Szerző szerinti böngészés "Bisztray, Gy. D."
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Tétel Szabadon hozzáférhető Actual state of research concerning vitamin C as reflected in the literature (Review article)(2004-03-16) Domokos-Szabolcsy, É.; Holb, I. J.; Veres, Zs.; Bisztray, Gy. D.; Fári, M. G.Vitamin C (L-ascorbic acid) being essential for many living organisms, including man, became once more into the focus of interests because of its numerous physiological effects. Its anti-scurvy and anti-oxidant properties have already been recognised since long in the human body, but it turned out gradually that it has many other functions. In plants, its primary importance is defense against the photo-oxidative stress. The present review is intended to reveal some details of the artificial synthesis of vitamin C. Emphasis is put on the metabolism of L-ascorbic acid in higher plants. Biosynthetic processes, translocation and accumulation are discussed in detail on the basis of recent results published in the scientific literature.Tétel Szabadon hozzáférhető A complex system for the production of pathogen-free grapevine propagating material(2011-06-25) Bisztray, Gy. D.; Lázár, J.; Szegedi, E.; Varga, G.; Nagy, B.; Hajdu, E.The 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.Tétel Szabadon hozzáférhető The effect of cluster thinning, cluster tipping, cluster shredding and defoliation at the flowering on the vegetative and generative vine performance from Kékfrankos Cv.(2012-04-25) Fazekas, I.; Göblyös, J.; Bisztray, Gy. D.; Zanathy, G.The cluster thinning is a method of the yield regulation.With the removal one part of the clusters, the yield pro leaf area will be lower, hereby the grape and wine quality will be improved. The regulation of the yield can lead to further advantages: the ratio of the vegetative and generative performance of the vines will improve, the condition of the plants will better, the number of the physiological diseases can be reduced and the growth of the shoots and roots can be promoted. The grape growers make the cluster thinning almost exclusive by creating one cluster shoots. Usually the upper clusters are removed, because the sugar content of these second or third clusters will be lower. The cluster thinning is an easy task, can be done without special skills. It is an effective method improving wine quality, but its use can lead to other problems. The grapes try to compensate the removed clusters. Therefore the clusters will be bigger and thicker, but more sensitive to bunch rot. Moreover the treatment is expensive, because it needs manual work. It is worth to get acquainted and try the new yield regulation methods, which can help to avoid the occurring problems. Our aim is to show the results of our experiment, which was carried out in Eger, examining the red grape cultivar Kékfrankos. During our 4 years long experiment we compared the effects of cluster thinning, cluster shredding, cluster tipping and defoliation at the flowering, on the vegetative and generative vine performance.Tétel Szabadon hozzáférhető Examinations of 600-year-old seeds by means of archaeobotanical and genetical methods(2004-11-15) Bacsó, R.; Facsar, G.; Gyulai, F.; Bisztray, Gy. D.; Velich, I.About 600-year-old plant seeds were discovered in a well of a mediaeval cellar in the course of an excavation in Budapest. After the archaeobotanic purification seed of 16 species were found in large quantities. Seeds preserved in the best state were selected from each group. The existence of endosperm was analysed in these subfossils, which turned to be successful mainly in the case of grapes (Vitis vinifera) and cornels (Cornus mas). Seeds of these two species contained the most endosperm and remains of the embryo. DNA was extracted with the help of DNEasy Plant Mini Kit and analysed by RAPD-PCR method. The amplification of DNA extracted from cornel seeds resulted in detecting a 1500 by fragment, which makes the comparison of these samples with present-day cornels possible.Tétel Szabadon hozzáférhető Microsatellite based identification of grapevine cultivars traditional in Hungary and in the Carpathian Basin(2005-10-11) Bisztray, Gy. D.; Deák, T.; Eisenheld, C.; Pedryc, A.; Balogh, I.; Regner, F.Grapevine cultivars and clones traditional in Hungary and in the Carpathian Basin are maintained in the genetic collection of the Corvinus University of Budapest. Mostly ancient varieties and clones were genotyped using microsatellite loci. The investigated 6 loci were sufficient to distinguish all cultivars. Some clones could also be separated based mostly on the variable VVS2 loci. For 17 out of the 31 investigated cultivars this is the first report on characterization of the polymorphism of the allele lengths by microsatellite markers on loci: VVS2, VVMD7, VVMD27, vrZAG62.Tétel Szabadon hozzáférhető Molecular diversity of Hungarian melon varieties revealed by RAPD markers(2002-10-16) Bába, E.; Zarka, V.; Deák, T.; Pedryc, A.; Velich, I.; Bisztray, Gy. D.RAPD markers were used to reveal genetic diversity between nine varieties of Cucumis melo L. and to identify the studied varieties. Of the 60 primers tested 12 primers produced polymorph patterns. A set of 4 primers was sufficient for distinction the nine investigated melon varieties.Tétel Szabadon hozzáférhető Old Hungarian grapevine cultivars and their relations characterized with microsatellite markers(2008-12-08) Bodor, P.; Varga, Zs.; Deák, T.; Pedryc, A.; Bisztray, Gy. D.Thirty-one old Hungarian grapevine (Vitis vinifera L.) cultivars were investigated on 7 microsatellite loci to characterize them, to separate the cultivars from synonym names, and to confirm parent-offspring connections. Conculta (group of cultivars or bud sports) members, such as `Goher' and Tajor' representatives, were studied to find a suitable locus for the separation. Synonyms, conculta members, subcultivars and clones of Turmine, which was the most important cultivar of Tokaj, were also analyzed to separate the members of the different taxonomic levels. Pedigree of 'Kiralyleanyka' was examined to find the missing ancestor, because the parent-offspring connection between the natural hybrid and `Koverszolo' is questionable.Tétel Szabadon hozzáférhető RAPD analysis of grapevine hybrids and cultivars(2004-11-15) Halász, J.; Korbuly, J.; Deák, T.; Bisztray, Gy. D.Utilization of the Randomly Amplified Polymorphic DNA (RAPD) technique as a molecular marker was tested to investigate the relationships between some representative grapevine cultivars and hybrids established at the Department of Genetics and Plant Breeding (CUB), to distinguish clones as well as to characterize various hybrids between species or cultivars and their parents. Vitis vinifera cultivars were easily and successfully distinguished by the RAPD technique and they were grouped according to the traditional taxonomic classification. RAPD patterns of the examined Pinot gris clones proved to be completely identical. Number of generations was reflected by the value of genetic distance of the examined hybrids. Genetic identity of parents and their offsprings was influenced by the selection applied in the process of plant breeding. Parental phenotypic and morphologic characteristics showed high degree of segregation in hybrids, but RAPD analysis revealed that their genetic similarity is considerable. The three Vitis anntrensis clones were properly discriminated from every cultivar and hybrid of Vitis vinifera, i.e. hybrids are much closer to the cultivated grapevine than to V. anzurensis due to the phenotypic selection carried out during the life-cycle of one or two generations.Tétel Szabadon hozzáférhető Virus and virus-like diseases of grapevine in Hungary(2011-06-25) Lázár, J.; Bisztray, Gy. D.Viruses and viroids are submicroscopic infectious particles which can cause disease symptoms on grapevine. These parasites are depending completely on the energy metabolism of the plant cell. To enter the host cell plant viruses depend on injuries or on transmission via invertebrates (insects, nematodes, etc.). Viruses are classified by many characters including particle morphology, host range and information content of the genome. At present about 70 viruses including 7 viroids infecting grapevine are known. In single or mixed infections they are potentially detrimental to the quality and quantity of grape production in any growing area of the world. Some viruses can cause severe economic damage in vineyards. In Hungary many important viruses and viroids have been detected in grape. This review summarises characteristics of viruses and the results of detection and characterization of virus and virus like diseases of grapevine in Hungary. The identification of the causal agent, its transmission, geographical distribution and the development of the diagnostic methods are also discussed.