Optical Properties of Berry Epicuticular Waxes in Four Georgian Grape Cultivars (Vitis vinifera L.)

The epidermis of plant shoot organs is generally covered by epicuticular waxes. The role of this layer isrelated mainly to the protection of the inner tissues from biotic and abiotic stresses. In this study, attentionis focused on the optical properties of the berry epicuticular waxes of the grapevine (Vitis vinifera L.) atfruit ripening. The reflectance of the berry surface was measured before and after chloroform treatmentsin four Georgian grape cultivars grown in northern Italy. Epicarp optical properties were underlinedat different wavelengths (341 to 1025 nm) for each cultivar. The results show that the berry waxes haveseveral optical properties; it is possible that their main eco-physiological effect is to provide specificprotection against different types of radiation. Besides the physiological aspects, the results are interestingalso from a technical point of view in the field of interpretation of reflectance measurements carried out bynon-invasive instruments

Comparison between the Grape Technological Characteristics of Vitis vinifera Subsp. sylvestris and Subsp. sativa

none7siWine has been produced in Georgia since the 6th millennium BC. The processes of cultivar selection and breeding started with wild grapes Vitis vinifera L. ssp. sylvestris Gmel. and included multiple introgression events—from the wild to domestication. This article aims at improving the knowledge concerning the history of winemaking through a comparison of the Vitis vinifera subsp. sylvestris and subsp. sativa. Grapes of Vitis vinifera subsp. sylvestris were grown in an ampelographic collection and vintages 2017–2020 were analyzed. The obtained data were compared to a wider dataset available in literature concerning Vitis vinifera subsp. sativa, demonstrating the central role of grape morphology in the domestication process. This evidence suggests that the technological value of the cultivars played an important role in the selection process. In vintages 2017, 2018, and 2019, wines were produced with Vitis vinifera subsp. sylvestris grapes and compared with Cabernet Sauvignon and Saperavi vinifications. For all the vintages, the fermentations took shorter time for wild grape, despite the highest content of total phenols. Learning from the past, Vitis vinifera subsp. sylvestris might still be an interesting genetic resource for future breeding programs. Furthermore, the possible combination of wild and domesticated grapes can make possible the production of wines with long ageing, exalting their own characteristics.openMaghradze, David; Kikilashvili, Shengeli; Gotsiridze, Olan; Maghradze, Tamar; Fracassetti, Daniela; Failla, Osvaldo; Rustioni, LauraMaghradze, David; Kikilashvili, Shengeli; Gotsiridze, Olan; Maghradze, Tamar; Fracassetti, Daniela; Failla, Osvaldo; Rustioni, Laur

Clarification of homonymy (misnaming) for a grapevine cultivar in Georgia: the case of 'Moldova' alias 'Aladasturi'

Two different grape cultivars are grown in Georgia under the name 'Aladasturi', one in the West and one in the East part of the Country. Investigation of ampelographic and ampelometric parameters and nuclear microsatellite markers demonstrated, that the cultivar from West Georgia is the real Georgian autochthonous wine and table grape cultivar 'Aladasturi', while the cultivar from East Georgia is the table grape cultivar 'Moldova' with high resistance to downy mildew, obtained in the Republic of Moldova in the 1960s. This cultivar was probably introduced to Georgia in the period of 1970-1980s. Similarity of berry and bunch characteristics of 'Moldova' and 'Aladasturi' might be the reason for creation of homonymy, respectively misnaming. The homonymous 'Aladasturi' finally turned out to be a misnomer

Analysis of agroclimatic resources for Georgian viticulture

One of the results of the \u201cResearch Project for the Study of Georgian Grapes and Wine Culture\u201d promoted by the National Wine Agency of the Republic of eorgia was the production of a bilingual handbook for modern viticulture. The first sections of the handbook were devoted to the agrometeorological analysis of environmental resources and limitations, comprising a general analysis of Georgian climate and agrometeorological features, followed by detailed regional cards. The agrometeorological analysis of Georgia was based on daily data collected by National and International networks for the period 1974-2013. Several agrometeorological indexes were calculated in order to define resources and limitations for viticulture for each viticultural region of Georgia, providing fundamental information for grape-growing and wine-making

Type of pollination and indices of fruit set of some Georgian grapevine varieties

Pollen characteristics (length, width, diameter, number of pores and stain ability), type of pollination, fruit set and number of seeds per berry of the eight Georgian autochthonous grapevine varieties Rkatsiteli, Saperavi, Gorula, Gorula no. 21, Tsulukidzis Tetra, Alexandrouli, Mujuretuli and Orbeluri Ojaleshi have been investigated. It is concluded that for fruitset of the tested hermaphrodite grapevine varieties, self-pollination plays a predominant role, but in addition crosspollination is necessary for their high fruitset.

Field genebank standards for grapevines (Vitis vinifera L.)

Annex

Ampelographic study of Vitis vinifera L. varieties maintained in Shida Kartli (Georgia)

Research Not

Screening of Georgian grapevine germplasm for susceptibility to downy mildew (Plasmopara viticola)

Downy mildew, caused by the obligate biotrophic parasite Plasmopara viticola, is one of the most serious grapevine diseases with worldwide distribution. Resistant grapevines can be used to reduce damages caused by the pathogen, recently different levels of susceptibility to P. viticola were detected in some Georgian autochthonous varieties.  The aim of the present work was to classify additional Georgian autochthonous varieties into different groups according to their susceptibility to the downy mildew agent in the framework of COST Action FA1003 "East-West Collaboration for Grapevine Diversity Exploration and Mobilization of Adaptive Traits for Breeding". The leaf disk assay defined by the OIV 452-1 protocol was used for screening 61 native varieties of Georgia. Screened varieties showed different degree of resistance: very high – 7 accessions, high - 13, medium - 15, low – 23, and very low - 3 accessions. The results suggest that further resistant genotypes are likely to be found within more than 500 Georgian grapevine cultivars

Vitis vinifera subsp. sylvestris and sativa; so far, so close: a 20 SSR based comparison of the two taxa

In Vitis vinifera L., the hypothesis of secondary domestication center, located along the wild progenitor distribution areas, is suggestive and credible even if up to now close parentage relationships between domestic (Vitis vinifera L. subsp. sativa (DC.) Hegi) and wild (Vitis vinifera L. subsp. sylvestris (Gmel.) Hegi) grapevines have not been detected, possibly due to century long separation of the two subspecies. The aim of this work was to verify the possibility of tracing a flow between the two compartments basing on molecular data and thanks to the availability of a huge dataset comprising 645 wild and more than 1400 cultivated samples. Twenty SSR loci were used to describe and genotype both sylvestris and sativa compartments. The sylvestris samples were all collected in the frame of a three year census in Italy and are representative of the Italian distribution range from north to south. The cultivated sativa accessions mainly (1231 samples) belong to the Vassal (INRA-Montpellier) collection, while the remaining (200) were selected in the frame of the Italian grapevine germplasm. Results highlighted a high level of genetic diversity for both wild and cultivated groups. STRUCTURE analysis clearly evidenced the separation of the two compartments and no first or second degree relationships were evidenced between the two subspecies