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An assortment of 15 cultivars of root parsley was studied in field experiments to evaluate morphological characteristics, market yield, content of selected minerals and nitrate content. Storage ability of roots was also assessed. Mean root weight ranged from 87 g (cv. Bartowich Long) to 129 g (cv. Atika). Root head diameter was from 39 mm (cv. Lange) to 49 mm (cv. Halflange Omega and Hamburg). Mean root yield amounted to 1.35 kg/m² and the highest value was found in cv. Atika. Nitrate content did not exceed the tolerance limit ranging from 113 to 617 mg/kg of f.m. Mean content of K was 4,690 mg, Ca 124 mg, Mg 509 mg, and Na 425 mg/kg of f.m. Weight losses ranged from 10 to 32%; cv. Jadran showed the lowest value. Newer Czech cultivars (Atika, Jadran, Orbis) had a good commercial and growth potential.

Caraway fruits contain 1-6% of essential oils consisting of about 30 compounds, from which carvone and limonene account form the main portion, about 95%. To evaluate the quality of various caraway cultivars, the amounts of essential oils and the carvone/limonene ratio were measured. The most common method of essential oil evaluation is steam distillation in accordance with Standard ČSN 58 0110, but an alternative method - supercritical fluid extraction (SFE) - was also investigated in this paper. Ground caraway fruits were extracted under different SFE conditions (pressure, temperature, use of modifiers). Released compounds (carvone and limonene) were quantified by GC.

These traits of fruit colour were evaluated in 24 apricot genotypes for six years: basic colour, overcolour, flesh colour and attractiveness. The evaluation involved variability of colour traits and correlations between these traits in a six-year period. The evaluated genotypes were significantly different in colour traits; it will facilitate the selection of commercially interesting genotypes. Highly significant correlation coefficients (r = 0.56⁺⁺ to r = 0.96⁺⁺) were calculated for the rank of the values of particular traits in 1994-1999; it confirmed that the traits are genetically conditioned. As for the correlations between the traits, the closest correlation was found out between basic colour of fruit and flesh colour (r = 0.53⁺⁺ to r = 0.96⁺⁺) and between basic colour and overcolour (r = 0.45⁺⁺ to r = 0.65⁺⁺). In the six-year period fruit attractiveness showed the lowest variability expressed by average coefficient of variation (v = 14.98%) while fruit overcolour had the highest variability (v = 41.14%). The coefficients of variation for basic colour and flesh colour were at a medium level. Harogem and Harlayne were the most interesting varieties by their colour traits. Among the registered and most frequently grown varieties in the CR it was Velkopavlovická LE-6/2. The varieties Lednická M-90-A and Vynoslivyj were the most promising for producers by their colour.

The paper widely introduces European experience in wild cherry breeding because it is the first one from a prepared series of articles aimed at wild cherry breeding in the Czech Republic. Beginnings of wild cherry breeding program for the Czech forestry are described. Plus trees were certified, seed orchards, clone archives, progeny and clonal tests were established. Clones were tested for fl owering of grafts in reproductive plantations. Progenies and clones were tested for growth parameters in progeny and clonal tests. Progenies and clones in every breeding plantation were tested for damage by aphids.

A new method for evaluating damage caused by tenthredinids to Norway spruce stands is based on defoliation of the top whorls. A scale with four classes of defoliation was established that is easy to use. Defoliation can be displayed graphically on a grid map (Central European system), in which the map fi elds are delimited by parallels of latitude (6 by 6 minutes) and meridians (10 by 10 minutes) with an approximate size of 11.2 × 12.0 km. The degree of defoliation for an entire forest can be marked by circles of different size in the map field. The range and intensity of an infestation, and the change in defoliation from year to year are easily seen.

Sissoo (Dalbergia sissoo, Roxb.) is a nitrogen fixing leguminous tree species with natural habitat in the lowland region of Nepal called Terai up to an altitude of 1,000 m. For the last few years, this economically important tree species has been dying rapidly in the plantation forests. On the contrary, its status in the natural forest in riverine areas has been unknown yet. The paper compares the nutrient status of natural and healthy sissoo forest with declining plantation sissoo one. It is evident from this study that both stands do not differ very much with respect to their soil and plant nutrients. Therefore it was concluded that the waterlogging of soil was the main factor responsible for the decline of plantation sissoo forest.

The basic principle of the economic reform of state forests of the CzechRepublic after 1990 was to separate ma­nagement in forests from the implementation of production activities. A state enterprise Forests of the Czech Republic with its headquarters in Hradec Králové was charged to manage state forests. From the former 7 enterprises of state forests 78 joint-stock companies have been established that carry out silvicultural and logging activities in state forests and in forests of other owners under the conditions of competition environment and on the basis of contracts. The paper deals with the exact evaluation of partial and present results of the development of forestry economic reform, aimed at the study of the behaviour of transformed and privatised forest joint-stock companies.

The present study documents the effects of green alder [Alnus alnobetula (Ehrh.) C. Koch] on the uppermost forest soil layers in mountain areas, respectively in the summit part of the Jizerské hory Mts. Pedochemical characteristics of holorganic horizons in stands of this species, established in 1992 on a clear-cut caused by air pollution, were compared to the status of soils in stands of bog pine (Pinus rotundata Link.). Extreme site conditions and young age of both stand types resulted in low effects on the humus forms in the first decade. Despite of this, enrichment in total nitrogen content and tendency to acidification due to nitrate leaching were obvious and statistically significant in green alder stands.

The subject of this paper was to assess the effects of pulverised dolomitic limestone applications on prosperity of Norway spruce (Picea abies L.) plantation and on the soil in extreme ecological conditions of the Jizerské hory Mts. The characteristics such as plant mortality, annual height increment, diameter of root collar (stem base diameter), crown diameter, nutrient analyses and some data from soil analyses are evaluated in this paper. An eleven-year period of observations is summarised. According to the observations and measurements carried out until now, the effect of limestone applications (1 kg per tree) on the spruce plantation prosperity seems to be positive without any serious negative impacts on the soil.

Sweet chestnut Castanea sativa Mill. is an introduced species in the Czech Republic. It is recorded roughly from 300 localities. To the end of 2002, the occurrence of chestnut was verified at about 140 macrolocalities. The most northern locality recorded so far was Choustníkovo Hradiště in the region of Hradec Králové. Chestnuts occur generally to an altitude of 500 m (80% of all examined localities), at higher altitudes they suffer from climatic extremes particularly late frosts. The occurrence of chestnut was recorded at 27 localities (ca. 20% localities under investigation) where altitudes exceed 500 m. The highest location of chestnut is locality Nejdek, Karlovy Vary District where chestnut trees thrive at an altitude of 678 m. At altitudes over 600 m, two other localities were recorded. The health condition of chestnut is relatively good. At some localities, however, crown drying occurs as a result of not quite ideal climatic conditions. Within our research, quarantine Cryphonectria parasitica (Murr.) Barr. was determined for the first time in the Czech Republic at the only examined locality.

Summarization of the potential of introskeletal erosion (ISE) was done on the basis of field surveys in the Šumava Mts., Krkonoše Mts. and Jeseníky Mts. areas. The results give a rough estimation of the ISE extent in mountain forests of the Czech Republic. They indicate that in the mountainous areas of the Czech Republic there are 46,535 ha of forest lands endangered by these processes, which represents 10.1% of mountain forests and 1.7% of the total forest area in the country. The worst situation is in the Krkonoše Mts., where the considerable ISE potential is on 30.5% of forest area (in the Jeseníky Mts. 16.6%, in the Novohradské hory Mts. 13.3%, in the Šumava Mts. 8.2%). Because these areas are relevant production and water protection areas, the ISE processes have to be studied carefully and forest lands have to be protected, also using special technologies for forest protection and restoration.

Models evaluating static stability (resistance to breaking or uprooting of trees caused by wind, snow or ice) of forest stands in the seventh altitudinal vegetation zone were determined. The empirical material came from 180 research plots (High Tatra and Low Tatra Mountains) established within the research project Research on methods for mountain forest management based on sustainable Development. Static stability was characterized by the slenderness ratio that was calculated from the mean height and diameter of target trees. Then the particular forest stands were categorized with regard to slenderness ratio, mean diameter and absolute site class using either tables or graphic models. Particularly, four static stability classes were made up: 1 - very good, 2 - good, 3 - sufficient, and 4 - insufficient. Practical application of the models is shown for forest stands grown in the area of Vajsková and Lomnistá valleys.

The paper presents the results of evaluating the growth and health of 20 different poplars from the Aigeiros group in 30-year populetum Leles on uninundated alluvia of the Latorica River in ecological conditions of the lowland Východoslovenská nížina. The populetum is situated on medium-heavy loamy soils in the group of forest site types Ulmeto-Fraxinetum carpineum. The results of evaluation document that out of the investigated poplar clones the poplars I-214, I-476, Blanc du Poitou, Flachslanden and P. nigra (Baka 5) had the best height and diameter growth and maximum volume production. Their health status was also very good. The lowest volume production was determined in P. nigra (009/66 ČR), I-455 and Grandis, and the worst health was found out in Grandis, P. nigra (Pavlovce 1) and P. nigra (Ivachnova 1). These results will facilitate to include the poplars I-476 and Flachslanden in the assortment of regionalized poplars for the lowland area of Východoslovenská nížina.

The incidence of Zucchini yellow mosaic virus (ZYMV) was monitored in the south Moravian region of the Czech Republic during 1997-2001. Crops of gherkin, squash, zucchini and cucumbers were found infected with ZYMV, manifested by symptoms of severe stunting and yellowing with deformed leaves and fruits. Twenty to eighty percent of infected plants were recorded. Six isolates of ZYMV from four localities were differentiated on indicator plants; three of them were maintained as being typical for differences in pathogenicity. Overwintered weed species were tested for the presence of the virus. ZYMV was detected by ELISA in one plant of Tripleurospermum maritimum out of 46 tested, and in two plants of Stellaria media out of 29 tested in 2001. Such tests were repeated in 2002, and ZYMV was detected in three plants of T. maritimum out of 45 tested, in three plants of S. media out of 52, and in two plants of Trifolium repens out of 17 tested. The virus was successfully transmitted from T. maritimum, S. media and T. repens to indicator plants of Cucurbita pepo convar. giromontiina. Back-transmission of ZYMV was proved by ELISA, electron microscopy and symptoms. T. maritimum was found to be a new natural host of ZYMV.

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.

Among natural resistance mechanisms to plant pathogens, cultivar resistance has been extensively used in plant breeding to introduce what can be defined as "conventional" resistance to a number of them, including viruses. The necessity of overcoming the constraints of genetic incompatibility, so as to widen the range of possibile use of genetic control of infectious agents, has propitiated the utilization of biotechnological procedures, whereby "non conventional" or transgenic resistance was developed. Transgenic resistance to plant viruses encompasses the identification, cloning and tranferring into the recipient host of single viral genes, which gives rise to what is known as "pathogen-derived resistance" (PDR). Of the hypothesized mechanisms underlying expression of PDR, post-transcriptional gene silencing has been most extensively investigated in recent years. Despite of the success that virus-resistant cropping of transgenic plants begins to enjoy, in Europe there is still a widespread sentiment against agricultural biotechnologies and the use of genetically modified plants in particular. Yet, experimental evidence is accumulating that, in the case of PDR, the feared risks associated with genetic trasformation are minimal, if not negligible

The effect of barley-legume intercrop in an organic farming system on disease incidence was investigated. The legumeswere lupin, faba bean and pea. Diseases were detected on pea and barley. On pea, only ascochyta blight (Ascochyta pisi)was observed. When either pea variety was intercropped with barley, the level of ascochyta blight was reduced. Netblotch (Pyrenophora teres), brown rust (Puccinia recondita) and powdery mildew (Blumeria graminis f.sp. hordei) (inorder of incidence) were monitored on barley between flag leaf emergence and heading. The levels of all three diseaseswere reduced in every intercrop treatment compared to the barley monocrop. However, this reduction was only statisticallysignificant in the pea treatments for net blotch.

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.

Two resistance phenotypes to P. brassicae have been found in A. thaliana. A first resistance phenotype has been detected to the isolate 'e₂' and is polygenically inherited. The second resistance to isolate 'e₃' is caused by the dominant resistance gene RPB1. By crossing no influence could be shown for salicylic acid, jasmonic acid and ethylene in the latter resistance reaction. The RPB1 locus was narrowed down to 71 kb on chromosome 1, where three pseudogenes and 13 coding sequences are located. Six of them showed cosegregation with RPB1. None of these sequences have similarities to identified resistance genes or other known genes. Ten coding sequences were expressed, but CDS9 was exclusively expressed in the resistant ecotype Tsu-0.

A scanning electron microscope study of citrus fruits was performed to assess the colonization process of antagonistic yeasts to green mould of Tarocco oranges under artificial inoculation. Yeast suspensions of Debaryomyces hansenii DBVPG 4025, Pichia guilliermondii NRRL Y 18134, P. anomala J121 and Saccharomyces cerevisiae P1.6 with or without addition of 1% CaCl₂ + 0.1% Tween 80 were evaluated. Penicillium digitatum was sprayed one hour later. Observation of fruit surface waxes revealed marked morphological diversity. Yeast cells and conidia were mostly localized on epicuticular waxes, particularly in naturally occurring small pits. The size of the wound affected the number of yeasts and conidia penetrating inside. Treatment with CaCl₂ did not affect the waxes and/or the behaviour of the yeasts and pathogen.

The effect of fluridone (or flurochloridone), the inhibitor of carotenoid, chlorophyll and abscisic acid synthesis, on the abscission of Ligustrum vulgare leaves was investigated. Both forms of fluridone inhibited the abscission of petioles when they were applied as a 1.0% concentration in lanolin to the leaf blade. Fluridone was capable of inhibiting abscission even when it was applied to the petiole as late as 7 hours after the blade was cut off. Fluridone applied in lanolin to the apical part of intact pea seedlings or on the cut surface after decapitation of the epicotyl caused albinism of the stipules. The degree of albinism decreased according to the concentration of applied flurodine (from the highest - 0.5% to the lowest - 0.03%) and was higher in intact than in decapitated plants. Albinism also appeared in pea seedlings grown from seeds swollen in differently concentrated solutions of flurochloridone, particularly in the basal part of the shoots. Complete albinism occurred only in plants cultivated from seeds swollen in high concentrations (0.06-0.12%). The lowest concentration (0.007%) stimulated root growth of the pea seedlings, but inhibited epicotyl growth.

A new method was proposed that complements the value of active carbon in the soil expressed as hot-water soluble carbon Chws. The method is based on vacuum measurements of biochemical oxygen demand (BOD) of soil suspensions using an Oxi Top Control system manufactured by the WTW Merck Company that is destined for hydrochemical analyses of organically contaminated waters. Measurements will provide BOD values for particular days of incubation; total limit BODt can be determined from these values, and it is possible to calculate the rate constant k1 of mineralization of a decomposable part of soil organic matter. It is typical of soil organic matter (SOM) of a given soil sample and comparable with the BOD5:COD (chemical oxygen demand) ratio that is used to evaluate degradability of water organic contamination in hydrochemical analytics.

Problems concerning total dry weight and distribution of underground phytomass were studied in a pasture trial at Rapotin near Šumperk, the CzechRepublicin the period 1995-1999. The total weight of dry underground pasture phytomass (DUP) was 976 g/m² (5-year average) in a soil layer of 0-200 mm (both live and dead roots). The DUP was significantly increased by mineral fertilizers (90 kg N/ha, 30 kg P/ha a 90 kg K/ha). The weight of DUP was not significantly influenced by a grazing system, renewal or resowing of the original grassland. In unfertilized plots, DUP weight amounted to 989 g/m², i.e. 92 g/m² (8.6%) less than in fertilized plots in the period 1996-1999. In the same period, under the grassland exploited by rotational grazing 1142 and under continuous grazing 1082 g/m² DUP were determined, i.e. by 60 g/m² (5.5%) less. The highest DUP weight in the period 1996-1999 was found in autumn 1997 (1222 g/m2) immediately before achieving the maximum forage yield in May 1998. In a layer of 0-20 mm, 54.6% of the total DUP was found. In this surface layer, significant increase in the DUP weight was found in fertilized plots. In 1999, some 88.5 and 90.2% of DUP were concentrated in unfertilized (903 g/m²) and fertilized (952 g/m²) plots, respectively in a layer of 0-100 mm.

A survey was made to evaluate sanitary status of grapevines in the Czech Republic with regard to occurrence of economically important viruses. Propagation material of 109 grapevine clones was tested for presence of Grapevine fanleaf virus, Arabis mosaic virus, Grapevine leafroll-associated virus 1, Grapevine leafroll-associated virus 3, Grapevine virus A, Grapevine virus B and Grapevine fleck virus. Dormant canes were collected and cortical scrappings were analyzed by DAS-ELISA. All seven viruses tested were found to be widely spread in Czech propagation material of grapevine. From 330 individual vines tested, 148 vines were found to be infected with at least one virus. From 109 clones tested, in 98 clones at least one vine negative for tested pathogens was found. Such vines were promoted as candidate plants into screenhouse in Faculty of Horticulture Lednice and will be further tested by other methods. Sanitation of infected grapevine clones is needed in near future.

The genetic diversity and the relationships among rapeseed germplasm, including a collection of 20 Chinese, 25 Czech, 2 German, 2 French, and 1 English cultivars and breeding materials were evaluated using random amplified polymorphic DNA (RAPD) markers. A total of 79 different polymorphic amplification products were obtained using10 selected decamer primers. RAPDs revealed a significant level of polymorphism among the accessions. The diversity index (DI) ranged from 1.390 to 3.491, showing a sufficient potential of selected primers to differentiate among studied genotypes. Three different metrics were used to assess genetic diversity. The best fit between a priori knowledge about germplasm origin and a posteriori grouping was found using Hamman metrics. Cluster analysis based on Hamman pairwise distance comparison divided the studied accessions into three main clusters. The first group included only accessions fromChina, the second group only that fromEurope with the exception of Zhongshuang No. 2, a Chinese winter rape possessing European cultivars in the pedigree. The third group included accessions both fromChina andEurope. The results indicate the occurrence of a considerable genetic variation between Chinese and European accessions.

Molecular sampling of HSVd in grapevines in the environs of hop gardens was performed. Specific RT PCR primers were designed to unambiguously distinguish between HLVd and HSVd infections. These primers were used for detection and analysis of HSVd cDNAs from individual samples by thermodynamic methods, TGGE and cDNA heteroduplex analysis. We found that at least 70% of grapevine samples from locations close to hop gardens inNorthern Bohemia(Žatec and Úštěk hop production areas) were infected with HSVd forming populations containing quasispecies. Particular sequence variants, dominant in grapevines from wine-growing areas like Znojmo, were also found in minor private vineyards. HSVd was experimentally transmissible (80% success) from these samples to Osvald's clone 72 of Czech hop, where according to the cDNA library screening, one of the dominant HSVdg variants corresponding to AC E01844 was detected in early populations three weeks p.i. HSVd was detected neither in reproduction materials nor in examined hop gardens. However a potential danger for hop cultivation, consisting in the high biological potential of HSVd spread is discussed.

As, Cd, Pb and Zn accumulation in the aboveground biomass of seven clones of Salix spp. and changes in element uptake by plants after element addition to soil were studied in a pot experiment. Unpolluted Chernozem (Suchdol) as a control and soils with addition of As (100 mg/kg), Cd (40 mg/kg) and either Pb (2000 mg/kg) (Suchdol-Pb) or Zn (2000 mg/kg) (Suchdol-Zn) were used for the experiment. Significant differences were found in the accumulation of elements between willow clones and also between different element additions to the soil. Although As and Cd uptake slightly increased in Suchdol-Zn soil compared to Suchdol-Pb soil, the element removal from soil was significantly higher in Suchdol-Pb soil due to a significant reduction of aboveground biomass yield in Suchdol-Zn soil caused by Zn phytotoxicity. The yield reduction decreased the uptake of plant-available elements by biomass, thus higher plant-available portions of As and Cd were found in Suchdol-Zn soil. Element removal from soil was more dependent on element contents in willow tissues in Suchdol-Pb soil than in Suchdol-Zn soil, where willow plants exhibited physiological symptoms of phytotoxicity.

Changes in N-NO3- content and N-NO3- increase after incubation were studied in 1992-1998 in soils of two farms situated in identical soil and climatic conditions (in spring and autumn seasons). The two farms produce sugar beet and grain crops, but since 1991 they have used different types of organic fertilizers. Farmyard manure has regularly been applied to root crops on Dobrá Voda farm; since Chvalina farm does not have animal production, green manure and plowing-in of beet tops and straw are used for organic fertilization. Soils with regular applications of farmyard manure show a trend of lower N-NO3- content than the soils of the farm without animal production. At Dobrá Voda N-NO3- content was about 12 ppm N in spring and 9 ppm N in the autumn season while the respective values for Chvalina were 14 and 10 ppm N. On the hand, N-NO3- increase after soil incubation (12-14 ppm N) was higher in Dobrá Voda soils than in soils from Chvalina farm (5-8 ppm N).

Zinc distribution in the main soil fractions and zinc accumulation in potatoes, maize, wheat and barley after different soil treatments (basic sludge rate, triple sludge rate, NPK, NPK + inorganic Zn) were investigated in a field experiment conducted at five localities of the Czech Republic (Červený Újezd, Hněvčeves, Humpolec, Lukavec, Suchdol) with different soil and climatic conditions. Three soil types were investigated in the experiment: clay-loamy Chernozems, loamy Luvisols, clay-loamy Luvisols and two loamy Cambisols. Sequential analyses provided an overview of soil Zn distribution in the following fractions: exchangeable, Fe-Mn oxide, organic and residual ones. The sludge and inorganic Zn addition supported Zn mobility growth and higher Zn retention in Fe-Mn oxides in all tested soils. The influence of the above-mentioned treatments on higher Zn association with soil organic compounds was not explicitly found. Potatoes, wheat and barley accumulated more Zn after its addition into the soils by sludge and inorganic salt. By contrast, Zn content in maize decreased with higher input of Zn into the soil. The highest Zn concentrations were usually observed in plants grown on both Cambisols.