Field cultivation of vegetables in Poland is strictly related to weather conditions. Low temperatures occurring from November to March limit vegetable cultivation in the field. However protecting plants with row covers can prevent losses from untimely frosts and freezes and provide a means to modify the environment around the plant, favorably resulting in more rapid growth, earlier maturity, and possibly increased yields. Experiments were carried out in 2008–2010 at the experimental field of the Agricultural University of Kraków (N 50º4’, W 19º50’) in order to determine the impact of flat covers made from biodegradable nonwovens produced by the Institute of Biopolymers and Chemical Fibres and CENARO in Łódź. Seeds of frost-resistant ‘Glacier’ cultivar of onion were sown in the end of August, and after a significant drop in temperature occurred in the second half of November plants was covered with biodegradable nonwovens such as: Bionolle 59 g m^-2 and 100 g m^-2 and IBWCH 50 g m^-2 and 75 g m^-2, as well as standard nonwoven polypropylene PP 50 g m^-2. A plot that remained uncovered throughout the winter served as the control. The covers were kept until spring and were removed one (2009) and two months (2010) before harvest. During harvest, measurements of plant height and marketable yield were taken. In the laboratory harvested onions were estimated for ascorbic acid, dry matter, soluble sugar and nitrates content. The investigations showed that covering onion with biodegradable nonwoven material had a positive impact on yield in the first year of the experiment. There were no significant differences in the yield quantity in the second year. Contents of the analysed organic compounds showed no regular patterns in both years of the experiment. In 2009, the vitamin C, dry matter and nitrate contents were higher than in 2010. In the second year of the study, the control onions had the most soluble sugars.

No-tillage cultivation using cover crops is an important part of sustainable horticulture, however there are only few date on this subject related to ‘Hamburg’ parsley. In two years` field experiment no-tillage cultivation using white mustard as a cover crop did not affect germination of ‘Hamburg’ parsley cv. Alba but further growth of no-tilled plants was slower. Yield of no-tilled plants with leaves was lower and the share of leaves in this yield was higher. Roots of no-tilled parsley were shorter and of lower weight, their yield was also lower but their health status was better. No-tillage did not have a negative effect on content of total nitrogen, phosphorus, potassium, calcium and magnesium in parsley leaves. No-tilled roots contained dry matter, total sugars and essential oils more and the content of L-ascorbic acid and of monosaccharides did not depend on cultivation method. No-tilled soil covered with mustard mulch was more moist, less porous and of higher bulk density. Mustard mulch controlled annual weeds in interrows well but it did not control weeds germinating in rows where parsley was seeded. Control of wintering and winter hard weeds was dependent on biomass produced by mustard plants.

Cichorium intybus is edible, medicinal and forage plant. The pharmaceutical raw materials were obtained from wild chicory (var. silvestre). Currently, farmers are increasingly assume plantations of wild chicory, and breeders are attempting to produce cultivars for medicinal purposes. In the modern breeding of chicory important feature is the ability to clonal propagation in vitro culture. The aim of our study was to assess capacity of natural population of wild chicory for plant regeneration from leaf explants. In the first was examined the effect of 16 combinations of various concentrations of IAA and 2iP on the regeneration of shoots from leaf explants (0.5 cm²). After that, 25 plants were propagated on the medium which was found as optimal. Then, their callus growth and shoots regeneration capacities were compared. Later on, was examined the effect of various IAA concentrations on the rooting of shoots. The majority of the shoots was regenerated from callus but direct organogenesis was also observed (8%). Shoot regeneration was found to be the most efficient on MS medium containing 0.5 mg dm^-3 IAA and 4 mg dm^-3 2iP – 97% of the explants produced shoots, while the average number of shoots was 15.5. The amount of callus was found to be a highly heritable trait (h² = 0.83). Lower the heritability coefficients were obtained for the number of shoots per explant (0.55) and the average shoot weight (0.40). The wild chicory shoots rooted easily. The number and weight of roots increased with the increasing concentration of IAA.

Recent years have been marked with a more common use of mineral fertilizers comprising marine algal extracts in horticultural production. Seaweed extracts are reported to possess, among others, biostimmulatory potential that improves yield growth and its quality as well as promotes plant resistance to adverse environmental agents. The marine alga processing technologies facilitate the extraction of active substances valuable for plant crops as stimulants for a number of plant physiological processes. The substances can be incorporated into both, soil or foliar applied fertilizers. The present research objective was to assess the influence of N Pro technology and Seactiv complex based on marine algal extracts on apple tree ‘Szampion’ growth, yield quantity and quality. The experimental material comprised ‘Szampion’ apple trees grafted on M.26 stock, the trees were aged 10 years at the experiment onset. The study aimed at evaluation of growth, yield quantity and quality of ‘Szampion’ apple trees fertilized according to two following programs. The measurements performed showed that introduction of the fertilization programs based on marine algal extracts had significant effect on total yield, one fruit weight, firmness and sugar extract content in apple tree ‘Szampion’ fruits. It was found that the N Pro technology and Seactiv complex had significantly beneficial influence on the percentage of big fruits, i.e. above 7.5 cm diameter and marketable yield in each experimental year. Cropping efficiency coefficient (CEC) of ‘Szampion’ apple trees fertilized according to N Pro technology and Seactiv base was significantly higher compared to control solely in 2008, in the other research years the differences were insignificant. The fertilization program based on marine algal extracts had positive influence on the ‘Szampion’ apple tree`s annual increments and each year the trees under N Pro and Seactive complex fertilization technology produced higher increments as against control; the differences in the last research year were significant. The N Pro technology and Seactiv base had positive impact on ‘Szampion’ apple tree leaf surface area, significant influence was observed in the second and third research year.

Up-to-date production of shallots for commercial purposes was limited due to low supply of the seeding material as well as no breeding cultivars that would produce seeds. Local populations commonly grown in various countries are reproduced mainly in vegetative way, because they usually do not produce generative shoots nor seeds, or they are formed, but in a very reduced number. The aim of this study, conducted in the period 2009–2012, was to evaluate generative growth and seed production in shallot grown from seedlings planted in summer at different dates, without producing mother bulbs. The study included 4 shallot cultivars – ‘Toto’, ‘Ambition F₁’, ‘Bonilla F₁’, and ‘Matador F_`1’. Seedlings (4 weeks old) were planted in the field on three dates – 3^rd decade of July, 1^st decade of August, and 3^rd decade of August. In the second year of cultivation, after the plants had overwintered in the ground, losses in plants, the percentage of plants producing seed stalks and some traits of these stalks as well as seed yield in the true breeding cultivar ‘Toto’ were determined. Plants of the other cultivars were not allowed to produce seeds (inflorescence umbels were topped before flower opening), since these were hybrids and undesired cross-breeding could occur. The study showed that overwintering losses in plants were on average 26.3%, but they were the lowest in cv. ‘Toto’, in particular among plants obtained from the first date of planting seedlings. Irrespective of the cultivar, the largest amount of plants with developed seed stalks and with their highest number per plant were recorded in the treatments where the first planting date was used. A delay in planting seedlings in the first year of cultivation by 2–4 weeks had a significant effect on reducing the percentage of plants developing seed stalks in the second year, while in cv. ‘Toto” it resulted in a very high decrease in seed yield.

Propagation conditions of bedding plants can eliminate or reduce the possibility of AMF inoculation of the root system during greenhouse production. Due to the ability of AMF to increase plant growth the effects of AMF and CO₂ enrichment on rooting and some physiological traits of geranium and osteospermum cuttings were investigated. AMF and CO₂ enrichment increased leaf number and fresh and dry weights of osteospermum shoots. Mycorrhization also significantly increased the length and fresh and dry weights of osteospermum roots formed in CO₂ enriched atmosphere but it did not affect root system developed in ambient atmosphere. AMF increased the length and fresh weight of geranium roots, irrespectively of CO₂ concentration, and dry weight of roots in CO₂ enriched atmosphere. Transpiration and stomatal conductance values were higher in inoculated osteospermum at higher CO₂ concentration. Mycorrhization and CO₂ enrichment increased photosynthetic activity of garden geranium leaves and this effect was connected with the increased ratio of variable to maximum chlorophyll fluorescence (F_v/F_m).

Phoma negriana is a little-known pathogen of grapevine canes but increasingly often it is listed in the countries of southern Europe and Asia. The work concerns a study of the opportunities for growth and development of the fungus at different temperatures, pathogenicity tests and the influence of biotechnical preparations on the growth and development of the fungus in vitro. Studies have shown that mycelial growth of P. negriana is possible at the temperature range from 5 to 32ºC with the thermal optimum from 20 to 24ºC. The optimal temperatures for the abundant sporulation was 20, 24 and 28ºC. The positive results of pathogenicity tests as well as re-isolation of the fungus from inoculated shoots confirmed the possibility of grapevine canes infection by P. negriana. A significant factor in facilitating infection were injuries of shoots, what indicates that the fungus is a facultative pathogen of grapevine. Biosept Active limited the growth and development of P. negriana significantly more strongly than Beta-Chikol. When it was applied at the concentration of 0.3%, it caused destruction and loss of fungal hyphae vitality.

The use of high quality sowing material is the fundamental condition for good yielding of crop plants. One of new, unconventional methods of seed quality improvement is low-frequency variable magnetic field. It has been found that this physical factor has a favourable effect on seed germination, emergence and growth of many crop plants. The objective of the study was to determine the effect of low-frequency magnetic field (LFMF) on the germination of radish seeds, with particular emphasis on old seeds. The experimental material were seeds of 7 lots of radish cv. ‘Mila’, with germination capacity of 66.5–92.5%. The age of the seeds was from 1 to 8 years. Seeds from all the lots were treated with variable magnetic field with frequency of 50 Hz, at 3 doses of magnetic induction as follows: 0 (control), 30 and 60 mT for 30 seconds. Then, the seed germination energy and capacity were determined, as well as the length of the hypocotyl and of the radicle of the seedling, dry weight of seedling, and emergence and mean time of emergence. The low frequency magnetic field exposure (30 and 60 mT) improved radish seed germination energy and capacity of every old seed lot. The increase of germination energy of old seeds amounted to 12.3–19.2%, and the increase of germination capacity was 5.8–10%. Magnetic field stimulation caused the increase of germination energy for 3 out of 4 seed lots of high quality but did not affect the improvement of germination capacity of those lots. No significant effect of magnetic field of seeds on the hypocotyl and radicle elongation was observed with the exception of 1 out of the 7 seed lots. For the 2 old seed lots out of the 3 total, magnetic field treatment caused the increase of emergence by 4.4–13.0%.

Self-incompatibility is common in apricot (Prunus armeniaca L.) cultivars of Central Asian and Irano-Caucasian ecogeographical groups, while cultivars of European group are traditionally considered as self-compatible. However, the number of known self-incompatible cultivars of the European group has increased rapidly over the last two decades. This can be explained by using Asian or North American self-incompatible cultivars in breeding programs that aim to create new genotypes with the traits including: Plum Pox Virus resistance, frost tolerance, increase of the sugar content or extending the harvest time. In this work self-(in)compatibility was tested in 38 apricot cultivars. Pollen-tube growth in pistils pollinated in laboratory was analysed using fluorescence microscopy. Cultivars were considered self-compatible if at least one pollen tube reached the ovary in the majority of pistils. In self-incompatible cultivars growth of pollen tubes in the style of pistil stopped along with formation of characteristic swellings. Of the examined cultivars, 17 were self-compatible, and 21 were self-incompatible.

The response of berry organic acids of four organically grown table grape cultivars to cane-girdling and cluster-berry thinning treatments were evaluated over two growing seasons. In addition pH, titratable acidity, soluble solids content and maturity index were also determined. Statistical analyses showed that individual organic acid content of the four grape cultivars were significantly affected by the treatments. Tartaric and malic acids of ‘Red Globe’ were mostly influenced by the cluster-berry thinning treatment. ‘Alphonse Lavalleé’ accumulated the highest tartaric acid and malic acid in both the girdled/thinned and the cluster-berry thinned vines, respectively. The control and girdled ‘Trakya Ilkeren’ vines had the most tartaric acid. Control vines also contained high malic acid amount. ‘Buca Razakısı’, on the other hand, had the most prominent tartaric and malic acid levels in the girdled/thinned and thinned vines, respectively. Quality parameters also showed significant differences among the cultivars in response to the treatments.

Different aspects of living mulches application in vegetable crops production is discussed in the paper. They compete with vegetables for light, moisture and nutrients and for this reason in most cases cause the yield reduction of cash crops. However, at the end of vegetation period, after ploughing down as green manure they enhance the organic matter content in the soil, improve its physical and chemical properties, which are beneficial for the subsequent species in crop rotation. Undersowing is best suited in perennial crops like rhubarb or the species with relatively long vegetation period, grown from transplants (leek, cabbage, sweet corn, stake tomato, pepper). The most important attributes required for species used as living mulches are quick emergence and soil covering, short height, low water and nutrients demands. In most cases the legume crops (white clover Trifolium repens L., red clover Trifolium pratense L., hairy vetch Vicia villosa Roth., seradella Ornithopus sativus Brot.), grasses (perennial ryegrass Lolium perenne L.) or cereals, especially rye Secale cereale L. are used for this purpose. Their competitiveness to the cash crops may be diminished by the delayed term of undersowing the only in strips between plant rows, mowing the biomass or the use of sublethal doses of herbicides. The beneficial effects of living mulches include the suppression of weed infestation, reduced insect pests and diseases pressure, and prevention from soil degradation. They suppress soil compaction, wind and water erosion, improve soil structure, reduce the surface water runoff and nutrients leaching. Living mulch cover is favourable for biological activity of the soil and the amounts of available nutrients after decomposition. Further intensive studies will be needed to introduce such intercropping, friendly to the environment system to the wide practice, especially in the terms of possible decrease of competitiveness to the cash crops.

The concentration of non-enzymatic antioxidants such as ascorbate and glutathione in tissues is one of the major plant responses to biotic and many abiotic stresses, including metals. Therefore, it is crucial to develop the most effective methods for simultaneous quantitative analysis of these antioxidants. Capillary zone electrophoresis allows relatively fast and effective analysis. The aim of the paper was to apply and optimise the capillary electrophoresis conditions for simultaneous determination of glutathione, glutathione disulphide, ascorbate, and dehydroascorbate in small plant tissue samples exposed to copper and cadmium. The method ensures good linearity and reproducibility, with correlation coefficients 0.988 for ascorbate and 0.999 for glutathione and glutathione disulphide, and with detection limits approximately 2.50, 0.65 and 0.50 ppm, respectively. Cu stress was found to increase the ascorbate concentration and glutathione content in leaves, while Cd increased glutathione in the oldest leaf segments and root.

One of the requirements for early and profitable fruit cropping is the quality of trees used for orchard establishment. Nursery tree quality is influenced by many factors, among which the method of tree propagation plays an important role. In these experiments, the knip-boom (KB) trees produced in the 3-year cycle, from either sleeping buds (B) or bench-grafts (G), were compared in terms of tree quality parameters. B-trees outperformed G-trees in trunk diameter, total shoot extension, and in the number of shoots > 10 cm. No significant differences were found in such features as tree height, apical dominance and the percent of the number of shoots suitable for tree training. Studies on spatial configuration of lateral shoots and their length did not show any essential differences in the shape of canopy between both tree types. However, lateral shoots of B-trees were significantly longer than those of G-trees. Linear correlations between different quality characteristics in both types of trees demonstrated greater strength of either positive or negative correlations in G-compared with B-trees. We have not found any essential differences between B- and G-trees in nursery tree performance; therefore for a full evaluation of the trees produced by either method of propagation should be based on the analysis of nursery production economics and orchard performance of the trees (B and G) used.

The aim of the research was to find out how foliar selenium (Se) treatment in open field conditions affects plant nutrition, yield and bulb bioactive properties. 10, 50 or 100 µg·mL^-1 Se, referred to as Se10, Se50 and Se100 treatments, was applied to onion ‘Hercules’ in 2008 and 2009. Bulb weight, total yield, content of total Se, free selenomethionine and selenomethylselenocysteine, total S, N, P, K, Ca and Mg, content of total phenolics, pungency and total antioxidant capacity (TAC) were determined. All Se treatments significantly reduced bulb S content. The Se100 treatment had a tendency to decrease bulb size and yield. The Se50 treatment increased total Se content, total phenolics and TAC and had a tendency to increase the yield. A larger proportion of total Se was converted into organic compounds in the Se50 than in the Se100 treatment. In Se 10 treatment, bulb TAC was the highest among treatments in 2009. Considering both agronomic and human health benefits, Na₂SeO₄ solution at the rate of 50 μg·mL^-1 Se can be recommended for bulb onion.

The pharmacological and culinary usefulness of hot pepper fruits is determined, among others, by the content of capsaicinoids that give hot peppers a pungent burning taste. The content of these compounds in hot pepper is primarily determined by the genetic traits of a cultivar and is modified by various factors: weather conditions during the growing season, fertilization, harvest time, and fruit maturity stage. The aim of the present study was to evaluate the effect of fruit maturity stage: green fruits, fruits turning colour as well as physiologically mature fruits (red), and fruit harvest date: the first and third decade of September, on the content of capsaicinoids in four hot pepper cultivars: ‘Cyklon’, ‘Orkan’, ‘Rokita’, and ‘Bronowicka Ostra’. In this study, which was carried out in 2005 and 2006, the content of capsaicinoids (capsaicin and dihydrocapsaicin) was measured by HPLC. The highest amount of capsaicinoids was obtained in the fruits of hot pepper that were harvested at the initial stage of maturity – in green fruits (on average 309 mg∙kg^-1), compared to fruits turning red (258) and red fruits (250 mg∙kg^-1). Peppers selected in the third decade of September contained more capsaicinoids (on average 301 mg∙kg^-1) than those harvested in the first decade of this month (243 mg∙kg^-1). Fruits of the evaluated cultivars differed in capsaicinoids content; on average it ranged from 212 (‘Cyklon’) to 326 mg∙kg^-1 (‘Bronowicka Ostra’). In fruits of all the quantitative ratio of capsaicin to dihydrocapsaicin was at a similar level, ranging between 11.9 and 12.9. The capsaicinoids content in fruits of the investigated cultivars differed between years 2005 (302) and 2006 (243 mg∙kg^-1).

Allium aflatunense and Allium karataviense are valuable bulbous plants grown in a garden. Moreover, Allium aflatunense is one of the most decorative species for cut flowers industry. These plants characterize with a low multiplication rate. Immature inflorescence stem sections and leaf bases isolated from ‘Allium aflatunense ‘Purple Sensation’ and Allium karataviense ‘Ivory Queen’ bulbs in October were used as source of explants for shoot regeneration. The use of a two – step sterilization procedure (2% Cl^- – 30 min and 1% Cl^- –15 min) gave much better results than a one – step (2% Cl^- – 30 min). Inflorescence explants in inverted orientation were cultured on a Murashige and Skoog [1962] medium containing BA in concentration of 2 mg·dm^-3 and NAA in concentration of 1 mg·dm^-3. Leaf bases placed in normal and inverted orientation were incubated on MS medium supplemented with: BA 2 mg·dm^-3 plus NAA 1 mg·dm^-3, BA 5 mg·dm^-3 plus NAA 1 mg·dm^-3 and TDZ 1 mg·dm^-3 plus NAA 1 mg·dm^-3. In subsequent experiments clumps consisting of 2 shoots were cultured on MS medium containing BA 0.5, 1, 2 mg·dm^-3 with NAA 0.1 mg·dm^-3 and BA 2 mg·dm^-3 with IAA 0.1 mg·dm^-3 for 6 weeks. A multiplication rate during four subcultures on medium with addition of BA 0.5 mg·dm^-3 and NAA 0.1 mg·dm^-3 was also examined. Explants from young inflorescences and from immature leaf bases were found effective to form shoots. The orientation of leaf explants did not have a significant effect on the number of regenerating shoots. 5.7 to 7.5 shoots were achieved for Allium aflatunense ‘Purple Sensation’ on studied media during 6 weeks of multiplication and 3.5 to 5.1 shoots for Allium karataviense ‘Ivory Queen’. Multiplication rate of 31.3 shoots for Allium aflatunense ‘Purple Sensation’ and 26.6 shoots for Allium karataviense ‘Ivory Queen’ was possible to obtain on medium supplemented with BA 0.5 mg·dm^-3 and NAA 0.1 mg·dm^-3 after 32 weeks of culture.

Scorzonera hispanica is a rich source of inulin – a glycoside which has a positive effect on human and animal organisms. The paper presents studies on fungi threatening the cultivation of scorzonera. Soil mulching with intercrop cover crops such as oats, tansy phacelia and spring vetch had a positive effect on the population and healthiness of the seedlings and the roots of the studied plant. The following fungi were most frequently isolated from the infected underground organs of scorzonera: Alternaria alternata, A. scorzonerae, Botrytis cinerea, Cylindrocarpon didymum, Fusarium culmorum, F. oxysporum, F. solani, Rhizoctonia solani, Phytophthora sp. and Sclerotinia sclerotiorum. Among the applied mulching plants, oats proved to be the most effective in inhibiting the occurrence of the enumerated fungi species.

Leaf celery (Apium graveolens L. var. secalinum Alef.) is a vegetable with spicy and medicinal properties. A study on the effect of seeding rate and irrigation on yield of two leaf celery cultivars: ‘Gewone Snij’ and ‘Green Cuttnig’, was carried out at the Felin Experimental Farm of the University of Life Sciences in Lublin during the period 2009–2010. Seeds were sown in the field in the last decade of April in rows 25 cm apart. Two seeding rates were used: 15 and 25 kg·ha-1. Plant irrigation was applied during critical periods of soil water deficit. The raw material was harvested twice: in the 2nd decade of August and in the 2nd decade of October. The investigated factors were shown to have a significant effect on leaf celery yield. A significantly higher content of essential oil was found in the leaves of both celery cultivars harvested on the first date. The highest essential oil yield was obtained from irrigated plants of the cultivar ‘Green Cutting’ harvested in the 2nd decade of August. The main components of the essential oil of leaf celery were limonene and myrcene.