ივეტა მეგრელიშვილი

In recent years the symptoms characteristic for a disease of phytoplasma etiology,widely distributed in Europe - Flavescence Doree Phytoplasma (FD) - are registered on red-fruited varieties in newly planted vineyards in Georgia.

12 grapevine varieties (“Tempranillo”, “Alicante”,”Mercy”, “Kistauruli sagvine”, “Black magic”, “Bastard”, “Crimson sidles”, “Merlo”, “Albane”, “Italia”,”Baga”, “Grenache”) were investigated for detection of phytoplasma associated with flavescence doree in the east part of Georgian vineyards including mother stock and collection vineyards. 145 samples were tested using a double antibody sandwich-enzyme linked immunosorbent (DAS-ELISA) assay according to manufacturer’s instructions (SEDIAG) and triplex real-time PCR assay was applied with TaqMan minor groove binder probes (TaqMan-MGB). Two set of primers and probes pair were used for the detection of FD in the same samples of grapevines in order to compare the efficacy for each one.

Based on DAS-ELISA results infection was not found in any researched samples. Obtained results from triplex real-time PCR assay showed that both set of primers pair were sensitive for FD identification. The presence of infection in grapevine cultivars such as “Kistauruli sagvine”, “Black magic”, “Bastard”, “Crimson sidles” was confirmed with both set of primers and probes.

Among tested grapevine samples out of 145 samples 4.79% were infected when tested using primers and probes set I. In case of primers and probes set II infection rate comprised 1.71% respectively.

Study revealed that DAS-ELISA assay is not effective and reliable method for the identification of  Flavescence Doree Phytoplasma while molecular approaches like triplex real-time PCR can be considered as an accurate and confirmatory assay with high performance.

Flavescencedorée (FD) and Bois noir (BN) are two grapevine yellows diseases (GY), associated with phytoplasmas considered quarantine pests in Georgia.Symptoms of diseases caused by phytoplasmas were observed in Georgian vineyards, showinga wide distribution of grapevine yellows in the Country. The main goal of the research was to study grapevine yellows phytoplasma diseases in Georgian region of Kakheti (villages Kondoli, Napareuli, Tsinandali) on three international grapevine varieties (Chardonnay, Sauvinion blanc, Tempranillo), and Georgian variety Khikhvifor selection of phytoplasma disease-free grapevine varieties in order to develop plant sanitary system in Georgia. Totally 259 symptomatic and asymptomatic grapevine samples were analyzed using a new triplex real-time PCR assay with TaqMan minor groove binder probes (TaqMan-MGB), and a Double Antibody Sandwich-Enzyme linked Immunosorbent Assay (DAS-ELISA) with commercial complete Kit DAS ELISA Poly/Mono (Biotin) (SEDIAG). According to triplex real-time PCR TaqMan assay 38 out of 259 tested samples reacted positively, whereas infection was not found in any researched samples by DAS-ELISA, indicating that the latter technique is not suitable for phytoplasma detection. Phytoplasmas associated with Flavescencedoree(6.3%) and Bois Noir (11.8%) were found in symptomatic plants of the cultivar Chardonnay (6.3% and 11.8% of the examined samples, respectively) and Tempranillo (3.4% and 4.2% of the examined samples, respectively). Symptomatic plants of the cultivar Khikhvi were found infected exclusively by FD phytoplasma (5.1% of the examined samples), while no phytoplasma infection was detected in the cultivars Sauvinion blanc. Interestingly, result highlighted the first report of Flavescencedoree (FD) phytoplasma in grapevine varieties Chardonnay, Tempranillo, and 'Khikhvi' in Georgia.

Grapevine storage is still a major concern in Georgia. Metabolic processes results in a considerable reduction in nutritional properties during storage.

The research aim was to study the effect of calcium chloride and eucalyptus extract on the grape cultivar “Italia” during storage. 7kg Grape were treated with different combination of calcium chloride and eucalyptus before storage:; 1.5% calcium chloride+ 1% eucalyptus extract; 2% calcium chloride+ 1% eucalyptus extract. Control_ 7kg Grape.

The level of dry matter, total sugar, acidity and ascorbic acid were evaluated before storage, in the middle and at the end. Dry mass was determined using refractometer, total sugar were measured by Bertrand’s method, titratable acidity (g/100ml) using 0.1 N NaOH to a phenolphthalein end point or to a pH of 8.2, ascorbic acid (mg / 100 ml) by redox titration of 10 ml of I2 in grape juice. 

As a results showed 2% calcium chloride+ 1% eucalyptus extract can improve storability of cultivar “Italia”. The parameters of titratable acid and ascorbic acid were stabile (reduced only 0.6% and 1.4% respectively) during storage compared to others including control (3.1% and 3.3%).

A slight change of dry matter and total sugar was detected in all treated grapes accordingly 0.8% and 0.6%, but loss in control was reached to 1.7% and 2.4%.

Finally, it was revealed that 2% CaCl2 + 1% eucalyptus extract can used as a safe compound during long-tern storage for enhance storability of grape cultivar “Italia”. This is the first storage technology development by the Biotechnology Center in Georgia.

Grapes are one of the most unstable crops in terms of storage, which is related to its botanical-morphological structure. The aim of our work was to study effect of sodium metabisulfite (SMB) on the most popular Georgina grapevine cultivars “Rkatsiteli” and “Tbilisuri” during Storage. p7 7 kg packed grapes into carton boxes were treated with tree concentration (15g; 25g; 35g) of SMB under cold storage at 0-10C, humidity 90-95% for 120 days to improve storability of grapes varieties: Control- 7kg- no treated grape.

Monitoring of weight loss, dry matter concentration (DMC) sugars and acidity were conducted at the beginning of storage, in the middle (60 days) and at the end of storage (120days). Sugar were measured by Bertrand’s method, dry mass using refractometer, 0.1 N NaOH was used to titrate acidity (g/100ml) to a phenolphthalein end point or, alternatively, to a pH of 8.2.

25g SMB treatments provided the best result to compare others, with weight loss of 6.7% in cultivar “Tbilisuri,” and 8.3% in cultivar “Rkatsiteli,”while weight reduction in control reached 9.8% at the end of storage.

The effect of 15g and 25g SMB was the same on changing the amount of sugars both in the “Tbilisuri” -0/7% (20.8%-20.1%) as in the “Rkatsiteli” -1.2% (20.3%-19.1%).

Significant reductions were observed in acidity at the end of storage using all concentration of SMB. Decrease of acidity was the equally in both grapevine cultivars-2.2% („Tbilisuri“ -5.6%-3.4%; „Rkatsiteli“ - 4, 8%-2,6 %)however it is fully suitable with the amount of sugar, flavor and pulp consistency.

Experimental research allows us to conclude that for long-term storage most effective is to use 25 g SMB tablets per 7 kg of grapes. In addition, no grain loss was observed compared to the other variants, which is one of the most important point in the long-term storage of grapes.

Development of in vitro micro tuber production is actual for in vitro elit seed production technology. It is known that growth hormones with combination sucrose plays important role in potato in vitro regeneration; response of potato varieties on different medium depends on their genetics and endogenous hormones concentration. The present investigation was carried out to select best MS medium protocol and identify perfect hormonal/sucrose combination for three varieties of potato

Microbial diseases have been reported in the walnut orchards due to different reasons in recent years in Georgia. For the purpose of walnuts tissue cultures reproduction, it is necessary to determine the optimal type of sterilization of initial material. The aims of this study were determined optimal sterilization type to propagate walnuts cultivars ‘Pedro’, and ‘Chandler’ using tissue culture technique. The initial explants (unimodal micro cuttings with a length between 1 and 1.2 cm) of three cultivars were collected from the young 2-3 years old walnuts orchards, Dzevera, ShidaKartli, Georgia. Two sterilized types were used for in vitro propagation of walnuts: I.1-2% hypochlorite 10-15 min, followed 70 % alcohol -30 min and 3 times sterile distillate water II. 0.1% mercuric chloride 5 min and 3 times sterile distillate water. It was revealed that microbial contamination were 58.97% using 0.1% mercury chloride and relatively high by sodium hipocloride-85.12%. DKW medium was used for in vitro cultivation of walnuts cultivars supplemented with 0.1 mg/L IBA, 1 mg/L BAP and sucrose 3%. The pH of culture medium was adjusted at 5.5 before adding the gelling agent and autoclaving. Micro cuttings were kept at 25±2°C under a 16 h photoperiod. Finally, optimal sterilization types of initial explants (Combination II) was determined. Walnuts cultivars: ‘Pedro’ and ‘Chandler’ were propagated using tissue culture methods first time in Georgia. This study led to develop an effective method for micro propagation of Juglansregia, which enable us to establish new walnuts orchards in Georgia.

In this study, the effect of Eucalyptus extract and calcium chloride (CaCl2) on grape storage ability was investigated. The treatment includes control (Sulfur dioxide (SO2) 20-30 minutes exposure, once a month) and two combinations: I. 1% CaCl2+0.5% Eucalyptus extract; II. 2% CaCl2+1% Eucalyptus extract. Two grape varieties: Italia and Alphonse Levallee were selected for the study, which are the most popular cultivars among consumers in Georgia. After the treatments grape were stored at 0-1°C, relative humidity of 85-90%. Evolution of qualitative features such as percentage of decay caused by microbiological and physiological diseases was done in the middle of the storage (60 days) and at the end of the storage (120 days). Results showed that the loss caused by microbiological and physiological diseases in the middle stage of the storage (60 days) on two species grapes was unimportant control- 0.9%; with the 1% CaCl2+0.5% Eucalyptus extract-1.5% and 2% CaCl2+1% Eucalyptus extract-1%. Therefore, at the end of the storage (120 days) control loss was 6.1%; on condition 1% CaCl2+0.5% Eucalyptus extract-11.4% and 2% CaCl2+ 1% Eucalyptus extract-7.3%. Thus, 2% CaCl2+1% Eucalyptus extract solution showed the best result from the combined compounds, loss after storage was 7.3%. Sulfur dioxide (SO2) condition loss was less but it is noteworthy that the solution of 2% CaCl2+1% Eucalyptus extract is an ecologically pure mix and the stored grapevines are ecologically pure products, which is a key factor in choosing a storage facility.

Plant viruses can cause loss of yield and quality in a lot of important crops. Symptoms of pathogens are variable depending on the cultivars and virus strain. Selection of resistant potato varieties would reduce the risk of virus transmission and significant economic impact. Other way to avoid reduced harvest yields is regular potato seed production sampling and testing for viral infection. The aim of this study was to determine the occurrence and distribution of viral diseases according potato cultivars for further selection of virus-free material in Georgia. During the summer 2015-2016, 5 potato cultivars (Sante, Laura, Jelly, Red Sonia, Anushka) at 5 different farms located in Akhalkalaki were tested for 6 different potato viruses: Potato virus A (PVA), Potato virus M (PVM), Potato virus S (PVS), Potato virus X (PVX), Potato virus Y (PVY) and potato leaf roll virus (PLRV). A serological method, Double Antibody Sandwich-Enzyme linked Immunosorbent Assay (DAS-ELISA) was used at the laboratory to analyze the results. The result showed that PVY (21.4%) and PLRV (19.7%) virus presence in collected samples was relatively high compared to others. Researched potato cultivars except Jelly and Laura were infected by PVY with different concentrations. PLRV was found only in three potato cultivars (Sante, Jelly, Red Sonia) and PVM virus (3.12%) was characterized with low prevalence. PVX, PVA and PVS virus infection was not reported. It would be noted that 7.9% of samples were containing PVY/PLRV mix infection. Based on the results it can be concluded that PVY and PLRV infections are dominant in all research cultivars. Therefore significant yield losses are expected. Systematic, long-term control of potato viral infection, especially seed-potatoes, must be regarded as the most important factor to increase seed productivity.

The research aim was to determine optimal in vitro condition for propagation different maturity potato cultivars. Potato varieties were collected from in vitro potato collection of Georgian Technical University, Biotechnology Center according to their maturity: Early cultivars: Viviana, Red Sonia, Bellarosa, Vineta, Anushka; Medium early: Donata, Bernina, Madeira, Sante, Laura. Medium late: Brodie, Shepody, Jelly, Carola, Desiree.

The influence of three types of combinations with temperature, humidity, light and photoperiod was studied on all three maturity potato cultivarʼs in vitro development:I. T-23-25° C, H-80%, Lux-5-5500, 16h; II. T-25-27° C, H-75%, Lux-5-5500,16h: III. T-27-29° C, H-70%, Lux-5-5500, 16h;The results were evaluated after 17 days of reproduction. Best in vitro condition for all researched potato varieties was selected for their leave colors, rooting, and shoot formation. All potato cultivars morphological characterization was variable depending on the type of in vitro condition. It was revealed early maturity cultivars had maximum potential for in vitro propagation (5-6 nodes, average rooting 92% and shoot formation 94%) on combination: T-23-25°C, H-80%, Lux-5-5500, 16h. Combination: T-25-27°C, H-75%, Lux-5-5500,16h was best for medium early cultivars (5-6 nods, rooting 89% and shoot formation 90%). The perfect in vitro reproduction of medium late varieties (5-6 nodes, average rooting 87% and shoot formation 82%) was observed on the combination: T-27-29°C, H-70%, Lux-5-5500, 16h.

As it is known, for in vitro developments of early medium and late medium potato cultivars are necessary 22-26 days, but our results were obtained in 17 days. Finally, optimal in vitro condition for propagation different maturity potato cultivars was defined.

Two potato varieties: “Sebago” and “Carola” were tested for in vitro tuberization response under three different MS mediums: 1. MS+60g/l sucrose (6% MS medium) 2. MS+80g/l Sucrose (8%MS medium) 3. MS+100g/l Sucrose (10% MS medium). As a control, basal MS medium (3% MS medium) was used. The objective was to determine optimum concentration of sucrose for in vitro tuberization. Three parameters were observed in response to treatment, number, weight and diameter of microtuber. In both cultivars, among the three concentrations of sucrose, Murashige and Skoog (MS) medium supplemented with 100g/L sucrose showed a better value of microtuber number, diameter and weight than the other concentrations. Morphological characterization of micro tubers of two potato cultivars on 10% MS medium was a bit different. Accordingly, this medium gave an average value of microtuber number (3.98±0.04), microtuber diameter (9.9±0.02mm), and weight (0.09±0.003g) of microtuberian variety Sebago after 54.8±0.87 days of in vitro cultivation. Average microtuber number (2.8±0.02), microtuber diameter (9.4±0.03mm) and weight (0.087±0.002g) was showed by cultivars Carola. Microtubers were not developed on 6% and 8% MS medium (only embryonal microtubers). Finally, 10% MS medium was selected as an optimal MS medium for in vitro micro tuberization in two cultivars of potato (Sebago, Carola) after 54.8±0.87 days of in vitro cultivation.

n this study we focused on in vitro potato regeneration under different hormonal (auxin/cytokine) treatment with combination of sucrose in three potato varieties, “Nevsky, Riviera, Zefira”. Three parameters were observed in response to treatment, number of shoots development, size of shoots, and root length. In vitro tissue culture propagation of three potato cultivars (Solanum tuberosumL.) “Nevsky”, Zefira” and “Riviera” were studied on modified MS medium supplemented with hormones (IBA/BAP) concentration: MS + 30g/l sucrose (6% MS medium), 6%MS medium +1mg/l BAP + 0,05mg/l IBA and 6% MS medium +1mg/l BAP + 0,1mg/l IBA. Morphological characterization of all three in vitro potato cultivars on modified MS medium was variable depending on varieties.It was revealed that high concentration of IBA has negative effect on plants development, respectively 6% MS medium + 1mg/l BA + 0,1mg/l IBA was not optimal neither cultivars of potato. According to the results cultivars Zefira” and “Riviera” had maximum potential for in vitro rooting ( correspondingly: 82.97% and 100%) and shoots (100% and 87.34%) formation on 6% MS medium + 1mg/l BA + 0,05mg/l IBA, but “Nevsky” gave maximum development (rooting-82% and shoot formation -87%) on 6% MS medium.

Potato (Solamum Tuberosum L.) is one of the most popular crop in Georgia. The climatic conditions of Georgia enable us to produce several varieties of potato cultivars. The research goal was the development of seed production methods from apical meristem in order to get super elite seed. Three potato varieties were selected for the experiment: “Sante”, “Amoroza” and “Nevsky”. It is the first time that potato super elite seed was produced from strengthened in vitro plants (in the laboratory condition –instead of greenhouse) in Georgian regions: Akhaltsikhe and Tsalka. It was releaved that potato cultivar Nevsky characterized high elite seed Production ability (5ton), Sante showed relatively low Harvest (2ton) in Tsalka, other results were the same among Georgian two regions Akhaltsikhe and Tsalka. In this way, World-renowned elite seed making full cycle modification was performed in the conditions of Georgia: laboratory-greenhouse-open field was replaced by laboratory-laboratory (plants strengthen)-open field.

Potato is in the second place after cereals as a point of view of consumption. Nowadays Georgia has no potato seed production. To supply farmers with elite quality seed is one of the main subject in the country as there are no production companies of elite seed. Receiving elite seed full cycle modification known all over the world was done in the conditions of Georgia. Particularly the full cycle: laboratory-greenhouse-open field was replaced by laboratory (phytotrone)-laboratory(plants strengthen))-open field. Georgian farmers received the local production elite seed by our developed technology. This method will ensure the increase agriculture crops, including potato yield and the high quality planting material. Healthy seed is the guarantee of product quality.

Potato is the most widespread culture, in terms of consumptionpotato is in the second place after cereals.Nowadays Georgia has no potato seed production. Healthy seed is the guarantee of product quality. The research goal was the selection of potato species introduced from abroad and are more or less adapted to the environmental conditions of Georgia, acceptance-strengthen in vitro tube plants and their translocation in semi-open-field without greenhouse in order to get super-super elite followed by reproducing we can get potato elite seed, selected three types of potato cultivars (“Amoroza”, “Nevsky” and “Sante”), they are characterized with high productivity and rush at consumer marketReceiving elite seed full cycle modification known all over the world was done in the conditions of Georgia. Particularly the full cycle: laboratory-greenhouse-open field was replaced by laboratory (phytotrone)-laboratory(plants strengthen))-open field. Georgian farmers received the local production elite seed by our developed technology.

To avoid virus infection of seed potatoes apical meristem method is used all over the world which allows receiving virus free plants. The main problem in seed potato industry is viral contamination. Potato virus symptoms are not always revealed immediately, it depends on such factors as growth conditions, season, time of plant infection, existence of virus vectors, etc.There are number of viruses which affect the plant productivity, they can cause significant decrease in yield. In spite of diverse climatic conditions, potato is high spreading culture in mountain regions of Georgia. The main goal of the research was to study the potato viral diseases distribution in Georgia. Survey for the detection of viral agents was conducted from potato varieties; Agria, Impla, Nevsky, Marfona located in Alkalaki region. Potato cultivars were tested for 6 types of viruses: PVA,PVS, PLRV, PVY, PVM, PVX by means of Double Antibody Sandwich-Enzyme Linked Immunosorbent Assay (DAS-ELISA)using monoclonal and polyclonal antibody. The result showed that PVY and PLRV virus presence respectively: 27.8% and 18.6% in collected samples was relatively high comparing to others. PVM virus distribution was minority (2.45%) and existence of PVX, PVA and PVS was not revealed. In the same samples were found double infection particularly 8.3% of patterns were containing PVY/PLRV combination. Therefore, based on the result of our study it can be concluded that the only way to avoid reduced harvest yields is regular potato seed production sampling and testing of all stage (lab, greenhouse & open field).

In vitro plant reproduction widely used in agriculture and biotechnology and has a great advantage compared to traditional breeding methods allows to obtain get planting material in a short-term and plant reproduction can be conducted throughout the year. The present investigation was carried out to select best MS medium protocol and identify perfect hormonal/sucrose combination for three varieties of potato (Solanum tuberosum L): “Nevski”, “Riviera” and “Zefira” for their in vitro cultivation.

Potato varieties were studied on three types of MS medium: MS+30 g/l sucrose (6% MS medium), 6% MS medium +1 mg/l BAP+0.05 mg/l IBA and 6% MS medium+1 mg/l BAP+0.1 mg/l IBA. It was revealed that high concentration of IBA has negative effect on plants development, respectively 6% MS medium+1 mg/l BA+0.1 mg/l IBA was not optimal neither cultivars of potato. According to the results cultivars Zefira and Riviera had maximum potential for in vitro rooting (correspondingly:82.97% and 100%) and shoots (100% and 87.34%) formation on 6% MS medium+1 mg/l BA+0.05 mg/l IBA but Nevsky gave maximum development (rooting 82% and shoot formation 87%) on 6% MS medium. In conclusion, both hormones combination presented in experiment with 30 g/l sucrose showed optimal result on in vitro growing potato cultivars Zefira and Riviera but best in vitro cultivation of Nevsky was revealed MS medium supplemented only 30 g/l sucrose without growth hormones, probably Nevsky has ability to produce itself the amount of hormones which is necessary for its normal growing

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