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Phytoplasma diseases of grapevine and the possible measures to control them
37-43.Views:329Phytoplasmas are a special group of phloem-living pathogens in several plant species. Grapevine yellows (GY) is a term for phytoplasma diseases occurring on Vitis vinifera and inducing the same or very similar symptoms and causing severe losses worldwide. Flavescence Dorée (16SrV) phytoplasma (FD, species name: ‘Candidatus Phytoplasma vitis’) is considered a quarantine pest in several countries due to its epidemic character and high economic loss it provokes. The leafhopper Scaphoideus titanus is the univoltine and monophagous vector of FD. Bois noir disease caused by stolbur (16SrXII-A) phytoplasma (species name: ‘Candidatus Phytoplasma solani’) is described under different disease names in different countries. Hyalesthes obsoletus (Cixiidae) is the only proved polyphagous vector of BN. However, distribution of BN disease is increasing also on those areas where H. obsoletus is not prevalent or only in a very low number. Therefore the presence of other vectors cannot be concluded. The ‘Tuf-a’ type Stolbur phytoplasma is associated with stinging nettle (Urtica dioica) and the tuf-b type one to field bindweed (Convolvulus arvensis). There are only preventive control measures against phytoplasmas: the use of pathogen-free propagating material, hot water treatment of propagating material, as well as control of vectors and weeds. S. titanus can be efficiently controlled by insecticide treatments. However, in case of H. obsoletus, insecticides are not effective due to the biological characters and feeding habits of the vector.Weed control can reduce H. obsoletus specimen and their abundance to a certain extent. Extensive research is needed on wild hosts of GY phytoplasmas especially on BN phytoplasma and its vectors to the better understanding of their epidemiology.
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Primers designed for the detection of grapevine pathogens spreading with propagating material by quantitative real-time PCR
21-30.Views:291Several grapevine pathogens are disseminated by propagating material as systemic, but latent infections. Their detection and identification have a basic importance in the production and handling of propagating stocks. Thus several sensitive and reliable diagnostic protocols mostly based on molecular techniques have been developed. Of these methods quantitative real-time PCR (q-PCR) has recently got an emerging importance. Here we collected primer data for the detection and identification of grapevine pathogens which are important in the production of propagating stocks by q-PCR. Additional novel techniques that use DNA amplification, hybridization and sequencing are also briefly reviewed.
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Conventional PCR primers for the detection of grapevine pathogens disseminated by propagating material
69-80.Views:307Polymerase chain reaction driven by sequence specific primers has become the most widely used diagnostic method to detect and identify plant pathogens. The sensitive and cost-effective pathogen detection is exceptionally important in the production of propagating material. In this paper we have collected primer sequence data from the literature for the detection of the most important grapevine pathogens disseminated by propagating stocks by conventional polymerase chain reaction. Basic protocols to obtain template nucleic acids have also been briefly rewieved.
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Certification programme for production of virus-free propagating material of grapevine and its results in Hungary
39-43.Views:172In Hungary, detection of virus and virus-like diseases of grapevine began in 1960's at the Research Institute for Viticulture and Enology by János Lehoczky and his colleagues. At present, sixteen virus and virus-like diseases of Vitis vinifera are known to occur in Hungary.
Regular virological screening of grapevine varieties started in 1972. The present system of screening (visual selection, indexing, ELISA) has been established using methods with continuous improvement according to recommendations of international organizations.
In the first year symptomless grapevine plants are selected and marked during surveys carried out twice in the vegetation period: at about flowering and in the second half of September. At the first selection time plants are sampled for ELISA.
In the spring of the second year, overwintered canes are checked by woody indexing on 8 indicator species in the field.
In the third and fourth years the nursery is evaluated twice again. At the end, the marked grapevine plants, giving negative results on all indicators in every case, are considered virus-free.
In autumn of the fourth year, the virus-free material is planted out under screenhouse and also in a special mother block (nuclear stock) for maintenance and propagation.
Mother blocks of virus-free scion varieties have been established on 2 ha and those of rootstock varieties on 0.5 ha planted with the following number of varieties included in the national list: 71 European scion — and 12 rootstock varieties or variety candidates/clones. It is necessary to increase the area of Pre-base, Base and Certified stocks exclusively with tested virus-free (clean) material.
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A complex system for the production of pathogen-free grapevine propagating material
59-62.Views:248The use of pathogen-free planting stock for new vineyard establishment is a key component in the maintenance and expansion of vine and quality table grape production. The success of the necessary changes in the structure of the grape industry is forced by the globalization process, the climate change, the rediscovery of autochton varieties as well as breeding of new tolerant and resistant varieties. The renewal of vineyards largely depend on the availability of planting stocks. Serbia and Hungary found a common interest in establishing pathogen-free stock materials from newly breed resistant varieties and clonal selections of varieties which are traditional in the Serbian-Hungarian border area. During a cross-border cooperation program a complex system for the production of pathogen-free grapevine propagating material was established. Using heat therapy, in vitro shoot tip culture and traditional and molecular diagnostic techniques new pathogen-free stock materials were established from 26 varieties. They have been or will be tested for the presence of most important grapevine viruses, phytoplasmas, as well as bacterial and fungal pathogens. The complex system applying green grafting for indexing on grapevine indicators can shorten the duration of the procedure from 4 years to two-three years.
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In vitro multiplication and hardening of grapevine plants in aeriated media
15-18.Views:218In vitro cultures have widely been used in horticulture for rapid multiplication of new varieties and clones as well as to produce pathogen-free stock material. To improve efficient hardening and transfer in vitro grown grapevine plants were multiplied by cutting them into single-node internodes with the whole leaf. Microcuttings including the shoot tips were rooted in granulated perlite moisted with tapwater under sterile conditions. After 2-3 weeks the rooted microcuttings were supplied by nutrients and hardened by gradual opening and finally by complete removal of the lids of jars or plastic boxes used for growth. Using this method microcuttings of Vitis vinifera cvs. „Chardonnay", „Cabernet franc", „Riesling" and „Sauvignon blanc" and the rootstock varieties Vitis riparia x Vitis cinerea cv. „Barrier" and Vitis berlandieri x Vitis rupestris cv. „Richter 110" formed new roots and shoots and 100% of the tested plants survived the acclimatization procedure. Similar results were obtained when perlite was replaced with rockwool-, or pit-pot blocks. This method may highly increase the efficiency of producing pathogen-free propagating material and new transgenic lines.
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Nutrition content of spent mushroom compost before and after utilization in vegetable forcing experiments
53-55.Views:165The Spent mushroom compost means the remained soil without sporophores after the productive.period. The leftover can't be used for mushroom growing again (Gy6r1i, 2001). Unfortunately spent musnroom compost still has bad judgment, as it would be garbage, but on the contrary it is a significant and valuable material, which is full of organic residue, a perfect soil structure improver, nutrition supplement and propagating medium. In our experiment we took the following mediums: control material with 50% flat moor peat and 50% high moor peat (Novobalt) content, 100% spent compost, 50% spent compost and 50% control medium, 25% spent compost and 75% control medium. On the day of plantation and after the forcing experiment we took sample from the control medium and from all mixtures.
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Perspectives and tasks in horticultural production
11-22.Views:220The work summarizes the prospective conceptions of all the five horticultural branches. These branches (vegetable, fruit, grape and wine, herb and ornamental plant production) with the production of propagating material together amount to round 30-35% of the total value of the entire plant production. The performance of horticultural branches declined significantly because of privatisation and lack of capital. The accession to the EU urges the development of modernization and competitiveness, therefore the state subsidies are indispensable.
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Bacterial diseases of grapevine
45-49.Views:420Grapevines are affected by three major bacterial diseases worldwide, such as bacterial blight (Xylophilus ampelinus), Pierce’s disease (Xylella fastidiosa) and crown gall (Agrobacterium vitis). These bacteria grow in the vascular system of their host, thus they invade and colonize the whole plant, independently on symptom development. Latently infected propagating material is a major factor in their spreading. Therefore the use of bacteria-free planting stock has a basic importance in viticulture. Today several innovative diagnostic methods, mostly based on polymerase chain reaction, are available to detect and identify bacterial pathogens of grapevines. For production of bacteria-free plants, the use hot water treatment followed by establishment of in vitro shoot tip cultures is proposed.