Sharka disease is one of the most devastating plant epidemics of Prunus species, caused by plum pox virus (PPV). The viral infection affects the fruits by weight-loss and degradation of quality properties. Breeding of resistant rootstocks and cultivars is one of the most effective disease control methods. PPV determines the peach production all over the world. On the world's fruit production list peach is in the sixth, in the Mediterranean region in the fourth place. In this study new data were shown about PPV susceptibility of commonly used rootstock-scion combinations from Hungary. Reverse transcription PCR (RT-PCR) analysis was conducted on the samples from a commercial orchard; the results were evaluated by chi-square test and binary logistic regression. Four rootstock ('GF677', 'PeMa', 'Cadaman' and almond seedlings) and three scion cultivars (Prunus persicae 'Michelini', 'Babygold 6' and 'Cresthaven') were included in this experiment. The rootstocks did not show any significant differences in regard to the resistance of the virus infection (40-50%), but in case of scions, strong significant relations were observed. In case of the combinations there were results in both directions; tolerant and susceptible combinations were observed as well.

In the concerned region, such as Hungary Plum pox virus (PPV) causes the most serious yield loss in the stone fruit orchards. A survey of sharka disease was conducted in the north-Hungarian border region from 2010 to 2012. The main goals of the survey were to isolate the virus, to map the spreading and the actual status, to identify the PPV strains and inform the orchard owners and manufacturers about the results of the study. This survey was a part of the Hungary-Slovakia Cross-Border Co-operation Programme 2007-2012. Nearly 250 leaf samples were taken from 51 different settlements of the northern counties from stone fruit orchards, home gardens and natural environment, showing the symptoms of PPV. The surveyed species were plum, apricot, peach, sweet and sour cherry, and blackthorn. To identify the strains the following molecular methods were used: conventional RT-PCR with strain-specific primers, RT-PCR followed by RFLP analysis using EcoRI, DdeI and EcoRV restriction enzymes in the 3'P3-6K1-5'CI genomic region and RT-PCR followed by sequence analysis in the formerly mentioned region. The results show that the dominant strains were PPV-Rec in the central and PPV-D in the eastern region, but PPV-M was also identified. The apricot and peach orchards were less infected than plum orchards in the northern counties of Hungary. A suspected triple-mixed infection (M, D and Rec) is under further studies. After the survey a map was prepared, the dominant isolates, the infection rate, the host plants and the type of the sample collection places were marked. From the results a bilingual booklet was also published with the great help of the Slovak partners, for producers and orchard owners including all important knowledge about the virus and the disease prevention.

The GOCE satellite observes gravity gradients with unprecedented accuracy and resolution. The GOCE observations are reliable within a well-defined measurement bandwidth. In this study, different finite and infinite impulse response filters have been designed to obtain the demanded pass. Exhaustive time and frequency domain investigations prove that the proposed infinite impulse response filter can be a real competitor of the existing solution of the filtering problem.

The forthcoming GOCE mission will produce gravity gradient data at satellite altitude and consequently contribute to the more accurate determination of the gravity field. There are different data processing strategies in order to obtain updated gravity field information from these measurements, but most of them are based on the spherical harmonic expansion of the gravity field. An alternative approach would be the direct use of the GOCE data in the space domain. In this case we need formulas for transferring gravity gradients and other gravity field information in spherical approximation between different height levels. The well known upward/downward continuation problem of second vertical gravity gradients has been already solved. In this paper we discuss formulas for the other gravity gradients. The proposed approach is to use these gravity gradients in two combinations. The corresponding formulas are discussed and some conclusions on their practical use are drawn.

One promising method for the external validation and calibration of the upcoming GOCE satellite mission data is the use of ground gravity field data continued upward to satellite altitude. There is a unique situation for Hungary in this respect since surface gravity gradients are available at 20143 points over an approximately 48700 km(2) area, measured by the classical Eotvos torsion balance. The concept of this contribution is to test the usability of these point gravity gradient observations for upward continuation to the GOCE satellite orbit in combination with different geopotential models and other gravity field information.The computations are based on the least squares collocation method and the direct numerical integration of the torsion balance data. For the latter method, the spectral combination technique and the classical integration kernels are considered. Furthermore, various other data sources, such as the T-ZZ gravity gradients based on the gravity and terrain data collected within the frame of the European Geoid Project, are utilized for comparisons.Besides the comparisons between the different satellite gravity gradient computations, an error analysis of the results is presented.

The Geodetic Institute of the University of Karlsruhe and the Department of Geodesy and Surveying of the Budapest University of Technology and Economics have been cooperating for 30 years in the field of deformation measurements and analysis. One of the common projects in this cooperation is related to the network of Soskut which has been established to detect surface motions in the vicinity of a geological fracture. In the beginning terrestrial measurements have been carried out, while in recent years common GPS campaigns were organized in order to investigate the potential of the GPS technology in deformation measurements and analysis. The paper describes the development and the actual results of the joint project and points out the progress in methodology.

The unique radio astronomical technique of Space Very Long Baseline Interferometry (SVLBI) is an extension of the ground-based VLBI into the space. It has some important potential applications in geodesy and geodynamics, including the definition, practical realization, and interconnection of different reference frames, determining the geocentric positions of VLBI stations, estimation of the gravity field of the Earth, and satellite orbit determination using the delay and delay rate observables. With the launching of the first SVLBI satellite of the VLBI Space Observatory Programme (VSOP) of Japan, in February 1997, this technique has become a reality. An international team of scientists, working under the auspices of the FOMI Satellite Geodetic Observatory, Hungary, has designed the GEDEX, for the purpose of exploring the feasibility of the geodetic applications of SVLBI.A brief description of the SVLBI technique and references to the significant theoretical developments in the field of geodetic SVLBI are provided, followed by an over-view of salient features of the Highly Advanced Laboratory for Communications and Astronomy (HALCA), the orbital component of the VSOP mission. The state of the art and the projected developments in this field are summarised. The various aspects of GEDEX, including the objectives, the tasks involved, the scope of the experiment, the software development, the data formats and recent results of data pre-processing and test data analysis are discussed. A test VSOP data set has been pre-processed and analysed. Preliminary results show that the SVLBI delay residuals are at the level of a few meters.Conclusions drawn, based upon the experience gained in this project, and recommendations for future work are presented. The major practical problems with HALCA data for geodetic use include the single observing frequency, the limited bandwidth and sensitivity, the unreliable instrumental phase-cal data, the poor sky coverage and the sparse co-observing array of ground-based VLBI telescopes.

Two test areas with different characteristics of the terrain were selected in Hungary to model the gravity field. We have used point gravity gradients, their terrain effects and geopotential information to model geoid heights by numerical integration using kernel functions for specific gradient and curvature combinations which arise from the solution of the corresponding overdetermined geodetic boundary value problem. The truncation characteristics of these kernel functions were also taken into account. We have compared our results with the collocation solution as well.

Some steps were taken recently for Hungary aiming at the determination of geoid heights with a cm-accuracy. The present HGTUB98 gravimetric solution was based on terrestrial gravity data, height data and the EGM96 geopotential model; and was computed with the 1D Spherical FFT method, The gravity data were used in the area 45.5 degrees < phi less than or equal to 49 degrees, 16 degrees less than or equal to lambda less than or equal to 23 degrees, the resolution of the grid was 30 " x 50 ". The DTM used had a resolution of 1 km x 1 km.Our solution was evaluated using GPS/levelling data at 340 and 308 points respectively and at 138 vertical deflection points. We have compared our solution to the European EGG97 geoid solution, the gravimetric solution HGR97B developed by A. Kenyeres and the litospheric geoid solution by G. Papp. We have correlated our recent HGTUB98 solution to the Moho model of Central Europe. The comparison with GPS/levelling yielded respectively an accuracy of +/-8.7 cm and +/-4.4 cm (in terms of standard deviation) when a linear trend was removed. The comparison of the 1D planar FFT solution for the deflections of the vertical with 138 astrogeodetic deflections yielded an accuracy tin terms of standard deviation) of +/-0.62 " and +/-0.52 " for xi and eta, respectively. (C) 2000 Elsevier Science Ltd. All rights reserved.

After a break of ten years, the work on the United European Levelling Network (UELN) resumed in 1994 under the name UELN-95. The objectives of the LJELN-95 project are to establish an unified vertical datum for Europe at the one decimeter level with the simultaneous enlargement of UELN as far as possible to include Central and Eastern European countries. More than 3000 nodal points were adjusted linked to the reference point of LTELN-73 (gauge Amsterdam). The new heights in the system UELN-95/98 are available for more than 20 participating countries.

Different local gravimetric geoid solutions were carried out in Hungary and the surrounding continental area. These solutions were based on terrestrial gravity data and height data using as a reference surface the EGM96 geopotential model. The gravity data used in the area 45.5° < o < 49°, 16° < λ < 23° were finally gridded on a 1.5 x 2.5' geographical grid. These included more dense gravity data with respect to a previous gravimetric solution for Romania and Yugoslavia. The height data were available on a 1km x 1km grid. The methods used were the spherical 1D Fast Fourier Transform (FFT) method and the Fast Collocation (FCOL) procedure. In order to assess the accuracy of the computed geoid heights we compared them with 43 Hungarian GPS/leveling stations belonging to the EUREF89 network. The statistical results of the derived differences give an accuracy close to 12 cm in terms of standard deviation, which decreases to 8 cm after subtracting a linear trend and bias model. Excluding 14 GPS stations located at the borders of Hungary the aforementioned accuracies reached the level of 7 cm and 6 cm, respectively. Moreover, we have compared our geoid solution in the entire test area with the European geoid EGG97 and found a standard deviation of differences close to 41 cm and 20 cm before and after subtracting a linear trend and bias model. In a last numerical experiment we computed geoid heights by 1D FFT using different cap sizes for the gravity data. The geoid height results were similar and no significant improvement has been achieved.

contribution to a unique European height datum

The aim of the GEDEX, which is being designed by an international team of scientists, is to explore the feasibility of Geodetic & Geodynamic applications of Space VLBI. In this paper, the outline of this experiment has been presented. A brief description of the Space VLBI technique has been provided, followed by a summary of the significant theoretical developments. Salient features of the VSOP mission. and an overview of the various aspects of GEDEX have been presented. The state of the art of software for Geodetic SVLBI has been outlined, and the different steps in software development for the GEDEX have been described in detail. Conclusions drawn from the work done so far, and recommendations for future work have been presented.

Currently the European Geoid Project is on-going aimed at the determination of a Precise European Reference Geoid [Torge, 1992; Denker and Torge, 1993]. In Hungary we are strongly interested in the success of this effort toward a new European quasigeoid solution improved in spatial resolution and accuracy. Therefore appropriate gravity data and elevations from Hungary have been made available for use in the computations. In exchange the resulting geoid solution for the area of Hungary will be provided. This geoid surface will be very important for a check of the individual local quasigeoid solutions determined by Hungarian institutions.

In the next decade — the 90-es — dedicated radio telescopes will be launched into Earth orbit and will be integrated in the ground based Very Long Baseline Interferometry (VLBI) networks. Space-VLBI an emerging new observational technique will be with us.