Arugula is a common name for several leafy vegetable species of the family Brassicaceae. Eruca sativa and Diplotaxis tenuifolia are grown commercially for human consumption. The effect of two types of flat covers, perforated PE film and non-woven PP fabric, on the yield and quality of arugula was determined in the study. A two-factorial experiment was conducted in 2006–2008 in the Experimental Garden of the University of Warmia and Mazury in Olsztyn. The first experimental factor was plant species – Diplotaxis tenuifolia and Eruca sativa. The second factor was the type of plant cover – perforated PE film with 100 openings per m² and non-woven PP fabric with surface density of 17 g·m^-2. Plants grown without protective cover served as control. Arugula was grown on proper black earth soil of quality class IIIb and cereal-fodder strong complex. Each year, seeds were sown in the middle of April. After planting out in the field, the seedlings were covered with PE film and non-woven PP fabric. The covers were removed after approximately five weeks. Leaves were harvested gradually over the growing season, one to three times from each treatment. The use of PE film and non-woven PP fabric covers had a significant effect on the total and marketable yield of arugula leaves. In 2006–2008, the highest average total yield was obtained from plots covered with perforated PE film. The marketable yield had a higher share of the total yield in Diplotaxis tenuifolia and in plots covered with perforated PE film, compared with control plots and plots covered with non-woven PP fabric. The rosettes of Diplotaxis tenuifolia consisted of a higher number of leaves, while Eruca sativa had longer leaves and higher rosette biomass.

Dense trees planting is one of the ways to obtain high yielding from area unit soon after establishing an orchard. Diminished space occupied by trees in dense planting systems also brings about their weaker vegetative growth. Another factor influencing growth and yielding is planting trees in ridges. Investigation was conducted in the orchard belonging to Research – Development Station in Samotwór, owned by Department of Horticulture at Wroclaw University of Environmental and Life Sciences. It aimed at the assessment of growth and yielding of four apple cultivars: ‘Piros’, ‘Sunrise’, ‘Pinova’ and ‘Ligol’, growing on two dwarf rootstocks M.9 and P 22. The trees were planted in ridges in high density. Two – year – old trees were planted in the spring 2004. Research covered the years 2004–2008 and was carried out as two – factorial experiment. The first factor involved particular way of planting trees – traditional or in ridges. The type of rootstock used constituted the second examined factor. The trees on M.9 rootstock were planted in 3.5 m × 0.5 m spacing (5714 trees·ha^-1), while apple trees on P 22 rootstock followed the spacing of 3.5 × 0.3 m (9523 trees·ha^-1). In the case of young trees growing densely, the effect of planting in ridges on growth and yielding was strictly related to apple cultivar and rootstock. Among the trees on M.9 rootstock, the highest yield was collected from cultivar ‘Ligol’. The trees of ‘Piros’ cv., planted in ridges provided the lowest yield on both used rootstocks. The negative effect of ridges on total yield for ‘Ligol’ and ‘Sunrise’ cvs. on M9 was noted. No differences were observed in the total yield from trees of ‘Pinova’, ‘Ligol’ i ‘Sunrise’cvs. on rootstock P 22. Method of planting had no effect on the yield of each cultivar on this rootstock. Cultivar ‘Ligol’ on M.9 rootstock, characterized the strongest growth. Among the trees on rootstock P 22, cultivar ‘Sunrise’ grew the weakest. Planting in ridges, reduced the growth of ‘Ligol’ on M.9 and ‘Piros’ cvs. on P 22 rootstock. Dense planting of trees in ridges did not affect yield and vigour of four cultivars of apple trees on two dwarfing rootstocks. In the conditions of high density trees response to planting in ridges was diverse and depended on a cultivar, the kind of a rootstock and the age of trees. Dense planting of trees in ridges did not provide favorable conditions for growth and fruiting of the examined apple trees cultivars in the first five years after planting.

The leaves of lettuce are very reach source of vitamins, macro and microelements and biologically active compounds. However, these plants contain also anti-nutritional compounds as nitrates and nitrites which levels depend on growth and storage conditions. The aim of this study was to determine the effect of foliar application of CaCl₂ treatment before harvest on nitrate and nitrite accumulation, in whole leaves and leaf blades in fresh and stored lettuce. The experimental material was lettuce cv. Omega which was grown in greenhouse. The solution of CaCl₂ was used in the concentration of 0.1M and 0.2M on plants, 20 and 10 days before harvest. After harvest, some plants were directly analysed, while the remaining plants were cold-stored at 4ºC for 7 and 14 days in dark polyethylene bags. The higher concentrations of nitrate and nitrite was noticed in fresh whole leaves than in leaf blades. The foliar CaCl₂ treatment of plants before harvest contributed to a statistically decrease in the nitrate levels and nitrite increase in whole leaves in fresh plants. The greatest changes were noticed after using of 0.1M CaCl₂ solution on plants. During the storage time of lettuce in the non-treatment plants were observed the higher concentration of nitrates and nitrites in leaf blades compared to fresh plants. The CaCl₂ treatment on lettuce caused a significant decrease in the nitrite concentration of whole leaves of plants stored for 7 days, while in the leaf blades higher nitrite amounts were accumulated in lettuce which was stored in cold conditions during all experimental time.

Iodine is not an essential nutrient for plants. Side-effects of its application on mineral nutrition of plants have not yet been thoroughly documented. The aim of the study was to evaluate the influence of soil application of iodine and sucrose on accumulation of heavy metals and trace elements in spinach. In 2009–2010, a pot experiment was carried out with spinach Spinacia oleracea L. ‘Olbrzym zimowy’ cv. cultivated on mineral soil. The research included diverse combinations with pre-sowing iodine fertilization (in the form of KI) and soil application of sucrose: 1) –control (without iodine fertilization and sucrose application), 2) –1 mg I dm^-3 of soil, 3) –2 mg I dm^-3 of soil, 4) –1 mg I + 1 g sucrose dm^-3 of soil and 5) –2 mg I + 1 g sucrose dm^-3 of soil. In spinach as well as soil after its cultivation the content of 29 elements was determined by ICP-OES technique, including: Ag, As, Be, Bi, Cs, Dy, Er, Eu, Hg, Ho, In, Li, Lu, Ni, Pb, Pr, Sb, Sc, Sm, Sn Sr, Tb, Th, Ti, Tl, Tm, V, Y and Yb. A significant influence of iodine fertilization as well as its interaction with sucrose was found in respect of: Li, Ni, Pb, Sr, Ti, Y, V, Ag, Lu, Sc, Tb, Th, Yb, Dy and Sn level in spinach leaves. Fertilization with iodine only (in both tested doses) contributed to a significant increase in V, Sc and Th as well as reduced Ag content in spinach when compared to the control plants. Application of the higher iodine dose (2 mg I dm^-3 of soil) resulted in greater accumulation of Pb and Sn in spinach as well as lowered Sr concentration in comparison to plants treated with 1 mg I dm^-3. Simultaneous application of iodine (in both doses) and sucrose decreased spinach content of: Li, Ni, Pb, Sr, Y, V, Sc, Tb and Yb when compared to the control object as well as plants fertilized only with iodine. In the case of Li, Y, V, Sc and Tb, a stronger influence was found for sucrose applied together with the higher dose of I. Obtained decrease in Sr, Y, Sc and Tb accumulation in spinach (after iodine and sucrose application) correlated with lower soil content of these elements.

Iodine biofortification of vegetables can become an alternative (to iodized salt) method of introducing this element into human diet. Development of agronomic rules concerning its application requires detailed evaluation of iodine influence on plant physiological and biological processes including mineral nutrition and quality of yield. The aim of the study was to determine the effect of iodine and soil application of sucrose on iodine biofortification and nutritional quality of spinach plants. In 2009–2010, a pot experiment was carried out with spinach Spinacia oleracea L. ‘Olbrzym Zimowy’ cv. cultivation on mineral soil. The research included diverse combinations with pre-sowing iodine fertilization (in the form of KI) and soil application of sucrose: 1) –control (without iodine fertilization and sucrose application), 2) –1 mg I dm^-3 of soil, 3) –2 mg I dm^-3 of soil, 4) –1 mg I + 1 g sucrose dm^-3 of soil and 5) –2 mg I + 1 g sucrose dm^-3 of soil. In all tested combinations with iodine fertilization as well as simultaneous application of iodine and sucrose a significant increase in iodine, N-total and soluble oxalate content was observed along with reduced level of nitrate(V) and dry matter in spinach leaves (when compared to the control). The highest accumulation of iodine was noted in leaves of plants treated with 2 mg I + 1 g sucrose dm^-3. Simultaneous application of iodine and sucrose diminished free amino acid content in comparison to the control. Additional introduction of sucrose along with both iodine doses decreased nitrate(V) and N-total level in spinach plants. Soil fertilization with both doses of iodine (1 and 2 mg I dm^-3 of soil) applied individually or together with sucrose did not significantly affect spinach yield and the level of nitrate(III), phenolic compounds and soluble sugars in plants as well as iodine content in soil after cultivation.

Gardenia is an ornamental shrub or small tree that has thick dark evergreen leaves and fragrant flowers of white colour. It is used as a garden plant in the mild climate as well as a flowering potted plant. Many studies have been taken to propagate gardenia in vitro and to reduce the time necessary for the introduction of new cultivars. The present study investigated the effect of different light qualities (white, blue, yellow, red) on shoot and root development and growth of Gardenia jasminoides Ellis. Shoot tips were obtained from aseptic in vitro cultures and explants were cultured on modified Murashige and Skoog medium containing BA at 5 or 25 µM as well as on medium without growth regulators. The experiment lasted 6 weeks and was repeated twice. The promoting effect of yellow light on the length of the main shoot growing on control medium was noted. There was no significant effect of different light qualities on the number of axillary shoots obtained from tip shoots cultured on growth regulator-free medium. Yellow light increased the number of axillary shoots from explants cultivated on medium containing 25 µM BA and it promoted shoot elongation most strongly on medium with the addition of 5 µM BA. Red and yellow light increased the number of roots on control medium, whereas yellow light significantly promoted root elongation growth. However, yellow and white light had the most positive effect on the average fresh weight of roots.

The influence of four cytokinins: BA (4.4, 11.1, 22.2 µmol·dm^-3), kinetin (4.7, 11.6, 23.3 µmol·dm^-3), 2iP (4.9, 12.3, 24.6 µmol·dm^-3), TDZ (4.5, 11.4, 22.7 µmol·dm^-3) on shoot multiplication of Rheum rhaponticum ‘Karpow Lipskiego’ on Murashige and Skoog (MS) medium was studied. The shoots used in the experiment were obtained from aseptically grown shoot clusters. Rooted shoots (except treatment with TDZ) after acclimatization were transplanted to pots into a peat substrate where they were grown for 4 weeks. Plants were then cultivated in the field for 8 months. During in vitro studies the cytokinins promoted the development of leaves as well as the formation of new shoots. The highest average number of axillary shoots was found on the medium with BA 11.1–22.2 µmol·dm^-3. The use of kinetin (4.7–11.6 µmol·dm^-3) or 2iP 12.3 µmol·dm^-3 stimulated strong growth of shoots expressed in their length and size of the leaf blade. All TDZ concentrations caused a significant inhibition of shoot elongation. BA and TDZ had a harmful effect on the rooting of multishoots. On the control medium (hormone-free) and on the media containing kinetin or 2iP, 100% of shoots produced roots. After a period of 8 months, following overwintering and start of vegetation growth, the plant survival rate was 80–100%. It was found that 2iP 12.3 µmol·dm^-3 had the highest after effect on plant growth. The plants derived from this medium had uniform and compact growth and they developed more leaves in the rosette with significantly larger laminae as well as longer and thicker petioles, than plants obtained from others used media.

The mycobiota composition of plant phyllosphere depends on atmospheric factors as well as on the physiological properties of plant. In the recent years the infections of the eastern purple coneflower by Sclerotinia sclerotiorum, Botrytis cinerea, Fusarium oxysporum, Verticillium dahliae and by Erysiphe cichoracearum have been observed. The development of these pathogens is dependent on the species composition of the phyllosphere organisms, but it is also affected by the form and the level of nitrogen nutrition. The undertaken study aimed at the analysis of the mycobiota composition of the coneflower phyllosphere as dependent on the rate of ammonium sulphate used in the plant fertilization. The experiment was set up in 2007–2009 at Psary near Wrocław. Two fertilizer rates were applied: 50 kg N·ha^-1 and 200 kg N·ha^-1. The fungal taxa most abundantly isolated from the leaf surface of coneflower are: Cladosporium spp., Alternaria alternata, yeast-like colonies, Fusarium spp. and Epicoccum nigrum. These fungi make up > 90% of the isolated colonies., with C. herbarum and A. alternata as the dominant components of the assemblages. The dominant species within Fusarium spp. is F. equiseti. The species composition of the assemblages of fungi in the coneflower phyllosphere is variable and dependent on the course of the weather. The fertilization rate of ammonium sulphate does not affect the species composition of the phyllosphere fungi assemblages of the coneflower.

In many ornamental plant species the light spectrum can, to a varied extent, modify growth and flowering. The literature offers information on the inhibition of growth of seedlings and cuttings of ornamental plants exposed to blue light. In this paper was investigated the effect of light of a varied spectral composition on the growth of scarlet sage (Salvia splendens) seedling. The plants were cultivated in the growth chamber at the 16-hour and 20-hour day. The following kinds of light were used: daylight – similar in its spectral composition to natural light, blue and mixed light – with the same share of daylight and blue light as well as with 75% share of blue light. The intensity of the quantum irradiance in the range PAR was the same for all the experiment combinations and it was 110 μmol · m^-2 · s^-1. The scarlet sage grown in mixed light with the advantage of blue light was lower than the plants produced in daylight both at the 16-hour and 20-hour day.

Fungi Trichoderma spp. are present in nearly all soils and other habitats. Most of Trichoderma strains are efficient for control of some pathogens. Some strains induce plant native defence mechanisms. Botrytis cinerea [Pers.: Fr.] causes economic losses on a wide range of cultivated plants and stored fruits. In presented work Trichoderma asperellum [strain T1] isolated from commercial product was selected to apply in the field experiments. The trade bioproduct containing 5 × 10⁸ of Trichoderma conidium per one gram was used in organic field strawberry. Treatments with microorganism-antagonist at concentration 10 g · l^-1 were performed as a foliar spraying, three times during the growing season. Applied Trichoderma caused bigger and more vigorous growth. The insignificant presence of B. cinerea on harvested and stored fruits was found. The possibility of use of T. asperellum as biological control agent for post-harvest diseases and for prolongation of time storage was observed until 7 days after harvest. In the second season of research, statistical significantly higher yield of the treated plants (30.2%) was obtained compare to the untreated plants. Also the weight of aboveground part of plants (24.0%) and number of runners were increased.

Grasses are very often infected by endophytic fungi of the Neotyphodium and Epichloë genera. They can produce metabolites toxic to livestock as well as beneficially affect grasses. Thus, endophytes can be used for plants improvement. These facts stimulated a more detailed investigation aimed at providing more insight into the problem of these endophytes in Poland. The aims of the research were as follows: (i) to determine the levels of colonization of Polish-grown cultivars of perennial ryegrass, meadow fescue, and red fescue with endophytic fungi of the genera Neotyphodium and Epichloë; (ii) to determine the potential hazards associated with the toxins produced by the active associations; (iii) to isolate viable endophytes of the genera Neotyphodium and Epichloë from active associations; and (iv) to determine the levels of antagonistic activity of the obtained endophyte isolates against selected microorganisms, in particular serious grass pathogens, in vitro. The staining method was used for endophytes detection in grass seed collection. Endophytes were isolated on PDA medium and characterized. Antagonistic activity of N/E isolates and seed extracts were determined in dual culture assays and on microscope slides respectively. Ergovaline and lolitrem B content were assayed. There were 242 samples of seeds of 50 cultivars of grasses collected in Poland, including 124 samples of 20 cultivars of perennial ryegrass, 61 samples of 10 cultivars of meadow fescue, and 57 samples of 20 cultivars of red fescue. Endophytic fungi were only detected in 33 seed samples of 5 perennial ryegrass cultivars and in 15 samples of 2 meadow fescue cultivars. The levels of seed colonization of these species reached maximum 8 and 90%, respectively. No colonization by endophytes was found in seeds of red fescue. The viability of endophytic mycelium in the seeds of perennial ryegrass and meadow fescue was very low. Endophytic fungi were isolated only from 3 and 4 samples of these grasses respectively. In laboratory conditions, endophytic fungi showed stronger antagonistic properties at 25°C. The highest and most frequent growth inhibition was observed for M. nivale, Rhizoctonia solani, Fusarium avenaceum and F. equiseti. The obligate pathogens B. graminis, P. coronata, and P. graminis ssp. graminicola were not sensitive to water and alcohol extracts of E+ seeds. Isolates Fp28, Fp40, and, to a lesser degree, Fp37, originating from meadow fescue, were characterized by the strongest antagonistic properties. Moreover, they did not produce (Fp28 and Fp37), or produced only small amounts (Fp40) of, ergovaline, which is toxic to animals. After additional tests, they could be used as biological factors for improving the utility value of new grass varieties and their resistance to stress factors.

In the intensive tomato production under covers, the soilless cultivation dominates. The objective of this study was to assess some quality traits of cherry tomato and middle fruit size tomato, concerning their chemical composition and sensory attributes as well as their correlation to growing medium and harvest time. Cherry tomato (Dasher F₁ and Organza F₁) and middle fruit size tomato (Admiro F₁ and DRW 7594 F₁) cultivars were grown in the years 2008–2009 in the greenhouse with controlled climate and drip fertilizing system, in three different growing media. Organic media – coconut fiber and wood fiber were compared to rockwool, commonly used as a standard horticultural medium. The quality traits that mostly differentiated tomato fruits were the cultivar, harvest time and to the lesser degree the medium quality. Tomatoes harvested in July had a higher sugar content and received a higher sensory evaluation than those harvested in September. The sugars to acids ratio was the highest in fruits grown on coconut fiber. These fruits also obtained higher notes of particular determinants of sensory analysis, especially tomato flavor. The highest quality in respect to the content of the investigated chemical components and sensory evaluation was observed in fruits of Dasher F₁ and Admiro F₁ cultivars. A significant correlation between the content of chemical quality attributes of tomato fruit with such determinants of sensory evaluation as skin firmness, tomato and sweet taste was revealed. Sugar in fruits was positively correlated with the overall tomato assessment. Firmness and sweet taste were significantly correlated with organic acids and soluble solids contents.

Root crops are particularly sensitive towards growth conditions, while simplifications recommended at present in agricultural technology exert diverse effects on reactions of cultivated plants. The study aimed at evaluating the impact of varied tillage systems and plant cultivation as well as foliar cooper and manganese nutrition on root yields of scorzonera and some of their qualitative traits. The field experiments were carried out in 2005–2007 on lessive soil developed from loess formations covering the chalky marls. Scorzonera of Duplex cv. was the testing plant. The experimental pattern included the following factors: two plant cultivation methods (on flat soil and on ridges), two pre-sowing tillage systems (harrowing, rototiller), as well as foliar nutrition with copper and manganese. The highest total and marketable yields of scorzonera roots at the lowest share of non-commercial roots in total yield, was achieved due to cultivation in ridges, after pre-sowing tillage using rototiller, and manganese foliar nutrition. The positive influence of scorzonera cultivation on ridges on dry matter content in roots was recorded. Diverse tillage systems and plant foliar nutrition had no significant effects on inulin content in scorzonera roots; however the increasing tendency of the component concentration at plants cultivated on ridges after shallow spring tillage procedures, was observed. Studied experimental factors did not exert any considerable influence on protein contents in scorzonera roots.

Pears, besides apples, are also popular fruit species at the Polish fruit market. It is connected not only with their delicious taste but, among others, year-round availability at the market. The research objective was to determine and compare the basic chemical composition, i.e. dry matter, N-compounds (total), mineral elements (total), dietary fiber and easily hydrolyzed sugars (NFE), vitamin C as well as mineral content of: Mg, K, Na, Ca, Mn and Fe in the flesh and the peel of pears of the following cultivars: ‘Bonkreta Willimsa’, ‘Concorde’, ‘General Leclerc’, ‘Faworytka’, ‘Komisówka’, ‘Konferencja’ and ‘Lukasówka’ harvested in 2009 and 2010. In all the analyzed pear cultivars, nutrient concentration appeared to be higher in the fruit peel compared to the flesh. The pears from the ‘Concorde’cv (average 23% f.m. –dry matter, 0.5% f.m. –N-compounds, 19.1% f.m. –NFE) and ‘Lukasówka’ cv. (average 23.1% f.m. –dry matter., 0.5% f.m. –N-compounds, 19.2% f.m. –NEF). The highest fiber content was determinated in friuts ‘Faworytka’ (average peel – 7.2% f.m., flesh – 0.7% f.m..).Whereas the highest concentration of vitamin C was observed in the peel and flesh of ‘Concorde’ (8.0–7.8 mg 100^-1 f.m.), ‘Faworytka’ (7.6–7.4 mg 100^-1 f.m.) and ‘Lukasówka’ (8.4–8.0 mg 100^-1 f.m.). While considering a mineral compound concentration, the richest were ‘Concorde’ cultivar pears (peel – 0.4% f.m.; flesh – 0. % f.m.). Out of the studied pear cultivars the lowest concentration of these elements was established in the ‘Conference’ and ‘Komisówka’ cultivars. There was determined the highest content of K in fruits of ‘Bonkreta Williamsa’, ‘Concorde’, ‘Komisówka and ‘Konferencja, Na – ‘Faworytka’ and ‘Lukasówka, Ca – ‘Concord’ and ‘Konferencja’, Mg – ‘Komisówka’, Mn – ‘Bonkreta Williamsa’ and ‘Concorde’ and Fe – ‘Concorde’. In most investigated pears, there was noted a higher concentrations of nutrients in fruit produced in 2009 year compared to 2010.

Phoma strasseri is one of the major pathogen of peppermint (Mentha piperita). An important criterion in the classification of Phoma spp. is conidiogenesis, which has never been studied in P. strasseri before. The analysis using a FEI Tecnai Spirit G² electron microscope revealed enteroblastic phialidic ontogeny as a type of conidiogenesis present in this species. Conidia are formed on small conidiogenous cells, called phialides. The tip of the conidiogenous cell is surrounded by a characteristic collarette. The surface of the conidium wall is covered with a mucilaginous sheath, which may enable conidia to attach to the plant surface.

The improvement in zucchini growth in climatic conditions of Poland can be achieved by soil mulching and flat covering of plants. In the years 2009–2010, in Research – Horticulture Station belonging to Department of Horticulture at Wrocław University of Environmental and Life Sciences there was conducted two-factorial experiment with the use of synthetic mulches (polyethylene black and white foil, black polypropylene agrotextile), as well as flat covers (polypropylene agrotextile, perforated foil) in cultivation of Astra cultivar of zucchini. The experiment was established according to randomized split plot design, in three replications. Zucchini was planted on 12th May. There was not recorded any influence of mulches type on total and early yield of zucchini fruits. Additional application of flat covers made of PP agrotextile and perforated foil resulted in increase in total fruit yield in relation to control treatment by 26.7% and 44%, respectively and to the yield from plots which were only mulched – average by 47.3%. When using covers, early yield was average by 40.7% and by 47.9% higher. The highest total fruit yield (99.85 t ha^-1) was obtained in cultivation on PP agrotextile mulch with a perforated foil used as cover the plants. Fruits of 8–15 cm length accumulated the most considerable quantities of vitamin C, as well as phosphorus and potassium, while in fruits > 22 cm long there was recorded the highest amount of nitrates and carotenes.

Sooty blotch is one of the most common disease of apples in organic orchards in many countries. Results of molecular studies performed in USA indicated approximately 30 different fungi species associated with this disease. Fungi species causing sooty blotch in Northern, Central and Eastern Poland were identified on the basis of morphology and nucleotide sequence of the rDNA internal transcribed spacer region (ITS). A total 245 isolates were collected in spring and early summer in the years 2006–2009 from fruits with visible symptoms of the disease. Isolates were grown on PDA medium and identified on the basis of morphological characters. DNA was extracted from representative isolates and used as matrices for PCR amplification with ITS1F and ITS4 primers. Fragments of amplified rDNA ITS were sequenced. It was found that 66.53% of all isolates causing sooty blotch were species from genera Microcyclosporella, followed by Aureobasidium pullulans – 22.86%, Microcyclospora sp. –6.12%, Phialophora sessilis – 3.67%, Peltaster sp. and P. fructicola – 0.41%.

The problems in the cultivation of highbush blueberry and cranberry are diseases caused by infections factor, particularly by fungi and lately also by viruses. In the years 2008–2010 research concerning the detection and identification of viruses occurring on production plantations of the highbush blueberry located in the central and south-eastern Poland and the cranberry growing on the separate parts of the plantation in the central Poland using the serological ELISA test and PCR technique were performed. The results of the performed serological ELISA test showed the presence on the bushes of various cultivars of the Blueberry shoestring virus (BSSV) and Peach rosette mosaic virus (PRMV) (central and south-eastern Poland) and the Blueberry scorch virus (BlScV) and Tobacco ringspot virus (TRSV) (central Poland). During the observations carried out on the plantings of the highbush blueberry only the symptoms characteristic for the infection with the BlScV were noted (central Poland). This virus was also detected using DAS-ELISA test in the cranberry plants growing in the separate parts of plantations in the central region of Poland (Plantation A/W), which did not show any disease symptoms. In Europe it is the first report on the occurrence of BlScV in the cranberry bushes. What is more, it was established that the viruses can be detected in the leaves, the flowers and the phloem + periderm + cortex parenchyma samples in which the investigations could be performed in various months in the year. In the bushes of the blueberry of the Darrow and Herbert cultivars from Plantation A/W (central Poland) showing the symptoms in the form of red spots on the leaves or red spots and rings on the stems the presence of the Blueberry red ringspot virus (BRRSV) was confirmed using the PCR technique. In Poland it is the first report concerning the occurrence of the virus in the bushes of the highbush blueberry following those published in the Czech Republic and Slovakia.

Growing herbal plants is aimed at obtaining high yield of raw material with high contents of biologically active substances, as well as other important compounds, also of nutritional character. In the years 2008–2010 (February – May) studies were conducted on the relationship between cultivar, nitrogen dose (NH₄NO₃), potassium dose (K₂SO₄), and some components of chemical composition of basil herb. The study subject were basil plants of two Polish cultivars: Kasia and Wala, as well as the green-leaved form, popular on the domestic fresh herb market. Basil was grown in the greenhouse, in pots of the capacity of 4 dm³. Four doses of nitrogen and two doses potassium were applied. In the herb collected during full flowering dry matter, N-NH₄ and N-NO₃, nitrogen total, potassium and protein contents were determined. It was demonstrated that average dry matter contents in the herb of examined basil plants was 13.20% and significantly depended on the cultivar and dose of applied nitrogen. The most (15.47%) dry matter was found in the herb of Wala cultivar plants. The increasing nitrogen doses caused the increase of protein contents in basil herb. The most (26.13% d.m.) of protein was found in the herb of plants fed with the highest dose of nitrogen. Plants receiving the most potassium had more (23.24% d.m.) protein in the herb than plants receiving less of that nutrient (22.31% d.m.). Mean content of nitrate nitrogen in the examined herbal material was 0.78% d.m. Plants of Wala cultivar had significantly lower (0.66% d.m.) amount of nitrate nitrogen than the remaining ones. Additionally increased contents were demonstrated of nitrogen (total, ammonium, nitrate) and potassium in basil herb as an effect of increased nitrogen dose.

Intercropping of vegetables is experiencing a renaissance with the uptake of organic farming. Cultivation of several plant species simultaneously eliminates negative traits of homogenous cultivation, supports bio-diversity and remains compliant with the rule of balanced agriculture. Carrot and root parsley are two vegetables that have very high requirements towards the conditions of growth. Their cultivation together with other species is a conscious introduction of competitive plants, therefore it was interesting to observe their reaction to intercropping. Among various combinations of compared cultivation types, intercropping with onion turned out to be most beneficial to both carrot and parsley. The ones cultivated together with onion created the highest yield of marketable roots, total yield and yield of leaves. Onion growing next to them had positive effect on the structure of root yield, especially in case of carrot, increasing commercial root share. Intercropping of carrot and parsley with marigold had unfavorable effect on yielding and growth of these vegetables. Intercropping did not affect the number of carrot and parsley emergence, nor yield of fine roots. Total marketable yield of root vegetables obtained from intercropping with onion was greater than that from homogenous cultivation. The effect of intercropping of carrot with parsley was modified by a year of research.

Amaranth is not only of high dietetic (seeds and leaves), but also pro-health, ecological, agricultural, and ornamental quality. The aim of present research was to analyze the influence of cultivar, plant spacing, and diverse NPK fertilization on yielding and Cu, Zn, Fe, and Mn contents in seeds, leaves, and stems of amaranth (Amaranthus cruentus L.). The paper was based on three-year field experiment established by means of randomized sub-blocks (split-plot) in three replicates and included three variable factors: plant cultivar, spacing (two levels each), and NPK fertilization (four levels). Achieved results indicated that applied experimental factors contributed to a substantial differentiation of Amaranthus cruentus yields. Amaranth reacted with a significant increase of yields due to NPK fertilization. The highest yields were produced when fertilizing was applied at the rate of 90 kg N∙ha^-1, 60 kg P∙ha^-1 and 60 kg K∙ha^-1. Use of the highest NPK fertilization (130 kg N∙ha^-1, 70 kg P∙ha^-1, 70 kg K∙ha^-1) was associated with the decrease of the test plant yielding, regardless of the cultivar or plant spacing. In most cases, the experimental factors exerted significant influence on the contents of analyzed microelements in leaves and seeds of amaranth plants. Analysis of partial eta-squared coefficients indicated that the plant cultivar explained the amaranth’s yielding variability to the highest degree, while NPK fertilization – copper, zinc, and iron levels in leaves, and copper and manganese in seeds. Manganese in leaves and zinc in seeds was the best explained by the cultivar of the test plant.

The nutritive value of Beta vulgaris L. result mainly from its high content of protein gathered both in leaf blades and in petioles, and from high content of mineral salts, mainly iron and calcium, as well as vitamins C, A, B₁, B₂. Purpose of the research was to determine the effect of type potassium fertilizer (potassium chloride, potassium sulphate and potassium chloride + potassium sulphate in 1:1 K ratio) and different dose of potassium (0.6; 1.2; 1.8 g∙dm^-3) on the yield and chemical composition of Beta vulgaris L. The plants were cultivated in a greenhouse, in pots filled deacidified highmoor peat. Regardless of the type of potassium fertilizer, the yield of Beta leaves was the highest with the application of 0.6 g K·dm^-3. Leaves of Beta vulgaris L. fertilized with potassium chloride contained least nitrates, whereas plants fertilized with K₂SO₄ and KCl + K₂SO₄ contained much more nitrates. Increasing doses of potassium had a positive effect on the content of vitamin C in the leaves. The research revealed a negative effect of increasing potassium dose on the plant unit weight, leaf length and percentage content of total nitrogen, protein and dry weight in leaves, especially at application of potassium chloride and potassium sulphate. The research showed the growth of potassium and total salt concentration content in bedding as the effect of increasing potassium doses at the application of KCl and K₂SO₄. In cultivation of Beta vulgaris L., the application of 0.6 g K·dm^-3 bedding leads to the highest yield of leaf fresh weight, while application of 1.8 g K·dm^-3 bedding leads to the highest content of vitamin C in fresh mass.