Search Results

You are looking at 1 - 10 of 34 items for

  • Author or Editor: Z. Varga x
Clear All Modify Search

The effects of UV-C radiation on the germination rate and fungal contamination of tall fescue seeds were investigated. Samples from the same seed lot were irradiated in two different ways in two consecutive years. The seeds were irradiated with a Hg vapour lamp using different doses. In the first trial one side of the seeds was irradiated, while in the second trial a mirror was used to irradiate the whole seed surface. The results showed that various doses of UV-C irradiation had an effect on the germination rate, but there were no significant differences in germination percentage between the treatments. Differences in fungal contamination rates were observed when the seeds were irradiated on all sides. The presence of 21 fungal genera was identified on the seeds, the saprotrophic fungi Alternaria, Rhizopus and Penicillium being dominant.

Restricted access
Acta Agronomica Hungarica
Authors: Z. Varga-Haszonits, E. Enzsölné Gerencsér, Z. Lantos and Z. Varga

The temporal and spatial variability of soil moisture, evapotranspiration and water use were investigated for winter barley. Evaluations were carried out on a database containing meteorological and yield data from 15 stations. The spatial distribution of soil moisture, evapotranspiration and water use efficiency (WUE) was evaluated from 1951 to 2000 and the moisture conditions during the growth period of winter barley were investigated. The water supply was found to be favourable, since the average values of soil moisture remained above the lower limit of favourable water content throughout the growth period, except for September–December and May–June. The actual evapotranspiration tended to be close to the potential evapotranspiration, so the water supplies were favourable throughout the vegetation period. The calculated values of WUE showed an increasing trend from 1960 to 1990, but the lower level of agricultural inputs caused a decline after 1990. The average values of WUE varied between 0.87 and 1.09 g/kg in different counties, with higher values in the northern part of the Great Hungarian Plain. The potential yield of winter barley can be calculated from the maximum value of WUE. Except in the cooler northern and western parts of the country, the potential yield of winter barley, based on the water supply, could exceed 10 t/ha.

Restricted access

A better understanding of the relationships between insects and microfungi could help to identify the unknown factors reducing yields in maize. As the first step in current research, the aim was to isolate the microfungal species that can be found in the larval cavity of the European corn borer ( Ostrinia nubilalis Hbn. Lepidoptera. Pyraustidae ) (ECB), one of the most important insect pests of maize. In this way, the scale of potential phytopathogens spread by intermediate hosts could be reduced.Fifty stalk sections damaged by ECB larvae were collected in autumn and fifty in spring on a 20-hectare plot in Ráksi (Somogy county). These were placed in wet chambers and incubated at room temperature under natural light. Identification was done from a pure culture inoculated into potato dextrose agar. Twenty-one species from 14 fungus genera were identified, the majority of which were mitosporic fungi. Species belonging to the Fusarium, Acremoniella and Cladosporium genera were predominant. Most of the species were saprotrophic, though some phytopathogenic species ( Gibberella, Colletotrichum, Nigrospora and Fusarium ) were also identified. The number of genera and the incidence of fungi were much higher in spring samples than in autumn ones, except for Fusarium , where incidence was lower in spring. It was found that failing to harvest the maize significantly enhanced the spread of several fungus species, especially phytopathogenic species, the following year, thereby serving as a source of infection.

Restricted access

The spatio-temporal patterns of the seismicity are shown. The earthquake occurrence is connected to the strain rate on the basis of Kostrov (1974) equation. It is shown that in the Pannonian Basin the seismic rates are 10-7-10-6. This values were derived from the local earthquake catalogues of the area of Komárom, Dunaharaszti (near Budapest) and Kecskemét.  It is shown that the earthquake occurrence in Hungary  has a well expressed diurnal periodicity.  Similar phenomenon was detected in the case of earthquakes of all Europe and in Turkey in case of weak (M L = 3.0) seismic events.

Restricted access

For Lotka-Volterra population systems, a general model of state monitoring is presented. The model includes time-dependent environmental effects or direct human intervention (treatment) as control functions and, instead of the whole state vector, the densities of certain indicator species (distinguished or lumped together) are observed. Mathematical systems theory offers a sufficient condition for local observability in such systems. The latter means that, based on the above (dynamic) partial observation, the state of the population can be recovered, at least near equilibrium. The application of this sufficient condition is illustrated by three-species examples such as a one-predator two-prey system and a simple food chain.

Restricted access

The paper deals with two bee species collecting nectar from two plant species. It is assumed that the nectar stock is reduced but not exhausted by the nectar collection, each individual's pay-off depends linearly on its own foraging strategy (i.e., on the probability of a visit to a plant species) and on the average strategies of both species. For the corresponding matrix game model, it is shown that evolutionary stability of a totally mixed equilibrium foraging strategy pair is only determined by the efficiency parameters of nectar collection. The latter parameters depend on morphological characteristics of all involved species, determined by the long-term evolutionary processes. The evolutionarily stable foraging strategy is locally asymptotically stable with respect to the corresponding replicator dynamics.

Restricted access

Winter wheat ( Triticum aestivum L.) cultivars may differ in grain quality responses to nitrogen (N) and fungicide applications, the two most important management inputs in the temperate climates of Europe. Limited information is available on N and fungicide effects on wheat quality in Croatia, where the wheat crop is widely grown under low N inputs without fungicide application. Field experiments were conducted during three years to evaluate the effects of fungicide (tebuconazol applied around heading) and two N fertilization rates on the grain quality of six widely grown winter wheat cultivars. Most cultivars failed to achieve the minimum breadmaking standards at a low N rate because of low protein content (103 g kg −1 ), Zeleny sedimentation (22.2 cm 3 ) and wet gluten (201 g kg −1 ). High N fertilization significantly increased these quality traits in all cultivars (an average of 21% for grain protein, 58% for Zeleny sedimentation and 40% for wet gluten). However, some cultivars with low genetic potential for accumulating grain protein failed to reach the breadmaking quality even at a high N rate when the N availability in the soil was limited by drought. Significant cultivar × N interactions existed for all grain quality traits, but were mainly associated with differences in the magnitude of the responses and less with the ranks. Five cultivars consistently showed increased falling number as the N rate rose, but these cultivar-specific responses to N fertilization were of much lesser magnitude than those across years. Fungicide application showed no effect on grain protein. Zeleny sedimentation, wet gluten or gluten index in all six cultivars tested, whereas one cultivar consistently showed decreased falling number after fungicide use. Only the hectolitre weights increased following fungicide application, especially for disease-susceptible cultivars at the high N rate. Thus, high N fertilization resulted in cultivar-dependent increases in protein content, Zeleny sedimentation, wet gluten and falling number, whereas fungicide application had no effect on grain quality except improved hectolitre weights.

Restricted access

Abstract  

A rapid and simple sample preparation method for plutonium determination in environmental samples by inductively coupled plasma sector field mass spectrometry (ICP-SFMS) and alpha-spectrometry is described. The developed procedure involves a selective CaF2 co-precipitation for preconcentration followed by extraction chromatographic separation. The proposed method effectively eliminates the possible interferences in mass spectrometric analysis and also removes interfering radionuclides that may disturb alpha-spectrometric measurement. For 239Pu, 240Pu and 241Pu limits of detection of 9.0 fg·g−1 (0.021 mBq), 1.7 fg·g−1 (0.014 mBq) and 3.1 fg·g−1 (11.9 mBq) were achieved by ICP-SFMS, respectively, and 0.02 mBq by alpha-spectrometry. Results of certified reference materials agreed well with the recommended values.

Restricted access
Acta Biologica Hungarica
Authors: Nóra Faragó, Ágnes Zvara, Z. Varga, P. Ferdinandy and L. Puskás

Micro RNAs (miRNA) are an abundant class of small RNAs that regulate the stability and translation of cognate mRNAs. MiRNAs are potential diagnostic markers, moreover, they play an essential role in the development of various heart disesases. In case of limited tissue material, such as, e.g. human biopsies, purification of miRNAs with sufficient yield is critical. Reproducible expression analysis of miRNAs is highly dependent on the quality of the RNA, which is often difficult to achieve from fibrous tissue such as the heart. Several companies developed general purification kits for miRNAs, however, none of them are specialized to fibrotic tissues. Here we describe an optimized miRNA purification protocol that results in high miRNA yield as compared to other methods including trizol-based and column-based protocols. By using our improved protocol, miRNA obtained from heart tissue gave more reproducible results in QRT-PCR analysis and obtained more significant calls (172 vs. 118) during DNA microarray analysis when compared to the commercially available kit. In addition to the heart tissue, the present protocol can be applied to other fibrotic tissues, such as lung or skeletal muscle to isolate high-purity miRNA.

Restricted access
Acta Alimentaria
Authors: V. Szente, O. Szigeti, Zs. Polereczki, Á. Varga and Z. Szakály

In Hungary, organic food market has both demand and supply oriented aspects: several times not necessary products are distributed, while the selection and volume of certain products are not satisfactory. Thus, our aim was to develop a coordinated benchmark strategy to increase the trade of organic products. To get more details on the Hungarian organic milk market, we conducted professional deep interviews and simultaneously applied the “mystery shopping” method. Nowadays, the market of organic milk and dairy products is slowly increasing in Hungary, however, there is no available statistical data. In the selection there are mostly Hungarian originated products, but some yoghurt, milk, and butter assortments are imported. Partial responsibility belongs to small sale shops’ habit of risk-avoidance. Without a proper selection of products, stores are unable to satisfy consumers’ needs; thus they focus on pushing certain products to increase demand. According to our results, ‘low price category’, ‘local/regional product’, and ‘prestige product’ strategies with attached in-store marketing elements are able to reverse the effects of an unfavourable marketing process.

Restricted access