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  • Author or Editor: L. Nagy x
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Reliable small-plot experiments play an important role in determining the value of hybrids, but the results of large-plot experiments, which give a better reflection of conditions and technologies, are needed to obtain reliable information on which hybrids can be produced most economically under specific cultivation conditions. Within the framework of the National Research Development Programme, large-scale tests are underway on new Hungarian maize hybrids, to promote the selection, introduction and propagation of the most economical hybrids for specific regions, ecological conditions and technological standards. The tests included hybrids Sze SC 271 (FAO 290), Dáma (FAO 300) and Mv 277 (FAO 320) from the very early maturity group, Sze SC 352 (FAO 340), Hunor (FAO 370) and Norma (FAO 380) from the early maturity group and Maraton (FAO 450) and Sze SC 463 R (FAO 490) from the medium maturity group, grown at 20 different locations in Hungary. Each year the yield differences between the locations reflected the extreme distribution of precipitation during the growing season in different parts of the country. High amounts of precipitation were required in the growing season to reach the highest yields, but moderately high yields were achieved over a wide range of rainfall levels.

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The yield of maize is primarily influenced by sunlight, temperature, available plant nutrients and water supply. Since plants take up water through their roots, the most decisive factor is not precipitation but the quantity of water available in the soil. In this study, a simple, easy-to-reproduce, capacitive model was elaborated to determine the available moisture content for maize. During the calculations, based on the balance method, the available moisture content in the top 110 cm soil layer was determined, taking daily weather data into account. The examinations were carried out on a medium heavy chernozem soil with lime deposits, in a multifactorial experiment at the Látókép Experimental Station of the Center of Agricultural Sciences, Debrecen University, between 1990 and 2004. Annual yield fluctuation is primarily determined by the soil moisture content in the month of July and the water supplies in May, according to regression analysis. The maize yields in the past 15 years could be calculated with an accuracy of 570 kg/ha, an error limit of below 10% and an r value of 0.805, using a regression line and the data of monthly moisture supplies. However, the yields of fertilized plots can only be estimated with an accuracy of 1 t/ha on average. Fertilizer utilization is influenced by the moisture content of the soil, so it makes sense to include this in the analysis instead of the other environmental factors. Water is required for nutrient utilization. In years with poor or medium water supplies, moderate fertilizer rates are more effective, compared to higher rates in years with better water supplies. Efficient fertilization in maize production can only be achieved by harmonizing soil moisture content and the applied fertilizer rate.

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investigations were made on the relationship between plant density and plant height, and on the yield, thousand seed mass, and ratio of diseased and broken seeds of varieties with different seed sizes. Experiments were carried out to analyse the effects of potassium on the yield, bacterial diseases and nutritive quality of the seed of bean varieties. Three dry bean cultivars representing the small, medium and large seed size groups were investigated. Six plant density treatments were chosen based on theoretical seed norms, taking the germinative value of the seeds into consideration. The correlation between plant density and yield average showed that the volume of yield increased for varieties with large and medium-sized seeds up to a plant density of 285-400 thousand/ha, after which it declined. On the basis of the results, yield averages at plant densities of 285-334 thousand plants/ha were 0.17 t/ha higher than those achieved at low density (200 thousand plants/ha). At greater plant density the plant height increased in the case of large-seeded varieties and there was a considerable decrease in the thousand seed mass. With an adequate water supply a high level of potassium decreased the number of pods and seeds per plant compared with the basic level, which gave a yield of 2.5 t/ha. The use of high rates of potassium fertilizer decreased the number of infected seeds, but the differences were only significant for the small-seeded variety. A moderately high potassium level was advantageous for food quality, particularly during drought.

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The use of genetic markers allows the study of polymorphism and genetic distances between maize lines in greater depth than can be achieved on the basis of phenotype and DUS traits. The analysis of polymorphism between 46 maize inbred lines with known genetic background and the classification of these lines in related groups was carried out by means of morphological description, isoenzyme analysis, RAPD analysis, and identification using gene-linked microsatellite (SSR) markers. The genetic distance or degree of relationship between the lines was determined using cluster analysis. Only a very limited extent of allele polymorphism could be detected in isoenzyme analyses; the 46 lines formed only 18 gel electrophoresis groups. Nevertheless, on the basis of RAPD and SSR markers, all the lines could be distinguished from each other. This was reflected by the PIC (polymorphism index content) values, which ranged from 0.04 to 0.55 (mean 0.27) for the various enzyme loci, while far higher values were obtained for RAPD and SSR markers (0.20–0.91, mean 0.61, and 0.54–0.90, mean 0.73, respectively). Due to the large number of lines, two lines, derived from each other or from common parents, were chosen from each related group as the basis for grouping the lines according to genetic background. It was found that, while the individual marker systems only partially reflected the actual relationships between the lines, a joint processing of the genetic markers, supplemented with morphological data, revealed a close correlation between the groups formed on the dendrogram and the genetic background.

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The analysis of polymorphism between 46 maize inbred lines with known genetic background and the classification of these lines in related groups was carried out by means of morphological, isoenzyme and genetic markers. The degree of relationship between the lines was determined using cluster analysis. Only a very limited extent of allele polymorphism could be detected in isoenzyme analyses. Nevertheless, on the basis of RAPD and SSR markers, all the lines could be distinguished from each other. Grouping lines into related groups it was found that, while the individual marker systems only partially reflected the actual relationships, a joint analysis of genetic markers and morphological data revealed a close correlation between the groups formed on the dendrogram and genetic backgrounds.

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Recently, comprehensive molecular phylogenetic analyses of ribosomal DNA sequences have led to important advances in understanding the evolution of powdery mildew fungi (Erysiphales). These results have triggered major changes in the identification, taxonomy, and, thus, nomenclature of this group of plant pathogens. This paper reviews the recent nomenclatural changes of the Erysiphales and provides an up-to-date list of all the powdery mildew fungi reported from Hungary using the new names of the fungal taxa.

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The guidelines elaborated by the Community Plant Variety Office (CPVO) of the European Union for the registration and patenting of varieties and hybrids of cultivated crops are based on the triple criteria of distinctiveness, uniformity and stability (DUS). For many species, however, morphological descriptions are not sufficient for the detection of differences between varieties. Techniques that allow varieties to be identified and distinguished precisely and reliably are essential not only for variety identification, but also to protect variety ownership rights. Biochemical and molecular genetic methods have now reached a level of development that makes them suitable for this purpose, and when these are combined with conventional field observations the breeding stock can be unequivocally identified and any existing genetic diversity can be detected. The regular application of such analyses is a fundamental criterion in the case of maize, as more and more closely related hybrids are being entered for testing.The aim of the present work was to examine how isoenzyme patterns and PCR-based genetic markers could be used in polymorphism analysis, in order to obtain information on the genetic diversity of Hungarian breeding materials. The emphasis was on finding genetic markers characteristic of individual maize varieties, rather than of maize as a species.

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The chemical composition of maize makes it suitable for a wide range of nonconventional uses, including utilisation as a new source of energy for the 21st century as a raw material for biofuel. The aim of the experiments was to amalgamate the application of genetic markers with conventional breeding methods to produce maize hybrids whose starch content and ecostability satisfied the demands of industrial use, while having yield potential and agronomic traits on a par with those of hybrids currently cultivated. The chemical quality of 220 lines was evaluated using the NIR spectrometric technique, and the five maize inbred lines with the lowest and highest starch contents were selected for genetic marker studies. The variety identification of the lines was carried out using the isoenzymes stipulated by UPOV. The following SSR (simple sequences repeat) markers were tested: phi 095, umc 1057, nc 004, phi 096, nc 007, umc 1564, phi 85, y1 SSR, umc 1178, nc 009, phi 070, umc 1066, umc 1741, umc 1069, phi 033, phi 061, wx, phi 032, phi 084 and phi 062. The analysis of the fragment patterns revealed three SSR markers that appeared to be correlated with the starch content of the maize lines. These were the primer pairs y1 SSR, umc 1069 and phi 062 . These results are only of a preliminary nature, however, as the incorporation of starch is probably regulated by several genes, and the studies suggest it is also influenced by several environmental factors. It also appears likely that the bioethanol yield is determined not only by the starch content, but also by other parameters. Further research should thus be expanded to include investigations into the structural and fermentability traits of starch molecules, including the characterisation of these traits using genetic markers.

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The objectives of this study were to examine the correlation between factors of great significance for crop production, especially between irrigation and fertilization, and to evaluate the effects of irrigation and fertilization on maize yields over four growing seasons (2001-2004) in a long-term field experiment set up at the Látókép Experimental Station of the Centre for Agricultural Sciences of Debrecen University. The results showed that irrigation and fertilization were strongly correlated with the yield. The effect of irrigation depended on the natural water and nutrient supplies of the soil, and on the specific fertilizer rates. The results indicated that both fertilization and irrigation had a significant effect on the yield. The correlation between the year and the crop production factors was also significant. The yield-increasing effect of irrigation and fertilization differed significantly in the experimental years.

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The cultivation technologies for the dominant crops in Hungary need to be improved both in the interests of environmental protection and to reduce cultivation costs. A long-term research project was initiated in order to determine the feasibility of conservation tillage systems. The aim of the experiments was to evaluate conservation farming systems in Hungary in order to achieve more economical and more environment-friendly agricultural land use. Four tillage systems, namely conventional tillage (mouldboard plough), conservation tillage I (primary tillage with a J.D. Disk Ripper), conservation tillage II (primary tillage with a J.D. Mulch Finisher) and no tillage (direct drilling), were compared on a clay loam meadow soil (Vertisol). The physical condition of the experimental soils was evaluated using a hand-operated static cone penetrometer. Parallel with the measurement of penetration resistance, the moisture content of the soil was also determined. The grain yield of maize hybrids (Kincs SC [1999], Occitán SC [2000], Pr 37M34 SC [2001], DeKalb 471 SC [2002]) was measured using a plot combine-harvester. The analysis of soil conditions confirmed that if the cultivation depth and intensity are reduced the compaction of soil layers close to the surface can be expected. The decrease in yields (8-33%) in direct drilling (NT) and shallow, spring cultivated (MF) treatments, despite the higher available water content, can be explained partly by the compacted status of the 15-25 cm soil layer.

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