Guidelines in European Union for N management in orchards aim to limit fertilizer applications under threshold limits, in order to reduce N losses to the environment, but at the same time to attain optimum tree growth, high yield and good fruit quality. The experiment was carried out at the Wilanów Research Farm, situated in the postglacial valley of the Vistula River, on a fertile silty loam alluvial soil. The soil of the field assigned for the experiment was at the depth of 0–20 cm, slightly acid (pH_KCl = 6.0), showed high available Mg (16.6 mg%) and P (6.6 mg%) contents, medium available K (19.6 mg%) and a low K/Mg ratio (1.2). Considering a low ratio of K to the other kations as well as occasionally appearing K deficiency symptoms in the neighbouring orchard, before tree planting potassium salts were applied at the rate of 200 kg K₂O ha^-1. Throughout all the years of studies potassium, magnesium and phosphorus fertilizers as well as liming soil were not applied. 'Jonagored' apple trees on M.9 rootstock were planted in spring 2000, spaced 3.5 × 1.5 m. From spring 2000, five fertiliser treatments were applied: (1) N-0 (check); (2) N-50 (50 kg N ha^-1), over the whole orchard area in early spring); (3) N-100 (100 kg N ha^-1, over the whole area, in early spring); (4) N-100_delayed (100 kg N ha^-1, in early spring, starting from the fourth year after planting 2004); (5) N-100_sward (100 kg N ha^-1, in early spring, starting from the fourth year after planting, in sward alleyways only). Nitrogen was applied as ammonium nitrate, before the start of vegetative growth. After 10 years, the higher dose, i.e. 100 kg N ha^-1 applied from the first year after planting resulted in the smallest trunk cross-sectional area (TCSA), during when the same dose starting from the fourth year after planting resulted in the highest TCSA. N fertilization did not significance effect on growth of the trees as compared with not fertilized control. The first yield was harvested in the 3^rd year after planting (2002), but in any year neither dose or mode of N fertilisation had any significant effect of yield. The cumulative yield for the years 2002–2009 and fruit size did not depend on N fertilization either. No significant response to nitrogen fertilization was noted on cropping efficiency coefficient for eight years of bearing in relation to the final trunk cross-sectional area.

Drechslera leaf spot in the common oat (Avena sativa L.) is caused by D. avenae (syn. Pyrenophora chaetomioides, Helminthosporium avenae). Susceptibility of various oat cultivars and breeding lines to leaf infection by this pathogen was investigated in the field in 2001–2002 and in a growth chamber. After natural infection in the field, brown or brown-red spots caused by D. avenae were found in all oat genotypes and both years, but were less common in the drier and colder growing season (2001). Mean values of leaf infection index in the studied oat genotypes for the 2 years varied from 5.65 (CHD 2100) to 10.33 (Akt). After artificial inoculation in the growth chamber, symptoms were similar but leaf infection index was much higher – from 15.0 (Bajka) to 41.3 (STH 4699). High-performance liquid chromatography showed that anthraquinone derivatives produced by strain 1 of D. avenae include anthraquinone compaunds – cynodontin and helminthosporin. These compounds are known to limit the growth of some other pathogens and saprophytes.

Oil pumpkin (Cucurbita pepo L. var. styriaca) seeds and Jerusalem artichoke (Helianthus tuberosus L.) tubers are alternative horticultural products containing important biologically active components. The objective of the three-year study was to determine dry matter and micro-, macroelements accumulation in seeds of oil pumpkin Cucurbita pepo L. var. styriaca – ‘Miranda’, ‘Golosemiannaja’, ‘Herakles’, ‘Danaja’, ‘Olga’; and in tubers of Jerusalem artichoke (Helianthus tuberosus L.) –‘ Rubik’, ‘Albik’, ‘Sauliai’ and selection lines Nr. 05-1, Nr. 05-7. Macro- and microelements were determined by mass spectrometer. The highest amount of Ca, K, Fe, Mn, Se and Al was accumulated in oil pumpkin seeds of cv. ‘Miranda’ and amount of Ca, Mg and Se was identified in cv. ‘Rubik’ and K, Na, in ‘Albik’ Jerusalem artichoke tubers.

Priming is one of the most common methods improving quality of seeds. The purpose of the research was to study effects of osmopriming combined with grapefruit extract (Biosept 33 SL) treatment on zinnia seed germination, vigour and infestation with fungi at 10 and 20°C. Two seed samples, cv. Kirke and Orys, varying in initial infestation with Alternaria zinniae, were treated with Biosept 33 SL solutions at concentrations of 0.05, 0.25, 0.5 and 1.0%, during and after priming in polyethylene glycol (PEG 8000). Controls were untreated seeds, seeds treated with fungicide Sarfun T 65 DS and seeds soaked in 0.05, 0.25, 0.5 and 1.0% Biosept 33 SL solution. Priming alone, as well as priming combined with grapefruit extracts treatment, significantly improved total germination and vigour of the seeds. Impact of Biosept 33 SL treatment on seed health varied among samples and was strongly influenced by initial seed infestation with fungi, applied doses of the preparation and temperature of incubation.

In the world of orchard science there is a trend of constant limiting the size of fruit trees of almost all species. That is why there is a continuous search for new rootstocks reducing the vigour of growth of the cultivated plants. The experiment was conducted at the Experimental Station of the University of Life Sciences in Poznań, in the years 2008–2009. The aim of this study was to estimate of 15 clones obtained by crossing A2 × B.9 rootstocks to check their usefulness for the production of maiden apple tress of ‘Galaxy’ and ‘Rubin’ in a nursery. M.9 and M.26 rootstocks were used as a standard. The strongest growth of maiden apple trees was obtained on M.26 rootstock and on the clone number 15. The growth of trees on clone number 5 was weaker than those on M.9 rootstock. Maiden apple trees of ‘Rubin’ cultivar did not create lateral shoots for most rootstocks. The biggest number and total number of lateral shoots was found on the trees of ‘Galaxy’ on rootstocks clones number 1, 3, 6, 7, 10, 13 and 15 and the least on clones number 2, 5 and 9. The biggest number of skeleton roots had trees on M.26 rootstock and the fewest on M.9 one. The biggest number of maiden trees in comparison with the budded rootstocks was obtained for clones number 6, 10 and 13 and the fewest for clones number 2, 7, 8, 9 and 11. For all clones the percentage of trees meeting the requirements of the standards was high and the results did not differ from those on M.9 and M.26 rootstocks.

Ajania pacifica has been gaining popularity as a pot plant. It is closely related to the chrysanthemum, and may become an interesting alternative for it, the more that the cultivation of both species can be carried out simultaneously. The aim of this study was to assess the growth and flowering of ajania as a result of pinching and the day length of pinched plants. The present research involved the use of Ajania pacifica, ‘Silver and Gold’ and ‘Bea’ ‘Benetti’ and ‘Bengo’ (of Bellania group). The first cultivation was made in the long-day glasshouse. Having been planted into pots, the plants of each cultivar were divided into groups: non-pinched and pinched once, and the last group: further divided into: allocated to immediate cultivation exposed to short day and those which, before the second stage of cultivation – plant darkening for the period of two weeks, were grown further under long-day conditions. Not all the cultivars reacted in the same way to pinching. In ‘Bengo’ the pinched plants formed buds and started flowering at a similar date as the non-pinched ones, in ‘Benetti’ and ‘Bea’ the delay was inconsiderable and in ‘Silver and Gold’ the buds appeared 5 to 12 days later. The plants growing longer under long-day conditions were higher, wider, with longer and wider corymbs, more inflorescences and their life was longer.

Thirty-three species were recorded from various ornamental field plants, representing 23.08% of the native Polish scale insects fauna. These species belong to 6 families, namely: Asterolecaniidae, Coccidae, Diaspididae, Eriococcidae, Kermesidae and Pseudococcidae. The best represented families were the Diaspididae (13 species) and Coccidae (12 species). For each species, the type of habitats, host plants, pest status and zoogeographical region of origin are given. Scale insects were found on cultivated deciduous trees and shrubs (24 species) and on ornamental coniferous trees and shrubs (8 species) in parks, botanic and household gardens, housing settlements and along avenues. The most numerous and economically important species is Parthenolecanium corni, followed by Carulaspis juniperi and Leucaspis lowi. Special attention should be paid to invasive Pulvinaria floccifera on Ilex aquifolium (L.) and unidentified Parthenolecanium sp. on rhododendron plants. These scale insects were observed in massive density on their hosts and can survive the winter in Poland.

Edible flowers have been used in traditional and herbal medicine since ancient times, but its nutritional value have not been studied in depth. The lavender-pink globular flower heads of chive not only beautify the garden or dried bouquets, but they can also be used to prepare chive vinegar, salads or soups. The aim of this work was to determine the nutritional value of flowers of the chive cultivated at the Horticultural Experiment Station in Dołuje (north-western Poland) in the years 2009 and 2010. In the raw plant material, the content of dry matter, total ash, total protein, titratable acidity, vitamin C as L-ascorbic acid, total and reducing sugars, fat, crude fibre, polyphenols, total carotenoids, chlorophylls, pungency, free radical scavenging activity and energy value were measured. The Allium schoenoprasum L. dried flowers were extracted by ethanol at 50°C and at room temperature (maceration). The obtained extracts were analyzed by GC-MS method. The analysis revealed that the flowers contained much important fatty acids with palmitic acid (7.94–16.94%), linoleic acid (7.63–13.45%) and stearic acid (3.13–31.16%), the most abundant saturated and unsaturated fatty acids, as well as γ-sitosterol (3.41–6.42%), campesterol (0.34–0.66%), fucosterol (0.29–0.51%) and vitamin E (0.16–0.49%). Moreover, in the dry plant material content of total flavonoids was assessed.

Prunus domestica L. is the most important fruit crop in the Europe and the most important within the genus Prunus. Serbia is the third world producer, after USA and China, of that friut. The seven F₁ plum genotypes (Prunus domestica L.) which originated from three cross-combinations (‘Č ačanska Lepotica’ ב Stanley’, ‘Č ačanska Najbolja’ ב Stanley’, ‘Stanley’ ב Stanley’) and these cultivars as controls were planted in the experimental orchard in Prislonica, near Cacak, in spring 2000. In 2005–2007 several biological (blooming period, harvest date and yield) and main fruit quality traits were evaluated. Considerable variation was observed among the F₁ genotypes, i.e. cross-combinations. All genotypes begun blooming later than their parents. The earliest harvest date was observed in ‘P₄’ and the latest in ‘P₇’. The highest yield was observed in ‘P₅’. The genotype ‘P₄’ had better values for some fruit quality traits (fruit weight, fruit rate, flash rate, fruit height, suture diameter, cheek diameter, soluble solids, fructose and total sugars content), when compared with other F₁ genotypes and control cultivars. The genotypes with better biological and fruit quality traits were included in the ‘Č ačanska Lepotica’ ב Stanley’ cross-combinations.

Induced mutagenesis allows to obtain in relatively short time new cultivars of chrysanthemum differing in single characteristic traits such as the colour or shape and size of inflorescence, which determines their decorative values. The traditional breeding methods as crossing, selection and techniques of genetic transformation face limitations in this species. The object of investigation were three cultivars of Chrysanthemum × grandiflorum (Ramat.) Kitam. –‘ Albugo’, ‘Alchimist’, ‘Satinbleu’. Gamma radiation in dose of 15 Gy was obtained from Co⁶⁰ cobalt source generated by Theratron 780 C. The dose rate was 2.14 Gy × min^-1. ‘Albugo’ and ‘Satinbleu’ microcuttings cultured on MS medium were exposed to irradiation. Following the irradiation, single-node explants and leaves were excised from plantlets and subcultured onto MS medium supplemented with 0.6 mg × dm^-3 BAP and 2.0 mg × dm^-3 IAA. In ‘Alchimist’ there were irradiated leaf explants with callus regenerated on petioles. A month earlier this explants were placed on the MS medium with 0.6 mg × dm^-3 BAP and 2.0 mg × dm^-3 IAA added. The regeneration of adventitious shoots was conducted without subculturing onto fresh medium. Newly formed shoots were transferred onto rooting medium 4 months after the irradiation. Gamma radiation effected the regeneration of shoots on explants. From the mutants obtained in vM₂ generation the most interesting, worth introducing to cultivation five genotypes were selected: ‘Albugo Sunny’, ‘Alchimist Tubular’, ‘Alchimist Golden Beet’, ‘Satinbleu Minty’, ‘Satinbleu Honey’.

For the intensive planting system production of apple fruit orchard, the ideal tree is one that does not grow too vigorously, presents early and constant bearing, and is able to produce high quality fruits. Our experiment was to assess eighteen rootstocks of different origin and vigour for ‘Elise’ planted in the “V” system. The field experiment was established in 2000, in the experimental orchard of the Department of Pomology, Warsaw University of Life Sciences, Wilanów. The influence of eighteen rootstocks on orchard performance of ‘Elise’ apple trees was investigated in the years 2000–2009. Different rootstocks were classified into three groups depending on expected tree vigour: superdwarfing (M.27, P 16, PB 4), dwarfing (B 9, B 146, P 2, P 59 and seven subclones of M.9: EMLA, Burgmer 984, Burgmer 751, T 339, Pajam 1, Pajam 2, RN 29), and semi-dwarfing (P 14, M.26, P 60, B 396). Trees on rootstocks assumed as superdwarfing were spaced at a distance of 3.2 × 0.5 m, on dwarfing at 3.5 × 0.7 m and on semi-dwarfing at 3.8 × 1.0 m. The smallest trunk cross-sectional area (TCSA) after 10 years, as well as the increase of TCSA for 2000–2009 among superdwarfing rootstocks was on PB 4, whereas among dwarfing rootstocks was on P 59. Among trees on semi-dwarfing rootstocks the highest TCSA as well as the increase of TCSA was on P 14. The highest cumulative yield per tree among superdwarfing rootstocks (2001–2009) was obtained on P 16, whereas the lowest on PB 4. On rootstocks considered as dwarfing, the lowest cumulative yield was observed on P 59, and the highest on M.9 751. The highest cropping efficiency coefficient (CEC) on super-dwarfing rootstocks was observed on P 16, on dwarfing rootstock on P 59 and on semi-dwarfing rootstock on P 60 and B 396.

In case of sulphur shortage in the soil that element has a significant impact on yields of plants and their quality. The objective was to assess the impact of the work and the kind of sulphur content of Cu, Zn, Mn and Fe in the dry mass and uptake these elements by yield of dry mass of potato tuber. Experience in the field of potato head was in the years 2004–2006 by applying different kinds of sulphur (elemental and K₂SO₄) and dose (0, 25 and 50 kg·ha^-1). Sulphur indeed affected the application to increase the yield of tubers. However, there has been an independent impact dose and kind of sulphur of tested characteristics. Only in the case of interaction of dose and kind of sulphur fertilization it was found that the highest yield was found when using 25 kg∙ha^-1 in the sulphate kind and 50 kg∙ha^-1 S in sulphate and elemental kind. The yield of dry mass was greatest when applied 25 kg∙ha^-1 in the sulphate kind. The content of Cu, Zn, Mn (except Fe) in the dry mass and uptake these elements by yield of dry mass of potato tuber was significantly determined by S fertilization. The highest content of Cu and Zn in the dry mass and uptake these elements by yield of dry mass of tuber was after applying 50 kg S∙ha^-1 in elemental kind and on the control plots (without sulphur). Content and uptake of Mn by tuber was reduced by sulphur fertilization, and the contents and uptake of the Fe by tuber increased as a result of increasing doses of sulphur (although not confirmed that statistically). Elemental sulphur in dose 50 kg∙ha^-1 substantially reduced the pH value of the soil. It was a significant correlation between the pH value of the soil and the contents of Cu (negative), Zn (positive) and Mn (different values depending on years of research) in the dry mass and uptake these elements by yield of dry mass of potato tuber.

Abstract: The quantity of weeds depends on biotopic factors, on the supply of seeds in the soil and agrotechincal procedures, which stimulate or inhibit weed germination and development. Intercrop plants applied in contemporary systems, modifying the soil environment, also influence the weed infestation of crops. The aim of conducted studies was to determine the effect of intercrop plant application and kind of ploughing upon the state and degree of Spanish salsify weed infestation. In the field experiment with growing Spanish salsify (Scorzonera hispanica L.) the following intercrop plants were applied: common vetch (Vicia sativa L.), tansy phacelia (Phacelia tanacetifolia Benth.), oat (Avena sativa L.), as well as differentiated soil tillage: conventional plough cultivation with pre-winter mouldboard ploughing without intercrop; intercrop plant sowing plus deep pre-winter ploughing; intercrop plant sowing plus spring ploughing. In Spanish salsify weed infestation jointly 37 taxons of weeds were determined, among which the most numerously occurred: Chenopodium album L., Senecio vulgaris L., Capsella bursa-pastoris (L.) Med., Lamium amplexicaule L., Galinsoga ciliata (Raf.) S.F. Blake and Urtica urens L. The numerical force of primary and secondary Spanish salsify weed infestation after pre-winter and spring ploughing was similar. Intercrop plants significantly limited the primary and secondary weed infestation of this plant. The smallest quantities of weeds grew in objects where oat was the intercrop plant, and the largest – in cultivation without intercrops. Intercrop plants limited the occurrence of Senecio vulgaris and Capsella bursa-pastoris in primary weed infestation, and oats intercrop also limited the occurrence of Lamium amplexicaule and Senecio vulgaris in secondary weed infestation of Spanish salsify.

Salsify has a remarkable taste and nutritious values. It is a rich source of inulin – a glycoside which has a positive effect on human and animal organisms. The paper presents studies on the species composition of soil-borne fungi infecting the roots of Tragopogon porrifolius var. sativus cultivated with the use of oats, tansy phacelia and spring vetch as cover crops. In a field experiment the cover crops formed abundant green mass before winter and it constituted a natural mulch on the surface of the plough land. It was managed in two ways: 1) mixed with the soil as a result of spring ploughing, or 2) mixed with the soil as a result of pre-winter ploughing. The conventional cultivation of salsify, i.e. without cover crops, constituted the control. The studies established the number and health status of four-week-old salsify seedlings and roots with necrotic signs. A laboratory mycological analysis made it possible to determine the quantitative and qualitative composition of fungi infecting the underground parts of Tragopogon porrifolius var. sativus. The emergences and the proportion of infected salsify seedlings varied and depended on the species of the mulching plant. The smallest number of infected seedlings was obtained after the mulch with oats, slightly more after the application of spring vetch or tansy phacelia as cover crops, and the most in the control. Regardless of the species of the mulching plant, the following were frequently isolated from the diseased seedlings and roots of salsify: Alternaria alternata, Fusarium culmorum, Fusarium oxysporum, Penicillium spp., Rhizoctonia solani and Sclerotinia sclerotiorum. Rhizoctonia solani and Sclerotinia sclerotiorum proved to be the most harmful towards the roots of salsify. The system of cultivation, i.e. performing spring or pre-winter ploughing, had no significant effect on the total population of fungi.

Iron chlorosis is a wide-spread limiting factor of production in agriculture. Fe deficiencies is done mainly by foliar sprays because soil application generally are ineffective, especially for annual crops. A pot experiment, conducted in a phytotron, investigated the effectiveness of foliar fertilization of French bean with 3 inorganic iron salts [FeSO₄ · 7H₂O, FeCl₃ · 6H₂O, Fe(NO₃)₃ · 9H₂O] and 2 organic iron salts [Fe-Citr., Fe-EDTA], applied with and without the addition of 0.5% CO(NH₂)₂. Iron was applied 3 times only on simple leaves in the form of aqueous solutions containing 0.2 mg Fe in 1 cm³, compared to water as the control treatment. The obtained results show that the application of iron salt solutions resulted in a distinct increase of Fe content in simple leaves and in the next trifoliate leaves. Foliar fertilization of the plants with Fe(NO₃)₃ was the most effective, while feeding with Fe-EDTA was the least effective. Iron given in the form of chelates showed greater mobility in the plants than that applied in the form of inorganic salts. Foliar fertilization of the plants with inorganic iron salts significantly increased chlorophyll a+b and carotenoid content in the leaves as well as their stomatal conductance and the photosynthesis and transpiration rates. But the impact of Fe chelates, in particular Fe-EDTA, on the abovementioned plant traits was not clear. The leaves of the plants treated with Fe(NO₃)₃ showed the highest content of photosynthetic pigments and the most intense gas exchange. The application of inorganic iron salts and Fe-Citr. resulted in a significant increase in the number of nodules formed on the bean roots and their weight. The plants treated with Fe-Citr. produced the largest number of nodules, while those treated with Fe(NO₃)₃ developed nodules with the highest weight. The addition of urea to the iron solutions had an effect on the increase in the value of the iron transport rate and on the decrease in iron and carotenoid content, the leaf gas exchange rate as well as the number of root nodules and their weight.

The aim of the study was to evaluate cellulolytic and amylolytic enzymes activities in substrates, regarding the time of the Pleurotus ostreatus (Mori Hiratake no 39) B7 mycelium incubation, and the stage of physiological development. The experiment was divided into three parts which had different times of mycelium incubation before fructification: I – the time of incubation – 2 weeks; II – 4 weeks; III – 6 weeks. After the mycelium incubation, cold-shock and mechanical-shock was provided on each series. Researches proved that agents such as the time of mycelium incubation in substrate, agrotechnical treatment (cold-shock, mechanical-shock), and the type of mycelium layer had an impact on cellulolytic and amylolytic activity of mycelium in the cultivation’s substrate. The biggest influence on change of enzymatic activity had agrotechnical treatment: cold-shock and mechanical-shock.

Breeding of stone rootstock is very important problem for orcharding. In many countries of the world have been obtained a lot of new breeding material for sweet and sour cherries and plums. An analysis was conducted in Cacak (Western Serbia) in the 2006–2007 period to examine major morphological traits of the aerial part and root of suckers derived from mother bushes of three newly vegetative rootstocks for stone fruit species, particularly plum, peach and apricot trees. The newly breed rootstocks have been developed from autochthonous genetic material, their specific designations being: FA 2/53 (Prunus domestica L.), FA 5/7 (P. domestica L.) and FA 6/209 (P. cerasifera Ehrh.). The analysis of suckers of the new rootstocks included the investigation of morphological traits through the determination of: a) length of the aerial part, b) number of feathers on aerial part, c) number of roots, d) length of roots, and e) volume, weight and category of the roots. They developed branch roots and exhibited good length of the aerial part, a substantial number of roots and root dry weight. The FA 2/53 rootstock can be classified into low-vigour rootstocks, FA 5/7 into low to moderately vigorous ones (slightly more vigorous than the FA 2/53 rootstock) and FA 6/209 into moderately vigorous rootstock for stone fruits.

Fungi belonging to Phoma spp. commonly occur on herbaceous plants, including herbal ones. In the years 2004–2006 isolates belonging to genus Phoma which were differentiated in morphological respects were obtained from herbs belonging to family Lamiaceae. Basing on constant morphological feature observed in vitro in the cultures developing on standard media, isolates of Phoma spp. were included within the proper section, and next the species were identified. P. exiqua var. exiqua was isolated from all parts of the examined plants. P. nepeticola cultures were obtained from the leaves and stems of motherwort, whereas isolates of P. nemophilae were from the roots. Apart from the above mentioned species, P. capitulum, P. labilis, P. pereupyrena, P. subglomerata and P. septicidalis were also isolated.

The paper presents a procedure to identify promising, chilling-insensitive cucumber genotypes from a pool of 55 breeding lines. Selected genotypes may constitute valuable material in further selection of high-yielding cultivars in moderate climate. The approach is based on determining nitrate (NO₃^–) content, nitrate reductase activity (NRA) and chlorophyll content (Chl) in cotyledons of cucumbers grown at 12^oC. These observations were then used to develop a simple algorithm, which facilitates the ordering of genotypes according to their chilling sensitivity by assigning them ranks on the basis of quartile values (from 1 to 4) of determined traits. From the examined collection, 14 least chilling-sensitive genotypes were selected, i.e. their selection for further breeding carries the lowest risk. Low chilling sensitivity of the above mentioned 14 cucumber genotypes was manifested by high Chl levels and high NRA as well as high NO₃^– contents, i.e. the sum of quartile ranks ranged from 10 to 12, at a maximum of 12. Then cluster analysis was applied to select genotypes, which possess desirable levels of tested traits. Cluster analysis showed that at the division into two and into three subsets all the 14 genotypes considered promising were found within the same cluster, when these genotypes were divided into more subsets, 13 out of the 14 best genotypes were found in one cluster. The presented method may be used to select the least chilling-sensitive cucumber genotypes also from other collections. Knowing the quartile values calculated on the basis of presented results, the rank of new genotypes characterizing their chilling sensitivity may be estimated, provided that experiments are carried out under conditions similar to those used in this study. Otherwise the application of this algorithm has to be preceded by an in-depth explorative analysis and the determination of new quartile values for the analyzed traits.

Marigold belongs to the oldest medicinal plants, which had been used in the ancient times. At present it supplies its material of a great significance for pharmaceutical and cosmetic industry. The study was conducted in the period 2007–2009 on loess soil with the granulometric composition of silt loam. The aim of the experiment was to determine the effect of different nitrogen doses (0, 40, 80, 120, 160 kg N∙ha^-1) on some plant morphological features as well as on yield and quality of pot marigold inflorescences. Flowering of pot marigold was shortest in the control treatment (30 days) and longest (40 days) in the plot where nitrogen fertilization had been applied at the highest rate (160 kg N·ha^-1). Nitrogen fertilization had a significant impact on the number of flower heads per plant, but no differences were found in inflorescence diameter under investigated factor. Raw material yield was found to increase significantly after the application of 80 kg N·ha^-1, compared to the control treatment. Further increase in the amount of nitrogen (120, 160 kg N·ha^-1) did not result in growth of yield. Nitrogen fertilization modified essential oil content in flowers heads (this content increased along with increasing nitrogen rates), but it did not affect the percentage of flavonoid compounds.

Zucchini (Cucurbita pepo L. var. giromontina) is a dependable vegetable in cultivation which is characterized by high fertility. Grown in the field and under cover, it is infected by a number of pathogens specific of the family Curbitaceae as well as those that are characteristic of other plantations. Actually, natural products such as plant extracts are more and more frequently used in plant protection from pathogens. The azoxystrobin (Amistar 250 SC, Syngenta) and extract of grapefruit (Biosept 33 SL, Cintamani Poland) were tested in vitro for their effectiveness to inhibit the linear growth of Alternaria alternata, Botrytis cinerea, Fusarium avenaceum, F. culmorum, F. equiseti, F. oxysporum, Rhizoctonia solani and Trichoderma hamatum. The azoxystrobin (0.05%, 0.1%) and extract of grapefruit (0.1%, 0.2%) were applied in different concentrations. The studies made use of a Petri dishes method recommended for testing fungicides in laboratory conditions. Extract of grapefruit was more effective than azoxystrobin. The extract of grapefruit inhibited the growth of A. alternata, B. cinerea, R. solani and T. hamatum already after 4 days and was the most effective after 12 days of experiment. Azoksystrobin inhibited the growth of B. cinerea and R. solani but did not inhibit the growth of F. equiseti. Microscopic analysis showed the morphological changes in fungal hyphae under the influence of tested substances.