Grapevine Varieties Research Articles

Grapevine Leafroll-Associated Virus 3 in Single and Mixed Infections Triggers Changes in the Oxidative Balance of Four Grapevine Varieties.

With the aim to characterize changes caused by grapevine leafroll-associated virus 3 (GLRaV-3) singly or in coinfection with other viruses and to potentially determine genotype-specific or common markers of viral infection, thirty-six parameters, including nutrient status, oxidative stress parameters, and primary metabolism as well as symptoms incidence were investigated in 'Cabernet Franc,' 'Merlot,' 'Pinot Noir,' and 'Tribidrag' grapevine varieties. Host responses were characterized by changes in cellular redox state rather than disturbances in nutrient status and primary metabolic processes. Superoxide dismutase, hydrogen peroxide, and proteins were drastically affected regardless of the type of isolate, the host, and the duration of the infection, so they present cellular markers of viral infection. No clear biological pattern could be ascertained for each of the GLRaV-3 genotypes. There is a need to provide a greater understanding of virus epidemiology in viticulture due to the increasing natural disasters and climate change to provide for global food production security. Finding grape varieties that will be able to cope with those changes can aid in this task. Among the studied grapevine varieties, autochthonous 'Tribidrag' seems to be more tolerant to symptoms development despite numerous physiological changes caused by viruses.

Global predictions for the risk of establishment of Pierce’s disease of grapevines

The vector-borne bacterium Xylella fastidiosa is responsible for Pierce’s disease (PD), a lethal grapevine disease that originated in the Americas. The international plant trade is expanding the geographic range of this pathogen, posing a new threat to viticulture worldwide. To assess the potential incidence of PD, we have built a dynamic epidemiological model based on the response of 36 grapevine varieties to the pathogen in inoculation assays and on the vectors’ distribution when this information is available. Key temperature-driven epidemiological processes, such as PD symptom development and recovery, are mechanistically modelled. Integrating into the model high-resolution spatiotemporal climatic data from 1981 onward and different infectivity (R0) scenarios, we show how the main wine-producing areas thrive mostly in non-risk, transient, or epidemic-risk zones with potentially low growth rates in PD incidence. Epidemic-risk zones with moderate to high growth rates are currently marginal outside the US. However, a global expansion of epidemic-risk zones coupled with small increments in the disease growth rate is projected for 2050. Our study globally downscales the risk of PD establishment while highlighting the importance of considering climate variability, vector distribution, and an invasive criterion as factors to obtain better PD risk maps.

Non-Anthocyanin Compounds in Minority Red Grapevine Varieties Traditionally Cultivated in Galicia (Northwest Iberian Peninsula), Analysis of Flavanols, Flavonols, and Phenolic Acids

Non-anthocyanin compounds (NAN) such as flavonol, flavanol, and phenolic acids should be considered in the characterization of minority red grapevine varieties because these compounds are involved in copigmentation reactions and are potent antioxidants. Sixteen NAN were extracted, identified, and quantified by High Performance Liquid Chromatography (HPLC) from grapes of 28 red genotypes of Vitis vinifera L. grown in Galicia (Northwest of Spain) in 2018 and 2019 vintages. The percentage of total NAN with respect to the total polyphenol content (TPC) values was calculated for each sample and established into three categories: high percentage NAN varieties (NANV), those varieties showing low percentages of NAN (ANV), and finally those varieties showing medium percentages of NAN (NANAV). 'Xafardán' and 'Zamarrica', classified as NANAV, had high values of TPC and showed good percentages of flavonol and flavanol compounds. Principal component analyses (PCA) were performed with flavonol, flavanol, and phenolic acid profiles. The flavonol and flavanol profiles allowed a good discrimination of samples by variety and year, respectively. The flavonol profile should therefore be considered as a potential varietal marker. The results could help in the selection of varieties to be disseminated and in the identification of the most appropriate agronomic and oenological techniques that should be performed on them.

THE BEHAVIOR OF SOME VINE VARIETIES WITH WHITE GRAPES IN THE AMPELOGRAPHIC COLLECTION OF SCDCPN DĂBULENI

The research followed the behaviour of white grape vine varieties in the ampelographic collection over a ten-year period (2012-2021). The fertility of the shoots, recorded different values depending on the variety and climatic conditions. The relative fertility coefficient recorded both subunit and superunit values depending on the year, with one exception, the variety Fetească regală Cl. 21 Bl., where the values were only superunitary (1.13-1.67), while the maximum value of the absolute fertility coefficient was recorded for the variety Blasius, ranging from 1.23 to 2.10. In terms of average grape production, for the period 2013-2021, the varieties Brumariu stood out with a production value of 15828 kg/ha and Selena with 13729 kg/ha. At the opposite end of the scale were Columna (8095 kg/ha) and Donaris (7764 kg/ha). Total sugar content values at harvest maturity varied from variety to variety and from year to year. In this respect, the Selena variety came first, with an average total sugar content of 210 g/l. Columna had the lowest average total sugar content (167 g/l).

The root transcriptome dynamics reveals new valuable insights in the salt-resilience mechanism of wild grapevine (Vitis vinifera subsp. sylvestris).

Most of elite cultivated grapevine varieties (Vitis vinifera L.), conventionally grafted on rootstocks, are becoming more and more affected by climate changes, such as increase of salinity. Therefore, we revisited the valuable genetic resources of wild grapevines (V. sylvestris) to elaborate strategies for a sustainable viticulture. Here, we compared physiological and biochemical responses of two salt-tolerant species: a wild grapevine genotype "Tebaba" from our previous studies and the conventional rootstock "1103 Paulsen". Interestingly, our physio-biochemical results showed that under 150mM NaCl, "Tebaba" maintains higher leaf osmotic potential, lower Na+/K+ ratio and a significant peaked increase of polyphenol content at the first 8h of salinity stress. This behavior allowed to hypothesis a drastic repatterning of metabolism in "Tebaba's" roots following a biphasic response. In order to deepen our understanding on the "Tebaba" salt tolerance mechanism, we investigated a time-dependent transcriptomic analysis covering three sampling times, 8h, 24h and 48h. The dynamic analysis indicated that "Tebaba" root cells detect and respond on a large scale within 8h to an accumulation of ROS by enhancing a translational reprogramming process and inducing the transcripts of glycolytic metabolism and flavonoids biosynthesis as a predominate non-enzymatic scavenging process. Afterwards, there is a transition to a largely gluconeogenic stage followed by a combined response mechanism based on cell wall remodeling and lignin biosynthesis with an efficient osmoregulation between 24 and 48 h. This investigation explored for the first time in depth the established cross-talk between the physiological, biochemical and transcriptional regulators contributing to propose a hypothetical model of the dynamic salt mechanism tolerance of wild grapevines. In summary, these findings allowed further understanding of the genetic regulation mechanism of salt-tolerance in V. sylvestris and identified specific candidate genes valuable for appropriate breeding strategies.

Weather potential for high-quality still wine from Chardonnay viticulture in different regions of the UK with climate change

UK viticulture is benefitting from climate change with an increase in vineyard area and a move towards French grapevine varieties, primarily Chardonnay and Pinot noir, to produce sparkling wine. Doubt remains, however, as to how good UK still wine can be from these varieties. The simple Chablis vintage model uses only three climatic indices: mean temperature from April to September, mean minimum temperature in September (cool night index) and total rainfall from June to September. It was applied to the UK for the periods 1981–2000, 2010–2019 and, with climate change projections, to 2040–2059 to locate sites in the UK with the climate potential to produce high-quality Chardonnay still wine. Weather data for 1981–2000 and 2010–2019 were taken from the Met Office’s HadUK-Grid at a resolution of 5 × 5 km, and climate projections for 2040–2059 were derived from UKCP18, using intermediate emission scenario RCP 4.5 at the 5th, 50th and 95th percentile probabilities. Recent and current climatic conditions throughout most of the UK were unsuitable for sustainable production of high-quality still Chardonnay wine (only 0.2 to 1.8 % of UK land area suitable), but model scores corresponded with high-quality Chardonnay still wine production observed in some regions of England in 2018. Under the 5th percentile RCP 4.5 projection for 2040–2059, climatic conditions are similar to 2010–2019 and generally unsuitable for sustainable, high-quality still Chardonnay wine production. Under the median and 95th percentile projections for 2040–2059, however, South East England and East of England have the potential for high-quality still Chardonnay wine production in an average year, and Central England also with the 95th percentile projection. Overall, climate change is expected to benefit the production of high-quality still Chardonnay wine in the medium term, with up to 42.4 % of UK land possibly climatically (but not necessarily agronomically) suitable by mid-century. The model does not account for extreme events, however, and there is uncertainty over future inter-annual weather variability, and so the sustainability of high-quality still wine production. Planting Chardonnay clones suitable for both sparkling and still wines in the most-suitable areas of England would provide flexibility and so resilience.

Regeneration of non-chimeric plants from DNA-free edited grapevine protoplasts.

The application of New Breeding Techniques (NBTs) in Vitis vinifera is highly desirable to introduce valuable traits while preserving the genotype of the elite cultivars. However, a broad application of NBTs through standard DNA-based transformation is poorly accepted by public opinion and law regulations in Europe and other countries due to the stable integration of exogenous DNA, which leads to transgenic plants possibly affected by chimerism. A single-cell based approach, coupled with a DNA-free transfection of the CRISPR/Cas editing machinery, constitutes a powerful tool to overcome these problems and maintain the original genetic make-up in the whole organism. We here describe a successful single-cell based, DNA-free methodology to obtain edited grapevine plants, regenerated from protoplasts isolated from embryogenic callus of two table grapevine varieties (V. vinifera cv. Crimson seedless and Sugraone). The regenerated, non-chimeric plants were edited on the downy- and powdery-mildew susceptibility genes, VviDMR6 and VviMlo6 respectively, either as single or double mutants.

Dissection of the Pearl of Csaba pedigree identifies key genomic segments related to early ripening in grape.

Pearl of Csaba (PC) is a valuable backbone parent for early-ripening grapevine (Vitis vinifera) breeding, from which many excellent early ripening varieties have been bred. However, the genetic basis of the stable inheritance of its early ripening trait remains largely unknown. Here, the pedigree, consisting of 40 varieties derived from PC, was re-sequenced for an average depth of ∼30×. Combined with the resequencing data of 24 other late-ripening varieties, 5,795,881 high-quality single nucleotide polymorphisms (SNPs) were identified following a strict filtering pipeline. The population genetic analysis showed that these varieties could be distinguished clearly, and the pedigree was characterized by lower nucleotide diversity and stronger linkage disequilibrium than the non-pedigree varieties. The conserved haplotypes (CHs) transmitted in the pedigree were obtained via identity-by-descent analysis. Subsequently, the key genomic segments were identified based on the combination analysis of haplotypes, selective signatures, known ripening-related quantitative trait loci (QTLs), and transcriptomic data. The results demonstrated that varieties with a superior haplotype, H1, significantly (one-way ANOVA, P < 0.001) exhibited early grapevine berry development. Further analyses indicated that H1 encompassed VIT_16s0039g00720 encoding a folate/biopterin transporter protein (VvFBT) with a missense mutation. VvFBT was specifically and highly expressed during grapevine berry development, particularly at veraison. Exogenous folate treatment advanced the veraison of "Kyoho". This work uncovered core haplotypes and genomic segments related to the early ripening trait of PC and provided an important reference for the molecular breeding of early-ripening grapevine varieties.

Grapevine Leafroll-Associated Virus 3 Replication in Grapevine Hosts Changes through the Dormancy Stage

Grapevine leafroll-associated virus 3 (GLRaV-3) is a graft-transmissible virus present in every viticultural region of the world and poses a large threat to grapevine production. Frequent coinfections with other viruses, the large number of grapevine varieties, the complexity of processes involved in plant response to virus infection, and the lack of studies on GLRaV-3 replication limit our knowledge of GLRaV-3 damaging effects and their background. In this study, five different inocula, one containing GLRaV-3 and others containing GLRaV-3 in combination with different grapevine viruses were green grafted to 52 different grapevine plants of four varieties to analyze the influence of the phenological stage and virus composition on GLRaV-3 replication. Relative concentration analysis by quantitative PCR conducted over a 16-month period revealed that other viruses as well as plant stage had a significant effect on GLRaV-3 replication and symptoms expression. The replication was most pronounced in the deep dormancy stage at the beginning of the infection, and the least at the exit of the dormancy stage. This study brings new insight into GLRaV-3 replication and discusses about viral interactions in one of the most economically important perennial plants, the grapevine.

CHARACTERIZATION THE INFLUENCE OF THE ROOTSTOCKS SO4, 44-53M, 110R AND FERCAL ON THE VOLATILE COMPOSITION OF RED WINES FROM THE HYBRID VARIETIES STORGOZIA (THREE HARVESTS) AND RUBIN (TWO HARVESTS) IN THE CONDITIONS OF CENTRAL NORTHERN BULGARIA

A gas chromatographic (GC-FID) study to characterize the influence of SO4, 44-53M, 110R and Fercal rootstocks on the volatile composition of red wines from the hybrid varieties Storgozia (harvests: 2017, 2018 and 2019) and Rubin (harvests: 2017 and 2019) under the soil and climatic conditions of Central Northern Bulgaria was conducted. The 110R rootstock in Storgozia has been shown to generate the highest total volatile content (756.10 mg/dm3) in 2017 harvest. 110R also affected the higher alcohols content of Storgozia. It generated the highest content of this indicator (713.00 mg/dm3) again in wines from the 2017 harvest. Regarding the content of esters, aldehydes and terpenes no significant differences were observed between the experimental variants of wines from this grapevine variety. In the case of Rubin wines, a very high final total volatile content was proved at rootstock 44-53M (1717.24 mg/dm3), harvest 2019. The highest concentration of higher alcohols in the 2017 harvest was identified for SO4, while in Rubin - the 2019 harvest, 110R generated the highest presence of higher alcohols. This fraction in both harvests was mainly represented by 2-methyl-1-butanol and 3-methyl-1-butanol. The esters were dominated by ethyl acetate and propyl acetate. In both harvests, the highest total terpene content was found in the wines from SO4 rootstock. The conducted research was evidence of the significant influence of different rootstocks on the volatile composition of wines from hybrid grapevine varieties in the conditions of Central Northern Bulgaria.

Fungal Metabarcoding Data for Two Grapevine Varieties (Regent and Vitis vinifera ‘Cabernet-Sauvignon’) Inoculated with Powdery Mildew (Erysiphe necator) Under Drought Conditions

Fungal Metabarcoding Data for Two Grapevine Varieties (Regent and <i>Vitis vinifera</i> ‘Cabernet-Sauvignon’) Inoculated with Powdery Mildew (<i>Erysiphe necator</i>) Under Drought Conditions

Non-linear loss of suitable wine regions over Europe in response to increasing global warming.

Evaluating the potential climatic suitability for premium wine production is crucial for adaptation planning in Europe. While new wine regions may emerge out of the traditional boundaries, most of the present-day renowned winemaking regions may be threatened by climate change. Here, we analyse the future evolution of the geography of wine production over Europe, through the definition of a novel climatic suitability indicator, which is calculated over the projected grapevine phenological phases to account for their possible contractions under global warming. Our approach consists in coupling six different de-biased downscaled climate projections under two different scenarios of global warming with four phenological models for different grapevine varieties. The resulting suitability indicator is based on fuzzy logic and is calculated over three main components measuring (i) the timing of the fruit physiological maturity, (ii) the risk of water stress and (iii) the risk of pests and diseases. The results demonstrate that the level of global warming largely determines the distribution of future wine regions. For a global temperature increase limited to 2°C above the pre-industrial level, the suitable areas over the traditional regions are reduced by about 4%/°C rise, while for higher levels of global warming, the rate of this loss increases up to 17%/°C. This is compensated by a gradual emergence of new wine regions out of the traditional boundaries. Moreover, we show that reallocating better-suited grapevine varieties to warmer conditions may be a viable adaptation measure to cope with the projected suitability loss over the traditional regions. However, the effectiveness of this strategy appears to decrease as the level of global warming increases. Overall, these findings suggest the existence of a safe limit below 2°C of global warming for the European winemaking sector, while adaptation might become far more challenging beyond this threshold.

Information on disease resistance patterns of grape varieties may improve disease management.

Resistance to downy mildew (DM) and powdery mildew (PM) contributes to sustainable vineyard management by reducing the diseases and the need for fungicide applications. Resistant varieties vary in their degree of resistance to DM and PM, and in their susceptibility to other diseases. As a consequence, fungicide use may differ among varieties depending on their "resistance patterns" (i.e., the resistance level of a variety toward all of the diseases in the vineyard). The resistance patterns of 16 grapevine varieties to DM, PM, black rot (BR), and gray mold (GM) were evaluated over a 4-year period under field conditions. Disease severity was assessed on leaves and bunches, and the AUDPC (Area Under Disease Progress Curve) was calculated to represent the epidemic progress. GM was found only on bunches and only at very low levels, irrespective of the year or variety, and was therefore excluded from further analyses. The varieties were then grouped into four resistance patterns: i) low resistance to DM and PM, intermediate resistance to BR; ii) high resistance to DM, intermediate resistance to PM, low resistance to BR; iii) intermediate resistance to DM and BR, low resistance to PM; and iv) high resistance to DM, PM, and BR. AUDPC values on leaves were positively correlated with AUDPC values on bunches for susceptible varieties but not for resistant ones, with the exception of PM. Therefore, bioassays with leaves can be used to predict the resistance of bunches to DM and BR for susceptible varieties but not for resistant ones. These results may facilitate both strategic and tactical decisions for the sustainable management of grapevine diseases.

Ecophysiological Response of Vitis vinifera L. in an Urban Agrosystem: Preliminary Assessment of Genetic Variability.

Urban agriculture is an emerging challenge. Identifying suitable agrosystems that allow for the multiple functions of urban agriculture represents a key issue for the reinforcement of the agricultural matrix in cities, with the aims of counteracting and adapting to climate change and providing economic and social benefits. This study aims to produce a preliminary assessment of the adaptability of Italian native and non-native Vitis vinifera L. cultivars to the stressors of an urban environment. The investigation was carried out on the grapevine collection of the Botanical Garden of Rome (“Vigneto Italia”). A total of 15 grapevine varieties were selected for the evaluation of leaf chlorophyll content, stomatal conductance, and chlorophyll fluorescence under abiotic conditions during the growing season of 2021. Spectral signatures were collected from mature leaves, and several vegetation indices (LWI, MCARI, and WBI) were calculated. Our preliminary results highlighted differences in the behavior of the grapevine cultivars. The native ones showed a medium-high level for leaf chlorophyll content (greater than 350 mol m−2), good photosynthetic efficiency (QY > 0.75), and optimal stomatal behavior under drought stress (200 > gs > 50 mmol H2O m−2 s−1). The data allowed for the classification of the tested genotypes based on their site-specific resistance and resilience to urban environmental conditions. The grapevine proved to be a biological system that is highly sensitive to climate variables, yet highly adaptable to limiting growing factors.

The Characterization of Pathotypes in Grapevine Downy Mildew Provides Insights into the Breakdown of Rpv3, Rpv10, and Rpv12 Factors in Grapevines.

We describe a standard method for characterizing the virulence profile of Plasmopara viticola, the causal agent of grapevine downy mildew. We used 33 European strains to inoculate six grapevine varieties carrying the principal factors for resistance to downy mildew (Rpv1, Rpv3.1, Rpv3.2, Rpv5, Rpv6, Rpv10, and Rpv12) and the susceptible Vitis vinifera 'Chardonnay'. For each interaction, we characterized the level of sporulation by image analysis and the intensity of the grapevine hypersensitive response by visual score. We propose a definition for the breakdown of grapevine quantitative resistances combining these two traits. Among the 33 strains analyzed, 28 are virulent on at least one resistance factor. We identified five different pathotypes across the 33 strains analyzed: two pathotypes overcoming a single resistance factor (vir3.1 and vir3.2) and three complex pathotypes overcoming multiple resistance factors (vir3.1,3.2; vir3.2,12; vir3.1,3.2,10). Our findings confirm the widespread occurrence of P. viticola strains overcoming the Rpv3 haplotypes (28 strains). We also detected the first breakdown of resistance to the Rpv10 by a strain from Germany and the breakdown of Rpv12 factors by a strain from Hungary. The pathotyping method proposed here and the associated differential host range lay the groundwork for the early detection of resistance breakdown in grapevines. This approach will also facilitate the monitoring of the evolution of P. viticola populations at large spatial scales. This is an essential step forward to promoting durable management of the resistant grapevine varieties currently available.

Prospecting the Resilience of Several Spanish Ancient Varieties of Red Grape under Climate Change Scenarios.

Climate change results in warmer air temperatures and an uncertain amount and distribution of annual precipitations, which will directly impact rainfed crops, such as the grapevine. Traditionally, ancient autochthones grapevine varieties have been substituted by modern ones with higher productivity. However, this homogenization of genotypes reduces the genetic diversity of vineyards which could make their ability to adapt to challenges imposed by future climate conditions difficult. Therefore, this work aimed to assess the response of four ancient grapevine varieties to high temperatures under different water availabilities, focusing on plant water relations, grape technological and phenolic maturity, and the antioxidant capacity of the must. The study was conducted on fruit-bearing cuttings grown in pots in temperature-gradient greenhouses. A two-factorial design was established where two temperature regimes, ambient and elevated (ambient + 4 °C), were combined with two water regimes, full irrigation and post-veraison deficit irrigation, during fruit ripening. There were significant differences among the ancient varieties regarding plant water relations and fruit quality. This research underlines the importance of evaluating the behavior of ancient grapevine varieties that could offer good options for the adaptation of viticulture to future climate conditions.

Discrimination of genetic and geographical groups of grape varieties (Vitis vinifera L.) based on their volatile organic compounds.

Grape volatile organic compounds (VOCs) play an important role in the winemaking industry due to their contribution to wine sensory characteristics. Another important role in the winemaking industry have the grapevine varieties used in specific regions or countries for wine production. Due to the high variability of grapevine germplasm, grapevine varieties are as classified based on their genetic and geographical origin into genetic-geographic groups (GEN-GEO). The aim of this research was to investigate VOCs in 50 red grapevine varieties belonging to different GEN-GEO groups. The study included varieties from groups C2 (Italy and France), C7 (Croatia), and C8 (Spain and Portugal). The analysis of VOCs was performed by SPME-Arrow-GC/MS directly from grape skins. The analyzed VOCs included aldehydes, ketones, acids, alcohols, monoterpenes, and sesquiterpenes. The most abundant VOCs were aldehydes and alcohols, while the most numerous were sesquiterpenes. The most abundant compounds, aldehydes and alcohols, were found to be (E)-2-hexenal, hexenal, (E)-2-hexen-1-ol, and 1-hexanol. Using discriminant analysis, the GEN-GEO groups were separated based on their volatile profile. Some of the individual compounds contributing to the discrimination were found in relatively small amounts, such as benzoic acid, (E,E)-2,4-hexadienal, 4-pentenal, and nonanoic acid. The groups were also discriminated by their overall volatile profile: group C2 was characterized by a higher content of aldehydes and alcohols, and group C8 was characterized by a higher content of sesquiterpenes and acids. Group C7 was characterized by all low amount of all classes of VOCs.

Reducing the Losses of Three Local Grape Varieties (Vitis vinifera L.) by Cool Storage Period.

Three local varieties of grapevine (Vitis vinifera L. Jnoby, Sulaimana- Rash and Zaitony); were taken from a private vineyard in Sian village, Dinarta, Duhok, Kurdistan region-Iraq after the distinctive signs of maturity appeared for each variety from healthy grapevines of 6-years old which planted at 2×3 m spacing and irrigated by drip irrigation system for study the effect of storage periods (0, 20, 40 and 60 days at 2±1 °C and 83-88% RH) on chemical and physical characteristics plus the loss of grape berries and clusters. The vines received conventional cultivation practices with regular winter and summer pruning, weed and diseases control. Berry shattering, spoilage, weight loss, total loss and rachis condition for the varieties were estimated as a function to storage in this study. Results showed that the maximum berry shattering (1.71%) was recorded in Sulaimana-Rash variety showing a significant difference with Jnoby variety (0.48%). The highest values of percent spoilage and total loss were recorded in variety Zaitony (20.17 and 26.36%) respectively. The maximum weight loss (10.24 %) was recorded in variety Jnoby which was significantly higher than the other two varieties (Sulaimana-Rash and Zaitony). Spoilage percentage, weight loss and total loss significantly increased with increasing storage periods (23.48, 12.13 and 32.83%) respectively. There were significant interaction effects on weight loss and total weight loss percentages among the varieties, the storage periods showed a maximum value was started after 60 days of the beginning of storage (14.33%) in Jnoby variety, while highest total loss (60.25%) was recorded in Zaitony.

A Field Collection of Indigenous Grapevines as a Valuable Repository for Applied Research.

The grapevine is an economically important plant, with a historical connection to the development of human culture. Currently, over 6000 accessions are known as individual grapevine varieties, some of which are important to national heritage, valuable for current viticultural practices, and as genetic resources to maintain plasticity under changing climatic conditions, environmental sustainability, and market demands. Recently, the diversity of cultivated grapevines has declined significantly, due to the increased focus of global wine industries on a few major cultivars. Moreover, due to biotic and abiotic stresses, the wild V. vinifera germplasm’s genetic diversity has declined, with some varieties on the verge of extinction. Vitis germplasm conservation can be achieved via either in situ (e.g., protected areas) or Ex situ (e.g., field collections, seed banks, and tissue culture collections) methods. This study aims to highlight the importance of Vitis field bank collections. We demonstrate the research done in the Israeli indigenous Vitis vinifera collection. The multi-layer analysis of the varieties enabled the identification of drought stress-resistant varieties, and suggested a mechanism for this resistance through noting the dramatic phenological differences in foliage development between resistant and sensitive varieties. In addition, we show a general characterization of the varieties via major grape characteristics, including bunch and berry shape, as well as their possible utilization based on their aromatic and phenolic profiles.

Scaphoideus titanus fitness on grapevine varieties with different susceptibility to Flavescence dorée phytoplasma

AbstractScaphoideus titanus (Ball) is a Nearctic leafhopper (Cicadellidae: Deltocephalinae), monophagous on Vitis spp., naturalized in European vineyards since the 20th century. Following its introduction and establishment in Europe, S. titanus became the main vector of Flavescence dorée phytoplasma (FDp) to grapevine. FDp causes heavy economic losses to viticulture in Europe. The control of the disease mainly relies on insecticide applications against the vector and on the removal of infected plants. The exploitation of plant resistance or tolerance against pathogens and pests can represent a valuable tool for a more sustainable viticulture. The first step in identifying resistance traits in grapevine varieties towards S. titanus is the evaluation of insect fitness parameters on different grapevine genotypes. Therefore, in this work, nymph mortality and developmental time, adult survival and prolificacy of S. titanus have been studied on three grapevine varieties, characterized by different susceptibility to FD. Scaphoideus titanus showed highest fitness when reared on Barbera, whereas the worst performances were recorded on Moscato, with a significant reduction in nymph and adult survivals, a slowed nymph development, and a decreased number of available eggs. On Brachetto, S. titanus showed an intermediate level of fitness parameters. Consistently with previous studies on feeding behaviour, Barbera is the most suitable host for the FD‐vector. The high suitability of Barbera for S. titanus may partly explain the high susceptibility to FD of this variety. On the contrary, the low suitability of Moscato, poorly susceptible to FD, may be due to antibiosis and antixenosis defence mechanisms that act against S. titanus.