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Tan spot, caused by Pyrenophora tritici-repentis (Died.) Drechs., anamorph Drechslera tritici-repentis is one of the most important wheat diseases in the world, especially in the regions of intensive wheat growing. Tan spot had established for the first time in Latvia in 1994. Epidemic of this disease was observed in Latvia in 1998. Development of tan spot were investigated in field experiments at the Research and Training Farm "Peterlauki" of Latvia University of Agriculture in 1998-2001. Level of incidence and severity of tan spot differed depending on varieties and years. Severity of the disease was 16-71% in 1999; 0.1-5% in 2000 and 4-18% in 2001 depending on varieties at the time of ripening. 1999 summer was extremely dry, and development of disease was not observed. Explosion of disease was observed at the second half of June in 2000 and 2001, without reference to varieties. Date of increasing start differed, but in all cases important development was observed after flowering. Rate of increasing of disease was very high, during two weeks severity of disease increased from 0.1 till maximum of severity. Amount and frequency of rainy differed in 2000 and 2001, but increase on disease was very similar, it means, we need more information about favourable conditions for Drechslera tritici-repentis. Sexual stage Pyrenophora tritici-repentis was observed in Latvia for the first time. Further investigations are necessary, because relationships between meteorological conditions and stages of development are unclear.

The virulence frequency to 12 resistance genes present in the studied cultivars in the time before their first using in grown cultivars were estimated mainly based on the data of cultivar resistance in the field. The estimated virulence frequency is compared with results obtained from investigations of the air pathogen population in 2001. The comparison shows that virulence complexity increased from about 0.90 in 1971 to 8.73 in 2001. The increase in virulence complexity was caused by necessity of the pathogen to survive on cultivars possessing respective resistance genes, it means by direct selection [(Va1, Va6, Va7, Va9, Va13, Vat, Vk1, VLa, Vg and V(Kr)], indirect selection (Va12) and immigration (Va3).

Many factors, most notably climate, soil, genotype and fertilising, can influence barley grain composition and its nutritive value. The aim of the research was to evaluate the impact of mineral N rate in different management systems in the static long-term experiment with three years field rotation of grain maize, wheat and barley on the chemical composition of winter barley and its nutritive value for ruminants. Crude protein content and metabolizable crude protein content were increasing with increased mineral N rates. Higher yield meant lower crude protein and metabolizable crude protein content in all mineral N rates. The average crude protein content of barley grain, presented in DLG tables (1997), which is 12.4%, was in MM and SM reached by fertilising rate 110 kg N/ha. A significant impact of mineral N fertilising on crude ash, ether extract and crude fibre content could not be confirmed, nitrogen-free extract content was decreasing with increased mineral N rates. A significant impact of the management system on the Weende analysis parameters, net energy for lactation, metabolizable energy and metabolizable crude protein could not be confirmed. At both analyses a significant impact of the season was confirmed on crude protein content and nitrogen-free extract content. Although the protein content was increasing with increased mineral N rate from 9.2-14.2% (for 35%) ME content and NEL content did not significantly differ considering mineral N rate; ME/ha and NEL/ha increasing with increased mineral N rates was the result of the yield increasing with increased mineral N rates.

In the framework of PVS eradication from breeding materials of Czech potato cultivars, the systematic research was devoted to: susceptibility of cultivars, occurrence of PVS in imported and domestic materials, and to maintenance of virus-free basic grades potatoes on breeding stations. In the field-exposure trials was proved high level of susceptibility of most cultivars to PVS and by contraries, gradualy increased proportion of maintained virus-free cultivars of foreign, as well as domestic origin. Nevertheless severe infestation still persist in some of them. The contemporary situation with maintenance of virus-free basic material in CR was demonstrated.

Five cultivars of spelt wheat (Rouquin, Bauländer Spelz, Schwabenkorn, Franckenkorn and Holstenkorn) have been evaluated for baking quality by means of direct and indirect indicators. Three-year values of the indirect indicators have been statistically processed by the analysis of variance. Based on the results obtained we can say that all evaluated indicators except the extensibility of gluten were significantly influenced mainly by the year of growing. The cultivar itself was a less important source of variance, although some values of important indicators differed significantly according to cultivars. Based on indirect indicators such as the content of wet gluten, its extensibility and swelling, the content of N-substances, the sedimentation test in the modification with SDS, the falling number and the content of starch, the cultivars Schwabenkorn and Rouquin are considered as the most suitable and of the highest quality. In general all the cultivars of Triticum spelta L. showed high contents of N-substances (x = 15.46%) and wet gluten contents (x = 37.12%). Their disadvantages are lower swelling values (x = 9.3 ml) and lower sedimentation values (x = 37.4 ml) which have a negative influence on the bread volume and the specific volume (under 310 ml.100 g^-1). The predicted good baking quality of Schwabenkorn has been comfirmed in a baking experiment (direct method of evaluating the baking quality). There were good baking quality results for Bauländer Spelz as well. Unexpectedly bad results have been found with Rouquin, which showed the lowest water absorbing capacity of flour, the lowest bread volume, specific volume and baking extraction. The bread was just acceptable as far as taste is concerned. The baking from Holstenkorn was evaluated as excellent.

The processes of globalisation and concentration have been also penetrating into the Czech agro-food sector and market. Utilising information from foreign sources and developed countries, the paper tries to present a complex view on the Czech situation from the structural and institutional aspects. Based on limited Czech information sources, the market structure in the individual links of the food chains is presented, together with the hypothesis about the sequence of the market power in the present Czech agro-food sector: input suppliers and retailers - farmers - processors. The paper also implies possibilities of the state to suppress negative effects of globalisation and concentration, especially as regards the adjustment of the Czech market regulations to the EU ones.

Formation of strategic development intentions of Czech agriculture is determined from a viewpoint of external factors by European integrating processes and strengthening tendencies of globalisation. This multi-dimensional process is a driving power and at the same time also an eliminating factor of many development trends. The sustainable dimension of globalisation is formed in the frame of the world society, world economics, world ecology and world policy. Problems of world agriculture are represented by the intersection of these trends and present a starting point for the formation of the European and Czech agricultural policy.

Since 1990s, the discussion about the Czech social policy emphasizes more the necessity to change this policy from passive state social policy towards an active social policy. The latter includes the activities of people in the frames of formal (e.g. NGOs) and informal groups, and therefore also the concept of civic society is accentuated in this respect. Although this concept might be understood in different ways, its common characterization is a spontaneous non-political self-expression of individuals and their groups (the activity that was suppressed before 1989). Through the self-expression, the individuals realize their particular interests. When thinking about active social policy in the frames of civic society, we might assume that the conditions for its implementation are better for the actors in small rural communities. These more favourable conditions are assumed due to the traits of rural communities - e.g. personal, non-anonymous relations, good knowledge and familiarity with particular social problems, etc. However, the actors who try to contribute to active social policy are constrained/controlled in their activities by other community members. The level of these constrains depends on the configuration of social and cultural capital (Bourdieu). The author of the text is for more than one year involved in empirical research in one Czech village. Using qualitative methods she investigates various social events and actors who participate in active social policy (in relation to those who are supposed to participate in this policy as responsible agents). The author assumes that the participation in active social policy is one of the sources of integrated endogenous rural development, while passive social policy (institutionally backed by the state) is more related to exogenous rural development. However, there is a question how the very actors (active members of rural community) do approach this participation and how the other members of rural community evaluate their activities in the sphere of social policy.

The major insect pests on rice in Tanzania are listed and described. They are from five orders (Coleoptera, Diptera, Hemiptera, Lepidoptera and Orthoptera) and are discussed as stem borers, stem and root feeders, and leaf and panicle feeders. This review puts together the hitherto fragmented information available on the distribution, host range, biology/life-cycle and ecology, and the management measures of the insect pests of rice. Areas for future research are also mentioned.

Limited information on the resistance mechanisms in Lycopersicon spp. to Oidium neolycopersici is still available. Macroscopically the resistance is characterized by a very low amount of mycelium development and a lack of sporulation. The leaf surface did not effectively inhibite conidium germination, however significant differences in germ tube and appressorium development were recorded. A large variation was observed in host tissue response. The prevailing resistance mechanism was hypersensitivity (HR). Considerable changes of peroxidase and catalase activities during pathogenesis were detected among tested wild Lycopersicon spp. There was positive correlation between increasing of peroxidase activity and extent of necrosis. Histochemistry showed large differences in production of superoxid ions, H₂O₂ and peroxidase in Lycopersicon spp. with various level of resistance.

Relationship between initial oospore number of Pythium oligandrum, mode of the mycoparasite application and populationdynamics of Fusarium oxysporum f.sp. dianthi and development of Fusarium wilt of carnation was studied. Mixing ofoospores with peat 10 days before carnation planting resulted in strong inhibition of the pathogen development. Numberof colony forming units of the pathogen decreased at least 3 times. Application of P. oligandrum resulted in suppressionof Fusarium wilt development, especially when the mycoparasite was applied at dose 100 oospore/g of peat.

For 17 cultivars of winter wheat (Triticum aestivum L.) different vernalization and photoperiod responses were detected. The effect of photoperiod sensitivity was not significantly changed by vernalization; different vernalization responses were probably due to the presence of multiple alleles at Vrn loci. The delay in heading depended on the vernalization deficit exponentially: y = Parameter (1) + (y0 - Parameter (1)) × EXP (Parameter (2) × (x - x0)). The dependence was shown to be general and significant for the given model in all the studied cultivars. Individual regressions characterised responses of cultivars to a deficit of vernalization treatment. Cluster analysis according to the characterisation obtained (full vernalization requirement, minimum vernalization requirement, insufficient vernalization and parameters of the dependence) showed the relationships between cultivars and enabled their grouping by similar profiles of vernalization, and, possibly, of photoperiod response. In individual cultivars, an attempt was made to use the model to predict performance for some agronomic traits.

Ditylenchus dipsaci is one of the most harmful parasitic nematodes in Central Europe. It is able to survive for long time in soil without its host plants and that is why it belongs to organisms with quarantine importance. Nothing is known about D. dipsaci distribution in the Czech Republic. The aim of the study was to collect samples of D. dipsaci from the Czech Republic and to identify them by molecular methods. Region of rDNA including 3'end of 18 S gene, ITS1, 5,8 S gene, ITS2 and 5'end of 26 S gene was amplified using general primers designed according to the DNA sequence of Caenorhabditis elegans. The amplicon (900 bp) was analyzed by RFLP and SSCP. Restriction endonucleases Eco R1, Hinc II and Alu 1 can be used for differentiation of certain bioraces of D. dipsaci. At the same time methods for DNA extraction from plant material and contaminated soil were optimized.

In order to investigate cross-protection mechanisms between stresses of different origins, greenhouse experiments were conducted to determine whether resistance levels to the fungal pathogen P. capsici were affected on wounded plants. To this purpose, tomato roots were wounded at 24h-intervals and allowed to age for up to 7 days before inoculation. Data from preliminary experiments indicate first (0-48 h old wounds) an increase in disease severity in wounded as compared to unwounded tomato plants infected with P. capsici. Then, as the wounds age, disease severity decreases to the point that plants wounded 3 days before inoculation are less susceptible than nonwounded plants. Here, with the use of tomato mutant lines, we suggest the involvement of ethylene (C₂H₄) and jasmonates (Ja) in the development of these responses towards P. capsici upon wounding of tomato plants.

Rhizosphere and rhizoplane of fababean (Vicia faba), melochia (Corchorus olitorius), sesame (Sesamum indicum) and soyabean (Glycine max) plants are inhabited with fungi, mostly Aspergillus flavus, A. niger, Fusarium oxysporum, Penicillium corylophilum, P. cyclopium, P. funiculosum and Rhizopus stolonifer. All fungal species have the ability to produce gibberellin (GA) but F. oxysporum was found to produce both GA and indole-acetic acid (IAA). The optimum period for GA and IAA production by F. oxysporum was 10 days in the mycelium and 15 days in the filtrate at 28°C. The contents of GA and IAA were significantly increased at 0.5 and 1% NaCl after 5 days, but they were lowered at 4% (700 mM) NaCl. Cytochrome P-450 was significantly increased under salt stress at 0.5-7% NaCl. Calcium decreased NaCl stress on F. oxysporum by significant elevating GA biosynthesis at 40 mM Ca²⁺/700 mM Na⁺. GA at 10 µM and Ca²⁺ at 10 mM enhanced the germination of seeds under 175 mM Na⁺.

An experiment with five different tillage systems and their influence on physical properties of a silty loam soil (Albic Luvisol) was carried in northwest Slavonia in the period of 1997-2000. The compared tillage systems were: 1. conventional tillage (CT), 2. reduced tillage (RT), 3. conservation tillage I (CP), 4. conservation tillage II (CM), 5. no-tillage system (NT). The crop rotation was soybean (Glycine max L.) - winter wheat (Triticum aestivum L.) - soybean - winter wheat. Differences between tillage systems in bulk density, total porosity, and water holding capacity and air capacity were not significant in winter wheat seasons. In soybean seasons, significant differences between some tillage systems were recorded in bulk density, total porosity, air capacity and soil moisture. The deterioration trend of physical properties was generally increasing in the order CM, CT, CP, NT and RT. The highest yield of soybean in the first experimental year was achieved under CT system and the lowest under CP system. In all other experimental years, the highest yield of winter wheat and soybean was achieved under CM system, while the lowest under RT system.

In the paper, there is described using of the optimization models AGRO-3 SR for modeling food production chains in the Slovak Republic (the modified version of the Czech model AGRO-3) and ALOKA for optimal allocation of the domestic agricultural production computed by AGRO-3 SR into 4 different regions of the SR for simulation of consequences of various types of agrarian policies on the effectiveness of the Slovak agriculture to the medium-term horizon 2005. There are formulated and evaluated 4 scenarios for the model AGRO-3 SR and two alternatives A and B for the model ALOKA relating to all scenarios. Results of simulations have shown that the best result was reached in the scenario 4 by the price liberalization in the whole food chains.

In the framework of Slovakia preparation for entering the European Union, there was done a Phare-ACE survey in years 1999-2000. The name of this survey was "Micro-economic analysis of farming households restructuring in pre-accession period to the EU". This survey was done in two regions of Slovakia, characterized by different natural conditions, production and economic conditions. This project was aiming not only at private farmers but also at other legal entities producing agricultural products. The first monitored group consisted of 412 private farmers, farming in average 43.2 ha of agricultural land. The second group consisted of 150 businesses, having 1,866 ha of agricultural land in average.

On the basis of structure and qualitative parameters of agricultural soils, there are only 23.4% non profitable soils for the winter wheat growing in the total area of the Gemer Region. The same percentage for the corn maize growing is 78.7%, for the sugar beet growing 80.0% and for winter rape growing 46.0% of the total agricultural soils area in the mentioned region. Generally, for the crop production, it can be stated, that without production subsidies, at the present economic situation there are 65.9% soils non-profitable, 23.0% low profitable, 6.3% medium profitable and 4.8% high profitable in the Gemer Region. The calculated economic parameters can be used for a more effective production allocation and soil utilisation in different regions.

Authors summarise historical aspects of the renewable energy resources usage in the Czech countries, mainly of bio-mass. They are interested in the economic evaluation of the investment efficiency of usage or transformation of bio-mass. They supply facts of the approaching fossil fuels reserves exhausting and therefore an interest of growing trees and plants for energy usage. They indicate the possible utilisation of fallow land and of reclaimed land after the surface lignite mining for the purpose.

Occurrence of plum pox disease after natural infection was continually monitored between 1993 and 2000 in an experimental planting of plum trees where cultivars and hybrid seedlings were evaluated. All trees after finding symptoms of this disease were immediately grubbed. Summarization of the results has proved that infection of a tree significantly increased the risk of infection of neighbouring trees despite the fact that all infected trees were discarded. In the case of adjoining trees nearby, those within the same row increased their hazard by approximately three times and those between rows doubled their hazard in comparison with the average rate of infection of plum trees by PPV. This fact also highlights the significance of timely grubbing of affected trees immediately after an appearance of symptoms of this viral disease.

The objectives of this study are to determine the relationship between crown characteristics and the radial increment of beech (Fagus sylvatica L.) and to specify the characteristics of beech trees with the radial increment above the average in the Świętokrzyski National Park. The following relationships have been found: the radial increment of beech increases as the degree of the freedom of the light part of the crown from neighbouring trees increases, and the increase in the relative crown length causes a significant increase in the radial increment. Most of the best growing beech trees are characterized by the light part of the crown confined in an area of up to about 55%, and the relative crown length spanning the range of 55% (trees 61 to 80 years of age at b.h.) to 76% (trees 21 to 40 years of age at b.h).

The resistance of six cultivars of winter oilseed rape (SL 509, SL 507, Darmor, Solida, Jet Neuf, Silesia) against Turnip yellow mosaic virus was studied. The number of over-wintering plants and plants with symptoms of TYMV infection were monitored. All plants were tested by the double diffusion test in agar and by DAS-ELISA to prove infection. ELISA was the most sensitive method, revealing 32-76% of latent virus infections in individual cultivars. The results clearly illustrated that monitoring of plant symptoms is not sufficient to prove TYMV infection in the field and that sensitive, large scale methods like ELISA must be employed to obtain reliable data.

To search for host proteins involved in systemic spreading of Tomato spotted wilt virus (TSWV), the virus-encoded NSm movement protein has been utilized as a bait in yeast two-hybrid interaction trap assays. J-domain chaperones from different host species and a protein denominated At-4/1 from Arabidopsis thaliana showing homologies to myosins and kinesins were identified as NSm-interacting partners. In this communication we illustrate that following TSWV infection, J-domain proteins accumulated in systemically infected leaves of A. thaliana, whereas At-4/1 was constitutively detected in leaves of A. thaliana and Nicotiana rustica.

Field resistance can contribute to reductions in epidemic progress of Septoria tritici in winter wheat. Crop growth andcanopy architecture are identified as key mechanisms of field resistance. Near isogenic lines differing for dwarfing (Rht)and photoperiod sensitivity (Ppd) genes, enabled the study of target traits in a constant background of genetic resistance.Epidemics were consistently earlier in shorter crops across a range of environments. The mechanism for this effect wasidentified as an increase in spore arrival due to a reduction in the required dispersal distance between infective tissueand emerging upper culm leaves.

A survey of development and prospects of the utilisation of doubled haploid techniques in rapeseed breeding in the world and in the Czech Republic is presented. The first utilisation of spontaneously occurred haploids from Brassica napus inbreeding programmes is described. The development of techniques of anther and later microspore culture is outlined. Special emphasis is given to the practical use of doubled haploids for the improvement of the effectiveness of breeding new productive cultivars. Some partial results of evaluation of yield parameters and resistance to important diseases in the obtained doubled haploid lines of winter oilseed rape are shown. The literary review and present results indicate, that the doubled haploid technique can be effectively used for the development of homozygous oilseed rape lines as an alternative to conventional methods.

Isolates of Fusarium oxysporum f.sp. ciceri from chickpea (Cicer arietnum L.) can be characterized as races and wilt and yellowing pathotypes by pathogenicity tests on varieties of differentials chickpea. This study shows that, DNA bands generated by RAPD-PCR can be used to assign Fusarium oxysporum f.sp. ciceri isolates to pathotype and pathogenic race.

Strawberry anthracnose, caused by Colletotrichum acutatum, is one of the most destructive disease of this crop throughout the world. Assymptomatic stages in the plant have been the aim of this work. Inoculated leaves samples were taken at different times and they were processed for scanner electron microscopy (SEM) and transmission electron microscopy (TEM). Conidial development on both surfaces leaves was determined. The ultrastructural study of fungus penetration into plant cell was characterized by the formation of vesicles over the fungus periphery and is a morphological parameter of the intense membranes traffic, also could be a evidence of a transcriptional activity and enzymatic cell secretion. Differences of symptoms on both surfaces of leaves were observed.