Quantitative analysis of the berry size in grapevine cultivar ‘Italia’ •

Quantitative evaluation of the horticultural crops has high importance to identify cultivars, describe the effect of the growing location and cultivation technology or define consumer's preference regarding the size and shape. Fruit traits of the grapevine (Vitis vinifera L.) are mainly described by the bunch and berry morphology notably bunch and berry size, weight and shape. Ampelographers particularly evaluate the berry based on the seed number as it influences size and consumers' decision. In this study, berry morphological traits of the grapevine cultivar ‘Italia’ was investigated based on digital image analysis. Samples were collected from two vineyards in Hungary with different ecological and cultivation circumstances. Altogether 12 traits were investigated: weight, seed number, size and shape attributes. Results showed that berry morphological traits – except from the shape attributes – are not differing between the two sampling locations. In accordance with previous studies, seed number – ranging from 0 to 4 – had noticeable effect on the size attributes.

EFFECT OF FOLIAR APPLICATION OF ZINK AND SALICYLIC ACID ON VEGETATIVE GROWTH AND YIELD CHARACTERISTICS OF HALAWANI GRAPE CULTIVAR (Vitis vinifera L.)

THis investigation aimed to study the effect of foliar application with zinc alone or in combination with salicylic acid on vegetative growth, yield, physical and chemical properties of Halawani grapevine cultivar during two successive seasons (2017 and 2018). Zinc was used at concentration of 2 and 4 g.L-1 in a chelated form and salicylic acid at concentration of (50, 100 and 150 mg. L-1) in addition to control treatment for each of them. The result obtained proved that all parameters such as leaf area, total chlorophyll, number and weight of cluster, yield, berries size and weight, as soon as TSS, total sugar, juice percentage and density, β-carotenes, Zn, N. proline content of leaves were increased significantly as compared with control, while total acidity and total phenols were decreased by all treatments as compared with control. Furthermore, combination between high concentration of zinc and salicylic acid improved all parameters in comparison with the control.

Automated Grapevine Cultivar Identification via Leaf Imaging and Deep Convolutional Neural Networks: A Proof-of-Concept Study Employing Primary Iranian Varieties

Extending over millennia, grapevine cultivation encompasses several thousand cultivars. Cultivar (cultivated variety) identification is traditionally dealt by ampelography, requiring repeated observations by experts along the growth cycle of fruiting plants. For on-time evaluations, molecular genetics have been successfully performed, though in many instances, they are limited by the lack of referable data or the cost element. This paper presents a convolutional neural network (CNN) framework for automatic identification of grapevine cultivar by using leaf images in the visible spectrum (400–700 nm). The VGG16 architecture was modified by a global average pooling layer, dense layers, a batch normalization layer, and a dropout layer. Distinguishing the intricate visual features of diverse grapevine varieties, and recognizing them according to these features was conceivable by the obtained model. A five-fold cross-validation was performed to evaluate the uncertainty and predictive efficiency of the CNN model. The modified deep learning model was able to recognize different grapevine varieties with an average classification accuracy of over 99%. The obtained model offers a rapid, low-cost and high-throughput grapevine cultivar identification. The ambition of the obtained tool is not to substitute but complement ampelography and quantitative genetics, and in this way, assist cultivar identification services.

Variable Populations of Grapevine Virus T Are Present in Vineyards of Hungary

Grapevine virus T (GVT) is a recently described foveavirus, which was identified from a transcriptome of a Teroldego grapevine cultivar in 2017. Recently, we surveyed vineyards and rootstock plantations in Hungary using small RNA (sRNA) high-throughput sequencing (HTS), at a time when GVT had not yet been described. A re-analysis of our sRNA HTS datasets and a survey of grapevines by RT-PCR revealed the presence of GVT in most of the vineyards tested, while at rootstock fields its presence was very rare. The presence and high variability of the virus in the country was confirmed by sequence analysis of strains originating from different vineyards. In this study, we demonstrate the presence of GVT in Hungary and show its high diversity, suggesting that GVT presence may not seriously affect grapevine health and that it could have been present in European vineyards for a long time as a latent infection.

MADS-Box Protein Complex VvAG2, VvSEP3 and VvAGL11 Regulates the Formation of Ovules in Vitis vinifera L. cv. ‘Xiangfei’

The phenomenon of multi-carpel and multi-ovule exists in the grapevine cultivar ‘Xiangfei’, but the mechanism of ovule formation is seldom reported. In this study, we observed the ovule formation process by using ‘Xiangfei’ grapes. The role of the VvAG2 (VvAGAMOUS) gene in ovule formation was identified, and we explored the relationship between VvAG2, VvSEP3(VvMADS4) and VvAGL11(VvMADS5) proteins. The results showed that the ovule primordium appeared when the inflorescence length of ‘Xiangfei’ grapes were 4–5 cm long; the relative expression levels of VvAG2, VvAGL11 and VvSEP3 genes were higher during ovule formation, and the expression levels of VvAG2 gene was the highest. Transgenic tomato (Solanum lycopersicum) plants expressing VvAG2 produced higher numbers of ovules and carpels than the wild type. Moreover, yeast two-hybrid and yeast three-hybrid experiments demonstrated that VvSEP3 acts as a bridge and interacts with VvAG2 and VvAGL11 proteins, respectively. Meanwhile, a homodimer can be formed between VvSEP3 and VvSEP3, but there was no interaction between VvAG2 and VvAGL11. These findings suggest that the VvAG2 gene is involved in the formation of ovules, and VvAG2/VvSEP3 together with VvAGL11/VvSEP3 can form a tetrameric complex. In summary, our data showed that VvAG2 along with VvSEP3 and VvAGL11 jointly regulate the ovule formation of ‘Xiangfei’ grapes.

Health Beneficial Properties of Grapevine Seed Extract and Its Influence on Selected Biochemical Markers in the Blood, Liver and Kidneys of Rattus norvegicus

Cadmium (Cd) is a heavy metal that occurs in all areas of the environment, including the food chain. In the body, it causes oxidative stress by producing free radicals that are harmful to the cells. Grape seed extract (GSE) contains a wide range of biologically active components that help to neutralize the adverse effects of free radicals. In this study, the effects of GSE prepared form semi-resistant grapevine cultivar Cerason, which is rich in phenolics, on biochemical markers of brown rats exposed to the effects of cadmium were monitored. GSE increased the plasma antioxidant activity and, in the kidneys and the liver, Cd content was significantly lowered by GSE co-administration. Accordingly, the increase in creatinine content and alanine aminotransferase activity and the decrease of catalase and superoxide dismutase activities caused by cadmium were slowed down by GSE co-administration. The results of this work reveal that grape seed extract offers a protective effect against the intake of heavy metals into the organism.

Evaluation of the effect of foliar treatment with "Algae Super" preparation on the productivity and quality indicators of grapes

Представлены результаты исследования эффективности системы минерального питания на основе препарата «Алга Супер» (компания ООО «АгроБиоКом») в качестве внекорневой подкормки винограда, дана оценка её влияния на формирование урожайности и показателей качества винограда столового сорта Италия и технического сорта Ркацители. Применение экспериментальной системы внекорневых обработок способствовало увеличению урожайности сортов Италия и Ркацители на 30,1 % относительно контроля. Отмечено увеличение выхода стандартной продукции сорта Италия на 4,1 % по сравнению с контролем. При использовании препарата «Алга Супер» массовая концентрация сахаров увеличилась в среднем на 3,1 % (P = 2,59*10), на фоне уменьшения массовой концентрации титруемых кислот, на 6,0-6,5 % относительно контрольных вариантов. Общая дегустационная оценка винограда сорта Италия после обработок была выше контроля на 7,1 %. Возделывание винограда с применением препарата «Алга Супер» обусловило снижение себестоимости урожая сорта Италия на 22,8 %, сорта Ркацители - на 22,1%, на фоне увеличения рентабельности возделывания на 125,4 и 58,7 % соответственно. The results of the study on the efficiency of mineral nutrition system based on the preparation "Algae Super" ("AgroBioCom" LLC Company) as foliar treatment of grapes are presented, evaluation of its effect on the formation of grape productivity and quality indicators of table grape cultivar ‘Italia’ and wine grape cultivar ‘Rkatsiteli’ is given. Using of experimental system of foliar treatments contributed to an increase in the cropping capacity of grapevine cultivars ‘Italia’ and ‘Rkatsiteli’ by 30.1% relative to the control. An increase in the yield of standard products of the ‘Italia’ cultivar by 4.1% in comparison with the control was registered. When using the "Algae Super" preparation, the mass concentration of sugars has increased by an average of 3.1% (P = 2.59*10), against the background of a decrease in the mass concentration of titratable acids - by 6.0-6.5%, relative to the control variants. The overall tasting evaluation of the ‘Italia’ grapevine cultivar after treatments was 7.1% higher than the control. The cultivation of grapes when using the preparation “Algae Super” led to a decrease in the final cost of the yield of the cultivars ‘Italia’ - by 22.8%, and ‘Rkatsiteli’ - by 22.1%, against the background of cultivation profitability increase by 125.4 and 58.7%, respectively.

Structural and molecular characterization of the Rpv3 locus towards the development of KASP markers for downy mildew resistance in grapevine (Vitis spp.)

Plasmopara viticola is the oomycete that causes downy mildew in grapevine. Varying levels of resistance to P. viticola across grape cultivars allowed quantitative trait loci to be identified. The Rpv3 locus is located at chromosome 18, in a region enriched in TIR-NBS-LRR genes, and the phenotype associated is a high hypersensitive response. In this work, we aimed to identify candidate genes associated with resistance to downy mildew on the Rpv3 locus and to evaluate their transcriptional profiles in a susceptible and a resistant grapevine cultivar after challenging with P. viticola. Candidate genes were identified by representational differential analysis and also by functional enrichment tests. Many predicted genes associated with resistance to diseases were found at the Rpv3 locus. In total, seventeen genes were evaluated by RT-qPCR. Differences in the steady-state expression of these genes were observed between the two cultivars. Four genes were found to be expressed only in Villard Blanc, suggesting their association to the hypersensitivity reaction. Concerning marker assisted-selection for downy mildew resistance, we show the efficient use of a haplotype of SSR markers. Furthermore, based on Rpv3-located SNPs between grapevine cultivars contrasting in downy mildew resistance, we developed and tested forty-one new markers for assisted selection. After genotypic and phenotypic evaluations on segregant populations, two markers, Rpv3_15 and Rpv3_33, were considered efficient for downy mildew resistance identification. This study constitutes an in-depth genomic characterization of the Rpv3 locus, confirms its involvement in resistance against P. viticola infection and presents promising biotechnological tools for the selection of young resistant individuals.

Responses to Drought Stress Modulate the Susceptibility to Plasmopara viticola in Vitis vinifera Self-Rooted Cuttings

Climate change will increase the occurrence of plants being simultaneously subjected to drought and pathogen stress. Drought can alter the way in which plants respond to pathogens. This research addresses how grapevine responds to the concurrent challenge of drought stress and Plasmopara viticola, the causal agent of downy mildew, and how one stress affects the other. Self-rooted cuttings of the drought-tolerant grapevine cultivar Xynisteri and the drought-sensitive cultivar Chardonnay were exposed to full or deficit irrigation (40% of full irrigation) and artificially inoculated with P. viticola in vitro or in planta. Leaves were sampled at an early infection stage to determine the influence of the single and combined stresses on oxidative parameters, chlorophyll, and phytohormones. Under full irrigation, Xynisteri was more susceptible to P. viticola than the drought-sensitive cultivar Chardonnay. Drought stress increased the susceptibility of grapevine leaves inoculated in vitro, but both cultivars showed resistance against P. viticola when inoculated in planta. Abscisic acid, rather than jasmonic acid and salicylic acid, seemed to play a prominent role in this resistance. The irrigation-dependent susceptibility observed in this study indicates that the practices used to mitigate the effects of climate change may have a profound impact on plant pathogens.