The aim of study was to estimate the effectiveness of polypropylene woven (PP-17) covers usage in growing of stem lettuce. The seeds of ‘Karola’ cultivar were sown in non-heated green-house in the middle of March. The seedlings were planted in the last ten days of April at spacing 40 × 30 cm . The plants were grown in the soil mulched with black cover propylene non-woven. Some plants were covered with a transparent propylene non-woven, others remained not covered (control group). A significant effect of polypropylene non-woven usage was found regarding quantity and quality of stem lettuce. The harvest was forced by 4 days earlier (on average) and the increase of marketable yield of stems was 20.9% in comparison with open-field production. The plants grown under covers showed higher unit weight and the diameters of edible stems as well as higher dry weight content and total sugar content including reducing sugar. The mulching of soil with black propylene non-woven did not affect considerably productivity and yield quality of stem lettuce compared to control group (open-field).

The experiment was carried out in the years 2006–2008. The aim of the study was estimation of yielding of Italian cultivar of endive ‘Blonda a cuor pleno’ (escarole group) grown in the conditions of Western Pomerania. Seeds of endive were sown on four dates: 10, 20 and 30 June, and 10 July. There were two plant spacing used in the experiment: 40 × 25 and 40 × 35 cm. Significantly the highest yield of leaf rosettes was obtained when seeds were sown on 30 June. However, sowing seeds on 10 June had an effect on obtaining rosettes of the highest weight. This planting date had also an influence on decrease of marketable yield because of premature floral stalks development in long-day conditions. Significantly higher yield of rosettes of the highest weight and diameter was obtained from planting transplants at the spacing of 40 × 25 cm.

In two field experiments carried out in 2006–2008, with two radish cultivars Treto F₁ and Wernar F₁ the effect of differentiated nitrogen fertilization on yield and biological value of radish grown for autumn harvest was examined. Mineral N content in the soil before seeds sowing was raised up to the level of: 50, 100 and 150 mg N·dm^-3 by using: ammonium nitrate 34% N – [NH₄NO₃], calcium nitrate 15.5% N – [Ca(NO₃)₂·H₂O], ammonium sulphate 20.0% N – [(NH4)₂SO₄], and ENTEC 26% N – [NH₄NO₃+(NH₄)₂SO₄ + 0.8% DNPP]. The highest marketable yield of radish Treto F₁ cv. was achieved in the case of ammonium nitrate use. In the case of Wernar F₁ cv. kind of fertilizer didn’t affect the yield. Irrespective of the kind of fertilizer, increment of nitrogen content in the soil from 50 to 100 mg N·dm^-3 caused the significant enhancement of radish yield. The similar yielding was recorded at nitrogen concentration equal to 150 mg N·dm^-3 and 100 mg N·dm^-3. Increasing mineral nitrogen concentration in the soil resulted in increment of nitrates content in radish roots, however their amounts not exceed permissible level. Plants fertilized with ammonium sulphate and ENTEC 26 contained lower amount of nitrates in edible parts in comparison to those supplied with ammonium nitrate and calcium nitrate.

The studies were carried out in the years 2006–2007 in an unheated glasshouse. Strawberry mother plants cv. ‘Elsanta’ were grown in polypropylene bags filled with peat-based substrate (3 plants per bag). The bags with plants were placed on gutters in the glasshouse at the height of 165 cm. The distance between the gutters was 120 cm. The experiment was established in a split-block design in 4 replications of 3 plants each. The aim of this work was to evaluate the influence of biostimulant based on animal protein hydrolysate on number, length and diameter of runners and number of strawberry daughter plants as well as their crown diameter, fresh weight and number of leaves. The application of biostimulant did not have a beneficial influence on number of runners, their length and diameter. Applied biostimulant did not also affect quantity of strawberry daughter plants, their crown diameter as well as number of leaves. Significant decreased in weight of daughter plants after biostimulant application was found. The quantity and quality of runners as well as daughter plants in compared years of the experiment were significantly different. These differences were probably caused by powdery mildew.

Carotene and ascorbic acid are the most important compounds for human nutrition that are supplied by vegetables. The content of carotene and ascorbic acid in vegetables depends on the species and the cultivar, but it is subject to changes under the influence of environmental conditions and agricultural factors. This study examined the effects of the sowing date (5, 15 and 25 May) on the content of carotenoids and L­ascorbic acid in the fruits of two cultivars of spaghetti squash (‘Makaronowa Warszawska’ and ‘Pyza’). Fruits were harvested in the fully mature, from the beginning of September till the beginning of October. The content of total carotenoid compounds in fruit was higher for the sowing date on 5 May than for the sowing dates on 15 and 25 May, while the content of β­ carotene did not significantly differ. The sowing date did not affect the content of L­ascorbic acid in fruits. Fruits of the ‘Makaronowa Warszawska’ contained more total carotenoids and β­ carotene than fruits of the ‘Pyza’, while the content of L­ascorbic acid in fruits of both cultivars did not significantly differ. Lower air temperatures and higher amounts of precipitation in the spaghetti squash vegetation period resulted in an increase in the β­ carotene content.

Intensification in plant growing is a direct reason for deteriorating soil properties, as well as conditions of plant growth and development. Aiming at improvement of soil fertility and structure, conservation tillage, limiting the processes of soil environment degradation, is introduced into garden crop production techniques. Field experiments were conducted in the years 2006–2008, on grey brown podzolic soil of impermanent structure. The experimental plant was scorzonera (Scorzonera hispanica L.) of ‘Duplex’ cultivar. Three intercrop plants were considered in the studies: common vetch (Vicia sativa L.), phacelia (Phacelia tanacetifolia B.) and oats (Avena sativa L.). There were also two ways of pre-sowing soil tillage: a) complex of pre-sowing practices, sowing of intercrop plant (2^nd decade of August), pre-winter ploughing and putting green matter into soil, b) complex of pre-sowing practices, sowing of intercrop plant (2^nd decade of August), spring ploughing and putting plant matter into soil, as well as two plant growing methods: on ridges and on flat soil. Significantly advantageous effects of spring putting intercrops into soil, growing of scorzonera on ridges and ploughing the soil with oats upon the total root yield were demonstrated. The examined experiment factors, however, did not significantly affect inulin, protein and dry matter contents in scorzonera roots. The most favorable tillage combination, as to inulin productivity was growing of scorzonera on ridges after spring ploughing oats with soil.

The most popular and efficient growing medium in soilless crop are rockwool but researches try to introduce as well other growing media to horticultural practice. Nowadays cherry tomato is a widespread typ grown under greenhouse conditions and grafting can be a resource let to obtain cultivars with a higher fruit yielding. Two tomato cultivars: typical cherry ones as ‘Dasher’ with red skin and ‘Organza‘ with yellow skin were grown in the years 2008–2009. Half of the plants were grafted on the stock of ‘Maxifort.‘Tomatoes were cultivated on organic media such as coconut fiber slabs, wood fiber slabs and rockwool slabs. Grafting increased yielding of cherry tomato in particular cultivated on coconut fiber and wood fiber slabs. The grafting plants of ‘Dasher’ cultivar produced much more fruit than not grafted ones. The increase of fruit weight as a result of grafting was observed in ‘Organza’ cultivar. Grafted plants of ‘Organza’ had significantly less fruit with BER than not grafted ones. ‘Dasher’ yielded considerably less than ‘Organza’. ‘Dasher’ produced the highest yield at the begining of harvest time. The yielding of ‘Organza’ was at the same level during the entire harvest time. Early yield of both cultivars was the highest on the wood fibre slabs with grafted plants. The growing media used in the experiment – coconut fiber and wood fiber, proved their suitability in tomato soilless cultivation.

The material for the study consisted of F₁ hybrid populations derived from crosses among strawberry genotypes such as: ‘Calypso’, ‘Evita’, ‘Ostara’, ‘Selva’ and ‘Senga Sengana’. The crosses were conducted in a complete diallel design in accordance with Griffing’s first method. In the analysed model, 8 quantitative characters such as: time of flowering and ripening, number of inflorescences, flowers per inflorescence, crowns and fruits as well as yield and average fruit weight were assessed. The obtained results showed that for the majority of analysed traits a considerable role is played by non-additive genetic effects except for ripening time, for which additive genetic effects were essential. Heritability coefficients of broad sense were very high in almost all cases, whereas ones of narrow sense were low for most characters. Yield was positively correlated with number of fruits, inflorescences and crowns.

The aim of the research was to assess genetic control, heritability and correlation of some quantitative characters on the basis of hierarchic crossing scheme. In the experiment two systems of classification were applied. In the first one superior classification was made according male forms (5♂ ×4♀) and in the second one female forms were superior (10♀ ×3♂). Genetic control for most analysed traits was the same regardless of classification system. Only in case of yield genetic control was different in paternal than in maternal classification. Additive genetic components were essential in determining the time of flowering, whereas non-additive ones in determining the number of stolons. The high value of broad-sense heritability for most cases suggests large genetic influence on analysed characteristics.

The experiment was established in the spring 1999 on lessive soil developed from light boulder clay. Apple trees of Golden Delicious cv. on M.26 rootstock were planted in 3.5 × 1.2 m (2381 trees·ha^-1) spacing. Research involved the effect of diversified levels of potassium fertilization: 12, 16 and 20 mg K 100 g^-1 d.m. of soil and three types of potassium fertilizers: potassium chloride (KCl), potassium sulfate (K₂SO₄) and potassium nitrate (KNO₃) on trees yielding and nutrition, as well as nutrient contents in the soil. Potassium fertilization using potassium chloride, potassium sulfate and potassium nitrate resulted in increased content of available potassium both in arable (0–20 cm) and in subarable (20–40 cm) layers of an apple orchard. Increase of available potassium content from 12 to 20 mg K∙100 g^-1 f. m of soil, due to fertilization with potassium chloride, potassium sulfate and potassium nitrate did increase soil pH (in H₂O) in arable and subarable layers as a result of higher contents of available calcium. Alkalizing effect of potassium sulfate and potassium nitrate, generally assumed as physiologically acidifying, occurred on neutral and alkaline soils [pH (in H₂O) over 6.90]. Fertilization with potassium chloride, potassium sulfate and potassium nitrate increased the content of sulfates in arable and subarable layers. The same result was observed in the case of chlorides in subarable layer. Application of potassium fertilization with potassium nitrate brought about decreased values of available magnesium content only in subarable layer. Due to the use of high rates of potassium nitrate, on the level 20 mg K·100 g^-1 of soil, there was observed increased soil salinity (EC) both in arable and subarable layers. Introduction of potassium fertilization and increasingly higher rates of potassium fertilizers did not influence on the content of nitrogen, phosphorus, potassium, calcium, magnesium, sulfur and chlorine in apple tree leaves. Increasing potassium levels in the soil and potassium fertilizers did not affect the yield of Golden Delicious apple trees after coming them into full fruition period.

Growing strawberries under covers in substrates allows to eliminate the application of soil decontamination, which is costly and harmful for the environment. At the same time it guarantees obtaining a higher and better quality yield, as compared to the traditional ground cultivations. In the years 2005–2006 studies were conducted, aiming at determining the effect of three kinds of substratum (peat, peat mixed with composted pine bark in the proportion of 1:1, peat mixed with composted pine sawdust in the proportion of 1:1) and differentiated nitrogen dose (140 or 210 mg N·dm^-3) upon yielding, chemical composition of leaves and fruit of strawberry (Fragaria × ananasa Duch.) of 'Honeoye' cultivar, grown in an unheated foil tunnel. The total and marketable yield quantity of strawberry fruit grown in peat and in peat with pine bark did not differ significantly. Lower total (407,1 g·plant^-1) and marketable fruit yield (264,6 g·plant^-1) was reported when plants were grown in peat mixed with sawdust. Plants grown in peat mixed with sawdust gave fruit with significantly lower unit weight compared to plants growing in the remaining substrates. The studies did not demonstrate a significant effect of differentiated nitrogen fertilization upon strawberry yielding. In the leaves of plants fertilized with nitrogen dose of 200 mg N·dm^-3 significantly more nitrogen was found, as well as less calcium, compared to plants fertilized with a smaller dose of this component. In the fruits of strawberry fertilized with a larger nitrogen dose, significantly more nitrates (V), total nitrogen and potassium were reported and less dry matter, extract and calcium compared to fruit collected from plants fertilized with nitrogen dose of 140 mg N·dm^-3.

The objective of studies carried out in years 2002–2009 was to determine the effect of nitrogen fertilization on the content of mineral components in the leaves of cherry trees and on the changes in assimilable components in the arable and subarable soil layers. Cherry orchards were established in spring 1999, 2001 and 2002 with the application of ‘Łutówka’ cultivar, type IR2. In the orchards planted in 2001 and 2002, trees were spaced in 4 × 1.3 m density (1920 trees ∙ ha^-1). In the orchard planted in 1999, the tree density was 4 × 2 m (1250 trees ∙ ha^-1). Orchards were planted on the same field, on grey-brown podzolic soil created on boulder clay sandy loam. In spring 2002, in each of the planted orchards, nitrogen fertilization was applied in the doses of 0, 50 and 120 kg ∙ ha^-1. Our studies have shown that the fertilization with the differentiated nitrogen doses carried out for many years exerted an effect on changes in the soil chemical properties, in comparison with the initial soil status in the year 2002. Contents of assimilable phosphorus and potassium, both in the arable and the subarable magnesium decreased in a lesser degree, while in the orchard planted in 2002, magnesium showed even an increase. However, it must be stressed that in spite of the lapse of time, the soil contents of phosphorus and magnesium, in comparison with the critical values, were on a high level, while potassium showed an optimal or high level, with pH value from 5.7 to 6.6. General analysis revealed that nitrogen fertilization, as well as the age trees exerted an influence on the content of components indicating that N fertilization exerted an increasing effect on nitrogen and magnesium contents, but it decreased the contents of potassium and calcium.

Abstracts. Studies were carried out in an experimental orchard in the years 2008–2009. Apple-trees of ‘Topaz’ cultivar were planted in five “soil localities”: 1 – directly in grubbed up rows of an apple-tree orchard, 2 – in herbicide fallow belts of grubbed up apple-tree orchard, 3 – in turf belts of grabbed up apple-tree orchard, 4 – in a locality after a four-year break in apple-tree cultivation, without any preparatory treatments and 5 – in a soil after previous agricultural use – virgin soil. During the studies realization, an evaluation of the soil biochemical properties was carried out. This evaluation was done on the basis of activity of enzymes: dehydrogenases, proteases, acid phosphatase and urease, IAA content, total content of organic carbon and of organic carbon soluble in water. Our studies have shown a significant influence of the soil locality and of the term of soil sampling for the identification of the biochemical properties of soil expressed by the enzymatic activity. The activity of three studied enzymes was significantly lower in the locality 1 in comparison with the soil in a locality 5. Also in case of indole-3-acetic acid (IAA), its highest value was found in the soil of combination 1 while the highest value of the IAA acid was found in combination 3. The previous method of soil utilization also exerted a significant influence on the content of organic matter in the soil. The content of total organic carbon and organic carbon soluble in water were significantly lower in the soil from the orchard planted directly after previous agricultural use. Enzymatic activity and content of organic carbon were the highest in the autumn period, while the lowest value was shown in summer.

Abstracts: Studies were carried out in the years 2008–2009 in the Experimental Orchard of Fruit Growing Department, on the area of RSGD in Przybroda. Apple-trees of ‘Topaz’ cultivar on M.26 rootstock were planted in five soil localities: 1 – directly in grubbed up rows of an apple-tree orchard, 2 – in herbicide fallow belts of grubbed up apple-tree orchard, 3 – in turf belts of grabbed up apple-tree orchard, 4 – in a locality after a four-year break in apple-tree cultivation, without any preparatory treatments and 5 – in a soil after previous agricultural use – virgin soil. During the realization of studies, the mineral soil content (P, K, Mg) was identified, the total content of nitrogen and the pH value of soil were determined. In order to recognize the nutritional status of trees, the mineral contents of leaves (N, P, K, Mg and Ca) were investigated. Obtained results indicated that the content of mineral components in the soil depended on the earlier applied cultivation methods and on the soil layer from which the samples were taken. The highest mineral content was found in the soil which had been earlier use for agricultural purposes. The content of total nitrogen in the soil was significantly differentiated, depending on the soil locality where the apple-trees were planted and on the term of sampling. In summer season, the total nitrogen content in the soil was on the lowest level. Soil locality and the content of mineral components in the soil exerted an influence on the mineral composition in the leaves of ‘Topaz’ cultivar apple-trees.

Tracheary elements appear already in the early stages of in vitro organogenesis and precede the formation of meristemoids and shoot primordia which further develop into shoots. Thus this process can be considered as an important indicator of potential, organogenic capability of the explants. The aim of this study was to investigate the effect of auxin (IAA), cytokinin (BAP), sucrose and the light conditions (light with 16-h photoperiod, darkness) upon de novo differentiation of tracheary elements (TEs) in callus derived from mature embryos of pepper cv. Bryza. Moreover, it was to determine the proliferation ability of the callus cells and changes of callus morphology. TEs were differentiated in the form of single cells, irregular clusters, strands and whirls exclusively with reticulate and pitted thickening of the secondary wall and the clusters occurred the most frequently. Cytokinin used alone, as well as in auxin combination, stimulated xylogenesis with the highest efficiency as well as with regard to the frequency and TE cell number within clusters. The highest number of TEs per cluster was obtained in the case of combination 0.1 mg·dm^-3 IAA + 0.1 mg·dm^-3 BAP on the light. Smooth surface, large cohesion cell degree and green colour are the morphological callus features accompanied by the effective TE formation.

In modern horticultural production attention is paid to creating the best conditions for growth and development of plants in order to increase crop yielding. Such task is to be met by, among others, modern organic-mineral fertilizers. In the experiment the effect of Aminoplant, Goëmar BM 86 and Goëmar Goteo on the growth, development, crop yield and quality of some herbs from Lamiaceae family was estimated. The applied preparations did not significantly affect the height of plants and the number of shoots in tested plants (sweet basil and marjoram) except of peppermint. The content of essential oil in herb of marjoram and peppermint was lower in plants watered with the investigated fertilizers then in the control and in sweet basil it was clearly lower only in the herb of plants watered with the preparation Goëmar Goteo as compared with herb harvested from the control plots and plots watered with Aminoplant and Goëmar BM 86. The biggest amount of total polyphenoles was noted in the herb of sweet basil harvested from plots watered with Goëmar BM 86 preparation, the least from plots watered with Goëmar Goteo. The highest mean content of flavonoid compounds in the green parts of peppermint was characteristic for plants from the control plots.

The cucumber crop size depends not only on the cultivar and agrotechnical conditions but also on proper pollination of flowers. The aim of the work was the investigation of the efficiency of bumblebees used in the cultivation of cucumber on the yield, physical parameters and chemical traits of fruits. The investigations were performed on two cucumber cultivars Pavlina F₁ and Natasia F₁ obtained from Seminis company. It was established as a three factor experiment in four replications. The bumblebees from the Koppert company was introduced to the cucumber cultivation two times. Marketable yield, the numbers of flowers and fruits as well as physical and chemical traits were investigated. Marketable yield of fruits from the treatment with bumblebees was at the similar level with marketable yield from the control treatment with significantly higher number of fruits in the bumblebees treatment. The yield of fruits of the first class was at the similar level in both treatments with significantly higher number of fruits in the control treatment. A higher firmness and better quality were characteristic for fruits in the treatments with bumblebees than from the control treatment. A higher nitrate content was characteristic for fruits from the control treatment and fruits from the second and third term of planting. A higher phosphorus content was noted in fruits from the treatment with bumblebees in the first and third term of cultivation and in fruits of the Pavlina F₁ cultivar.

Hot pepper fruits contain the chemical group of alkaloid compounds called capsaicinoids, which are responsible for the pungency of the Capsicum species. The aim of our study was to determine the chemical composition as well as the content of capsaicinoids in pepper fruits (Capsicum annuum L.) cultivars ‘Adorno’ and ‘Etna’, which were grown in the north-western Poland in 2009. Capsaicinoids were extracted from dry pepper fruits by solvents (acetone and hexane) and analyzed by GC/MS. The analysis revealed that the major components of the extracts are capsaicin, dihydrocapsaicin and nonivamide (pelargonic acid vanillylamide).

In 1999–2001 years two Rosa × hybrida cultivars, ‘Casanova’ and ‘Korlingo’, were obtained by bud-grafting on a thornless multiflora rootstock (Rosa multiflora Thunb.). The first factor studied was the rootstock quality: class I (base diameter Ø= 4–6 mm); class II (Ø= 3–4 mm); class III (Ø= 2–3 mm). The second factor studied was the scion size: thick scions (Ø= 6–8 mm); medium scions (Ø= 4–6 mm); thin scions (Ø= 2–4 mm). Plant mass of Rosa × hybrida shrubs was greater with class I than with class II or class III rootstocks. The shrubs obtained by bud-grafting on class I and class II rootstocks were higher than with III class rootstocks. Rose shrubs of greater height and mass were obtained by bud-grafting with medium scions, and shrubs of lowest height and mass were obtained with thin scions. The number of primary shoots was not significantly affected by either rootstock quality or scion size. Plant mass and plant height were greater in ‘Casanova’ than in ‘Korlingo’.

In 1999–2001 years two Rosa × hybrida cultivars, ‘Casanova’ and ‘Korlingo’, were obtained by bud-grafting on a thornless multiflora rootstock (Rosa multiflora Thunb.). The first factor studied was the rootstock quality: class I (base diameter Ø= 4–6 mm); class II (base diameter Ø= 3–4 mm); class III (base diameter Ø= 2–3 mm). The second factor studied was the scion size: thick scions (Ø= 6–8 mm); medium scions (Ø= 4–6 mm); thin scions (Ø= 2–4 mm). The highest rate of rose shrubs was obtained with class I rootstocks, and lowest with class III rootstocks. The biggest number of I class shrubs was obtained on class I and class II rootstocks, and from thick scions, and the smallest number with class III rootstocks. The root system development was best with class I and class II rootstocks. The rate of successful grafts and the quality of the shrubs obtained were not affected by the scion size.

Foliar feeding is an effective method of supplying plants with nutrients, much faster than soil fertilization. The effectiveness of this procedure may result from quick penetration and transfer of the applied nutrients inside the plant. The aim of foregoing studies was to assess the effect of foliar nitrogen application upon the yield of fresh and air-dry basil herb of the cultivars: ‘Kasia’, ‘Wala’, ‘Genua Star’ and ‘Opal’, grown in an unheated foil tunnel. Foliar feeding was performed dosing 0.5% urea solution until complete wetting of leaf blade surface. The influence of cultivar and urea application upon the yield and chemical composition of basil herb was demonstrated. The highest concentrations of total nitrogen, potassium, calcium and protein, but also nitrates, were characteristic of ‘Opal’ plants. Among green-leaved cultivars, the highest fresh herb weight was that of ‘Genua Star’. The foliar application of nitrogen increased the weight and yield of fresh herb. It also caused increased concentrations of N-NO3 and N-NH4, K, Ca, compared to control plants.