well modeled by a Freundlich adsorption isotherm.