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D. Pimentel (Ed.): Encyclopedia of Pest Management. Marcel Dekker, Inc., New York, Basel, 2002. 929 pp. ISBN 0-8247-0632-0

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Large numbers of wheat genotypes were grown under field conditions and screened for biotic stress tolerance and certain protective compounds. It was found that both the salicylic acid and polyamine contents of the investigated genotypes varied over a wide range, while the antioxidant enzyme activities showed a similar pattern in the different genotypes. In order to investigate stress-induced changes in salicylic acid and polyamine contents, samples were collected from plants artificially inoculated with leaf rust (Puccinia triticina), on which natural powdery mildew [Blumeria graminis (DC.) Speer f. sp. tritici Em. Marchal] infection also appeared. Biotic stress mostly resulted in elevated levels of total salicylic acid and polyamines in all the genotypes. The activities of various antioxidant enzymes showed similar changes after infection regardless of the genotype. The investigation was aimed at detecting a relationship between the level of stress tolerance and the contents of protective compounds, in particular salicylic acid and polyamines.

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Over the last two centuries the atmospheric CO2 level has exhibited a consistent rise, leading to an increase in the greenhouse effect. This level is now 35% higher than it was before the industrial revolution. On the basis of various scenarios from the Special Report on Emissions it is expected to rise from the present level of 385 ppm to 650–970 ppm by the end of the 21st century.Plant biomass and resistance of winter wheat to various powdery mildew pathotypes were investigated at normal (400 ppm) and enhanced (700 ppm) atmospheric CO2 levels in a greenhouse. Wheat cultivars Ukrainka and Mv Hombár, and 12 lines from the mapping population developed from their cross and exhibiting different level of resistance were tested.The results showed that the atmospheric CO2 level had little influence on the resistance of winter wheat to powdery mildew infections based on the percentage of leaf area covered whole plant percentage severity. In response to higher atmospheric CO2 level there was an increase in the aboveground biomass of the winter wheat genotypes tested in the present work, leading to an increase in plant height and in stem and leaf weight. However, the number of tillers and the grain yield did not increase compared with the values recorded at normal atmospheric CO2 level.

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Fifty Triticum aestivum genotypes, including winter wheat cultivars from Martonvásár, were tested for fusarium head blight (FHB) resistance under artificially inoculated conditions. Field resistance, kernel infection, and the relative yield components (test weight, thousand kernel weight and kernel weight/heads) were examined following infection with Fusarium graminearum and F. culmorum isolates. Using data from two years, a number of Martonvásár varieties with above-average resistance to FHB were identified. On the basis of field infection, AUDPC values close to those of resistance sources were calculated for the variety Mv Emese, while 67.5% of the varieties tested had values which did not differ significantly from those of the control variety Arina. The yield components examined were modified substantially by artificial FHB infection. The thousand kernel weight and test weight of the variety exhibiting the greatest degree of infection were only 21.14% and 25.58%, respectively, of the untreated control. In one case the decline in the kernel weight/head was more than 90%. The results of multivariable statistical analysis indicated that among the Hungarian wheat genotypes, Bánkúti 1201, B9086-95 (a line derived from Bánkúti 1201), Mv Emese, Martonvásári4 and Mv Táltos could be grouped with the best sources of resistance. The experimental data revealed wide genetic variability for FHB resistance in the Martonvásár breeding stock.

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Authors: L. Szunics, E. Pocsai, Lu. Szunics and G. Vida

In recent years viral diseases have become more frequent on cereals in Hungary. In the breeding nursery of the Martonvásár Institute, which contains stocks with very diverse genetic backgrounds, wheat suffered major attacks by viruses in 1972, 1976, 1980, 1981, 1982, 1986, 1990, 1996 and 1998. The winter barley plots incurred great damage in 1989 and 1990, while a large proportion of the durum wheat was destroyed in 1996. In 1982 barley yellow dwarf virus caused an epidemic in Fejér County and on many farms the damage was so great that the fields had to be ploughed up. The following nine viruses, which impose a threat to cereals, have been identified in Hungary to date: 1966: barley yellow dwarf luteovirus (BYDV), 1984: barley stripe mosaic hordeivirus (BSMV), 1985: wheat streak mosaic tritimovirus (WSMV), 1986: brome mosaic bromovirus (BMV), cocksfoot mottle sobemovirus (CfMV), 1988: wheat dwarf mastrevirus (WDV), 1989: barley yellow mosaic bymovirus (BYMV), 1990: agropyron mosaic rymovirus (AgMV) and ryegrass mosaic rymovirus (RyMV). The most frequent and widespread of these are BYDV and WDV, which are thus able to cause the greatest quantitative and qualitative damage. On the basis of six years’ data (1994–2000), neither BYDV nor WDV could be isolated from 35.7% of 1163 samples exhibiting leaf yellowing and dwarfness. This indicates that other viruses pathogenic to cereals can induce similar symptoms. Among the plants showing symptoms of virus infection, 47.3% were attacked by WDV alone, in proportions ranging from 28.8% in barley to 69.7% in triticale. The degree of infection changed from year to year: WDV was isolated from 0.0% of symptom-exhibiting plants in 1999, from 48.5% in 1997 and from 94.0% in 2000. Barley yellow dwarf virus was only isolated alone from 9.5% of the samples, while it was isolated together with wheat dwarf virus from 7.5% of the samples. Considerable differences were observed between the cereal species: only 5.6% of the durum wheat samples were infected with BYDV, while this figure was 28.1% for oats. There was also a significant year effect. In 1996 triticale was not infected, while in 2000 5.0% of the plants exhibited symptoms and in 1994 45.5% of the plants were hosts to the BYD virus. Under Hungarian conditions all five known serotypes can be found, though in different proportions depending on the cereal species and the year. The most frequent is RPV (27.4%), followed by PAV (26.9%), SGV (15.6%), MAV (15.3%) and RMV (14.8%). In samples collected from oats only the PAV serotype was found. The MAV serotype has never been isolated from triticale. The dominant serotype was RPV (60.7%) in wheat samples, SGV (36.0%) in durum wheat and RMV (29.1%) in barley.

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The breeding and cultivation of resistant wheat varieties is an effective way of controlling leaf rust ( Puccinia triticina Eriks.). The use of molecular markers facilitates the incorporation of the major leaf rust resistance genes ( Lr genes) responsible for resistance into new varieties and the pyramiding of these genes. Marker-assisted selection was used to incorporate the Lr genes currently effective in Hungary ( Lr9 , Lr24 , Lr25 , Lr29 ) into winter wheat varieties. The Lr genes were identified using STS, SCAR and RAPD markers closely linked to them. Investigations were made on how these markers could be utilised in plant breeding, and near-isogenic lines resembling the recurrent variety but each containing a different Lr gene were developed to form the initial stock for the pyramiding of resistance genes. The results indicate that the marker-assisted selection technique elaborated for resistance genes Lr24 , Lr25 and Lr29 can be applied simply and effectively in wheat breeding, while the detection of the Lr9 marker is uncertain.

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Authors: P. Szűcs, O. Veisz, G. Vida and Z. Bedő

One basic precondition for the reliable cultivation of winter durum wheat (Triticum durum Desf.) in Hungary is for the varieties to have good winter hardiness and frost resistance. Field overwintering experiments carried out in Martonvásár between 1995 and 2003 demonstrated that there was a significant difference every year between the overwintering of varieties with poor and good frost resistance, though only in two years was there a significant difference between that of varieties with medium and better frost resistance. Only a medium correlation was observed between the mean annual values of the air temperature in the winter months and the winter hardiness of the varieties, confirming that winter hardiness is influenced jointly by a number of environmental factors (e.g. cold, snow cover). In the experiments carried out on the winter hardiness dynamics of durum wheat, it was found that in milder winters even T. durum varieties which are sensitive to frost overwintered with little damage, while in the two coldest winters during the experimental period the hardiness of these varieties did not provide sufficient protection even in December, and all the plants were destroyed by January. The early spring frosts experienced in 1996 proved in these experiments that spring frosts may cause considerable damage even to durum wheat varieties with relatively good winter hardiness. Averaged over eight years, the results prove that T. durum genotypes are now available whose average state of hardening and winter hardiness are equal or better than those of winter T. aestivum varieties with moderate frost resistance.

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As in the case of other wheat diseases, adult plant resistance (APR) to powdery mildew remains effective longer than monogenic hypersensitive resistance, so the objective was to identify winter wheat genotypes with this type of resistance. Field and greenhouse tests conducted on 41 varieties and breeding lines indicated that 36 were susceptible in the seedling stage, and only five were resistant in all stages of development. It is probable that these latter genotypes contain major resistance genes. The area under the disease progress curve was the same for most of the wheat genotypes as for the APR control variety Massey, but varieties and lines with significantly better resistance were also identified. Among the genotypes in the Martonvásár breeding stock, Mv Táltos and the line Mv07-03 were found to have excellent adult plant resistance.

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Authors: C. Kuti, L. Láng, G. Gulyás, I. Karsai, K. Mészáros, G. Vida and Z. Bedő

In recent years an information system has been elaborated and constantly improved in Martonvásár, making it possible to handle the 3–4 million identification, observation, measurement, pedigree and other data generated for a total of almost 100,000 experimental plots each year. The extremely rapid development of biotechnology has made breeders interested in integrating molecular breeding methods into the conventional phenotype-pedigree system. The aim is to improve the competitiveness of breeding programmes through the intensive use of this new technology, with particular emphasis on determining how marker-assisted selection can be utilised. The present paper outlines not only a new data structure introduced to accommodate the new data elements of data categories such as gene sources, primer bank, primer combinations, markers, genes and alleles, but also data management tools and a standalone software interface to combine both molecular and phenotypic data. The integration of the molecular genomic data (GENETECH) with the information from the existing databases: pedigree (PEDIGREE), gene bank (GENEBANK) and germplasm exchange (GERMPEXCHG), ensures that biotechnological data generated at no little cost can be harnessed in ways that are important for breeders in decision-making. This is achieved through: (i) identification and centralization in uniform sources of the molecular data, and their matching with specific phenotypes, with special regard to those of importance for marker-assisted selection, (ii) integration and compliance with existing information system data, (iii) facilitation of decision-making based on the above (e.g. grouping of selection/crossing partners).

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Authors: C. Kuti, L. Láng, G. Gulyás, I. Karsai, K. Mészáros, G. Vida and Z. Bedő

The research institute in Martonvásár is one of the largest agricultural research institutes in Hungary and in Central Europe. For many years now, the accumulated data on the extensive wheat breeding stocks has been handled and analysed using programs developed in the institute. The information system that has been elaborated and constantly improved can be used for keeping records of breeding stock, for planning field and laboratory experiments, for site-plant performance evaluation, for automated data collection, for the rapid evaluation of the results and for effective management of the pedigree, seed exchange and the institute’s cereal gene bank.The demand for the storage of molecular data and their use in breeding has increased parallel with the development of new, PCR-based markers. For this reason, informatics tools (data structure and software) suited to the design of marker-assisted selection experiments and the interpretation of the results have been developed as part of the existing Martonvásár wheat breeding information system. The aim was to link molecular data to the phenotypic information already available in the database and to make the results available to wheat breeders and geneticists.The interpretation of molecular data related to specific genotypes is of assistance in clarifying the genetic background of economically important phenotypic traits, in identifying markers linked to the useful genes or agronomic traits to be found in the genomics database, and in the selection of satisfactory parental partners for breeding. Marker assisted selection coupled with traditional breeding activities enables the breeder to make plant selections based on the presence of target genes. Conventional wheat breeding with the integrated molecular component allows breeders to more accurately and efficiently select defined sets of genes in segregating generations.The molecular data are stored in a relational database, the central element of which is the [DNASource] entity. This is used to collect and store information on gene sources arising during breeding. It is therefore linked both to the phenotypic data stored in the traditional breeding system (measurements, observations, laboratory data) and to the component parts of the new, molecular data structure ([PrimerBank], [Marker], [Allele] and [Gene]).

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