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Yield stability analysis was based on the results of survey investigations of private farms that had been conducted in the years 1990–2001. Eleven winter wheat cultivars were chosen to the analysis. Particular years of investigations were taken as an environmental factor. On the base of the investigation results six of the studied cultivars were shown to be stable, whereas the others were unstable. Moreover estimation of influence of the particular years (1990–2001) on the cultivation of chosen winter wheat cultivars was performed. The contribution of these years to the G × E interaction was also analyzed. An additional analysis of the G × E interaction for the adjusted values, as related to the reduced effects of cultivation methods and soil conditions on the yield, was performed.

Theoretical and practical effects of winter wheat breeding have been established. The results obtained at the Experimental Variety Trial Stations as well as the inquiry data gathered in production farm in the period 1986–2001 were utilised. A method based on the dependency of yield on age of variety, without referring to a standard variety, was applied. Relationships between yield and a year of variety introduction were analyzed. A linear character of the dependency of yield on the age of variety (number of years after variety release) was revealed. An average value for the breeding effects (0.69%, referring to 47 kg·ha-1) was close to the value established using the method based on indices for a yield-creating value of the varieties (41 kg·ha-1), presented in part I of the paper. A varietal factor determined 42% of the yield increase, and its significance tended to grow up in the course of time. Average yearly increase of the winter wheat yield in the inquired farms, as achieved owing to the introduction of new varieties, was estimated at the level of 40 kg·ha-1, after taking into account the differences in mineral fertilization, soil conditions and intensity of chemical treatment.

In wheat (Triticum aestivum L.), the characters of a spike have the direct or indirect influence on the yield potential of the plant. This paper presents the review of world literature concerning the genetic determinations of the most important characters of a spike, which have become the subjects of introgressions and the morphological markers in many breeding and genetic programmers. Also, they are used to identify species within the genera Triticum L. and to establish the identity of European varieties according to the UPOV convention.

The experiment with forecrops for spring wheat was conducted at the Agricultural Experimental of Uhrusk in the 1997–2002 years. It was set up the randomized blocks in four replications in 10 m2 experimental plots. The grey-brown fertile (rendzina) soil was formed of light loam and weak sandy, and it was classified as a very good rye complex. The experiment included five forecrops for spring wheat: pea, potato, spring wheat (1x), spring wheat (2x), spring wheat (3x), as well as two plant care systems: mechanical and chemical. Pea or potato forecrop increased content of total protein in grain, gluten wet, sedimentation number and grain uniformity in spring wheat. Chemical care of wheat significantly increased the content of total protein in grain and gluten wet as compared with those in spring wheat treated mechanically.

The experiment with rotation systems for spring wheat was conducted at the Agricultural Experimental Station in Uhrusk in the years 2000–2002. It was set performed in four replications in plots 10 x 3.75 m and arranged using the randomized blocks design. The grey-brown rendzina soil consisting of light loam and weak sandy was classified as a very good rye-type soil utility complex. The experiment concerned four crop rotations, with varying proportions of spring wheat (25, 50, 75, 100%), and two plant care systems: basic (harrowing) and intensive (harrowing, herbicides, fungicides). The grain yield of spring wheat, var. Eta, was affected by both weather conditions in the years of studies and the rotation and plant care systems. Spring wheat cultivation in monoculture decreased the grain yield by 36% as compared with the crop rotations at 25–50% of wheat. The application of pesticides increased the grain yield by 6.0% when compared to the basic treatment. Spring wheat cultivation in monoculture decreased the content of total protein in grain, wet gluten, sedimentation value, test weight and grain uniformity in comparison to crop rotation A (25% of wheat) and B (50% of wheat).

Plants of ten cultivars of spring wheat (Triticum aestivum L.) were subjected to soil drought at the heading phase until 50% of water deficit in flag leaves was attained. It has been shown that investigated cultivars differ in their ability to escape dehydration as well as to tolerate dehydration. The highest ability to escape dehydration was developed by cv. Torka, whereas the lowest one was found in cv. Broma. Soil drought enhanced flowering phase in most of the cultivars. The decreased grain weight (by about 34%) and number of grains per spike (by about 44%) resulted in reduction of grain yield (by about 71%). The strongest reduction of grain number has been observed in the florets of 4th order, whereas the lowest one was found in the flowers of the first and second orders. The experiments allowed dividing investigated cultivars into groups of resistant, medium resistant and cultivars susceptible to drought.

Grain protein content is one of the most important factors influencing baking quality of wheat cultivars. Three groups of recombinant lines developed from a cross between spelt and cultivar Elena were investigated in the years 2000, 2001 and 2002 to determine relationships between gliadin electrophoretic spectra and grain protein content. The lines differed in gliadins coded by the chromosome 1B. Two gliadin blocks: Gli B1-6 (spelt type) and Gli B1-1 (Elena type), as well as two individual gliadin bands: S2 (spelt type) i E2 (Elena type) were identified among the analysed genotypes. Analysis of variance proved that protein content of spelt type genotypes (Gli B1-6/S2) was significantly higher than that of Elena type genotypes (Gli B1-1/E2). Recombinant lines that combined spelt and Elena gliadin proteins (Gli B1-6/E2) were characterized by intermediate, but significantly different from parental forms, levels of protein content. The results suggest the existence of the relationships between grain protein content and variability of ω-gliadin subunits. It may be assumed that confirmation of these relationships will make possible to utilize, in the future, the identified gliadin proteins as biochemical markers to reveal the enhanced content of grain protein.

The influence of three dates (15th September, 30th September and 15th October) of sowing of two German cultivars of spelt (Triticum aestivum ssp. spelta): Bauländer Spelz and Schwabenkorn, Swiss cultivar Loge and Belgian cultivar Rouquin on yield components was investigated on the rendzina soil in 1995–1997. It has been demonstrated that the plants of spelt sown in the two first dates showed the highest ability to winter. The effects of the delayed sowing time upon corn yield were less pronounced in cvs Loge and Schwabenkorn than in cvs Bauländer Spelz and Rouquin. Corn yield of spelt sown on 15th or 30th September was higher than that of spelt sown on 15th October.

The aim of this study was to determine the effect of seed dressing on sowing value of spring barley. Barley seeds of five cultivars harvested in 1999 and 2000 were examined. The seeds were treated with fungicides tebuconazole (Raxil) or carboxin + thiuram (Vitavax). In the laboratory tests, seed health, germination capacity and vigour were evaluated. It was found that barley seeds were infested by numerous species of fungi. Among them, the saprophytic fungi: Alternaria alternata, Penicillium spp., Stemphylium spp., Cladosporium spp. and the pathogens: Bipolaris sorokiniana and Fusarium spp. were most often observed. The study has shown that seed treatment reduced the occurrence of microorganisms, especially pathogens. A highly effective fungicide was carboxin + thiuram that reduced the incidence of Bipolaris sorokiniana. It was also more effective than tebuconazole towards microflora. The data of evaluation showed a higher level of seed contamination by B. sorokiniana in brewer's barley than in fodder barley. Germination capacity and vigour depended on seed treatment and cultivars.

The aim of this study was to determine the effects of seed dressing on field emergence and yield of spring barley. The field experiment was conducted in the years 2000–2001 in RadzikĂłw in plots of 10 m2 each. Prior to sowing, the seeds of spring barley were treated with fungicides tebuconazole (Raxil) or carboxin + thiuram (Vitavax). Untreated seeds were used in a control variant. In general, a medium level of the field emergence was observed.  Brewer’s barley achieved a higher level of emergence than did fodder barley, but the differences between the cultivars were rather small. The yielding of spring barley was considerably affected by weather conditions during the vegetation period as well as by cultivar features. The yield of grain per plot obtained in 2000 was twice as high as that obtained in 2001 for all the cultivars under study. Seed dressing, especially with Vitavax, resulted in slight increasing the yield.

The grain of spring barley (cultivars Rodos, Rambo, Start) from a two — year field experiment was used to study the effect of the cultivation system (monoculture, crop rotation) on the content of factors limiting the feed value of grain, i.e. crude fibre and its fractions. It was found that the cultivation system and the year of plant harvesting effected the level of the antidietary factors. No significant differences between varieties were found in the content of the determined components. In the case of crop rotation an increase in crude fibre and all its fractions was observed.

The malting quality of 353 home-bred cultivars and lines of spring barley was evaluated in the years 1999–2001. Barley grain came from the pre-preliminary and preliminary experiments performed each year at three locations. Coefficients of heritability were determined for 1000 grains, grain filling, total grain protein, and those, for percentage of total and soluble protein of the malt, Kolbach index, extractability, wort viscosity, diastatic power and final fermentation degree were determined after micromalting. The influence of environment was high for malt protein and wort viscosity The heritability of the characters was high for 1000 grains weight, diastatic power and soluble protein of malt. Advantageous or disadvantageous correlations between the traits, as important from a practical point of view, were determined. The obtained results indicate a significant influence of genotype and environment for breeding quality of spring barley.

The seed sowing value of seeds of three generations of winter triticale from different environmental conditions was compared. The field experiment with the use of distance isolation was performed at three locations (Lublin, Olsztyn, Sandomierz) in the years 1997–2000. The initial material that was stored in the long-term storage of Gene Bank was, sown as a control. The germination capacity and vigour (length of plumula and dry weight of seedling) were analysed. The germination capacity of both varieties was different. In contrast, no difference in seed vigour was found. No decrease in the seed sowing value of winter triticale was observed following three-year seed multiplication.

Resistance to Fusarium head blight of somaclonal lines (generations R1–R3) generated from 20 parental genotypes was studied. Heads were artificially inoculated with Fusarium culmorum isolates. Significant variation among parental genotypes in the resistance and tolerance to Fusarium head blight was found. Somaclonal lines generated from different parental genotypes (of different resistance) and the lines generated from different calli of the same parental genotype varied significantly in the level of resistance. Mean levels of resistance and tolerance for consecutive generations of lines did not differ significantly, which proved the stability of reaction of the lines to head blight. The increase or decrease of resistance to the level determined for parental genotype was observed only with some lines. The results presented in the paper show that the use of somaclonal variation can result in the stable improvement of the genotype resistance.

Merely two tetraploid rye plants were found among 128 progeny plants of four F1 hybrids between tetraploid triticale (2n = 28) and tetraploid rye (4n = 28). The remained plants were triticales, tetraploid with exception of one individual with 38 chromosomes. The numbers of wheat and rye chromosomes were precisely determined, with the Giemsa banding technique, for 57 plants, including 32 true F2 obtained following the F1 selfing. Over 90% of the tetraploid triticales had full complement of 14 wheat chromosomes, in the remained plants one or two wheat chromosomes were substituted for the rye ones. The substitution plants with a higher proportion of rye chromosomes were lacking. There were also no cases of new intergenomic translocations different to those present in the parental forms. In relation to the theoretical distribution, based on the assumptions on independent segregation for wheat-rye pairs of homoeologues and on equal survival of all types of gametes and zygotes, the over-representation of the plants with 14 wheat chromosomes was 16000 — fold. The influence of a mistake at crossing could be excluded because of the normal segregation of a cytogenetically marked version of the 1R rye chromosome from the rye parent. Owing to a relatively high fertility of the F1 generation (40–45 seeds per spike), the over-representation of triticales with the whole wheat genome could not be statistically explained by zygotic or/and gametic selection. The results suggest group segregation of wheat chromosomes in meiosis, rather than of the assumed independent segregation of each wheat-rye pair. The low frequency of rye plants could be related to self-incompatibility of karyotypes without the complement of wheat chromosomes.

The aim of the study was to estimate direct and indirect effects of six traits on grain yield per plot in strains and cultivars of winter rye, investigated in field trials in 1999 and 2000. The study was carried out on 112 forms (56 in each year) in 7 localities. The path-coefficient analysis carried the make the genotypic correlations between of investigated the traits. Grain yield was found to be influenced by the plant height, uniformity, date of heading, pollinating ability, resistance to lodging and brown rust. Path-coefficient analysis showed a very strong direct effect of pollination ability on grain yield, at P27(1999) = -1,701 and P27(2000) = -0,988. The above effects significantly affected genotypic correlation between grain yield and pollination ability in both years of study (rG(1999) = -0,43* and rG(2000) = -0,71**). A positive genotypic correlation was also found between plant uniformity and grain yield (rG(1999) = 0.23 and rG(2000) = 0.47*), although direct effects on yield were negative in both years of the study (P47(1999) = -0.885, and P47(2000) = -0.454). Multiple determination coefficients R2(1999) = 90.8% and R2(2000)=63,1% were high.

The studies were carried out in the years 1992–1994 in plots formed of different types of soil taken from the fields representing five soil complexes. The highest yield of winter rye grain was obtained on the rye very good or good complexes. Comparatively higher yield from the wheat very good complex was recorded only once, namely in the year in which the environmental conditions were not suitable enough for winter rye growth and yielding. The grain yield was found to increase with increasing of a number of tillers per plant. The characters determining grain yield per ear depended mainly on the height of a culm, whereas a number of tillers had only a slight effect.

Long-term storage survey of winter oilseed rape started in 1987. Seeds of the moisture content of about 8% were vacuum packed in glass containers and placed in a chamber at 1°C. After 15 years of storage the highest germination capacity index was found for the following varieties — SV 7473/73 — 94, Erra — 93, Ridana — 92 and Parapluje — 91.

The paper presents a role of yield components in creating spring oilseed rape yield under different conditions of pest control and nitrogen application. The relationships between yield and its components were estimated using the path coefficient analysis. Pest control resulted in saving 5.9 dt of seed per 1 ha. In no case the increasing of nitrogen doses stimulated a compensation of oilseed rape after injuries caused by pests. Rape reacted to increasing nitrogen doses, up to the highest one, by the rise of seed yield. The effectiveness of nitrogen application, as evaluated for 1 kg, was highest at the range up to 80 kg N×ha-1. Higher doses resulted in over 2-fold decrease of the effectiveness. Yield of rape protected against pests was positively correlated with a number of both siliques per 1 m2 and seeds per silique, whereas it was negatively correlated with 1000 seeds weight. In contrast, the yield of rape that was not protected was substantially affected by a number of seeds per silique. At a low level of nitrogen application (≤ 80 kg×ha-1), rape yield was created by all the components studied (in the case of 1000 seeds weight the path coefficient appeared to be negative). Meanwhile, at large doses of nitrogen (120–160 kg×ha-1), only the number of seeds per silique was found to have a direct effect on spring oilseed rape yield.

Field trials were conducted in the years 1999–2001 at the Experimental Station in Błonie-Topola. Five maize cultivars: Janna, Dragon, Mieszko, LG 2244 and Costella at four sowing densities (70, 90, 110 and 130 thousand grains per 1 ha) were tested. The yield structure was analyzed on samples of ten cobs per plot. The impact of yield components on absolute (dt/ha) and relative (%) differences in grain yield, as related to both the lowest plant density and lowest yield, were estimated as described by Rudnicki (2000). Higher yielding of maize in the conditions of a higher plant density was due to a higher number of cobs per 1 m2, which consequently increased the mean yield of grains by 11.6 dt/ha (12.4%). However, such a plant density caused both the reduction of a number of grains per cob and the weight of 1000 grains, which, in turn, decreased the total grain yield by 2.1 and 1.1 dt/ha (2.3 and 1.1%), respectively. Higher grain yield in four varieties (av. by 17.6 dt/ha; 20.6%), as compared with that in var. Janna, resulted from a higher number of grains per cob (by 9.8 dt/ha; 11.5%), weight of a thousand grains (by 4.0 dt/ha; 4.7%), as well as from a higher number of cobs per 1 m2 (by 3.8 dt/ha; 4.4%). A contribution of particular yield components to the total grain yield in the evaluated varieties was different. Both, a small number of grains per cob in var. Dragon and low weight of 1000 grains in var. Mieszko caused the substantial reduction of their yield, as compared with varieties Costella and LG 2244.

Analysis of stability was based on the results of survey investigation of private farms, which was conducted in the years 1986–2001. A scheme of the survey was prepared by the Plant Breeding and Acclimatization Institute at RadzikĂłw. The survey included 143 cultivars of these, nine were chosen, which had been cultivated successively for the whole 16-years period. Particular years of the investigations were taken as different environments. On the base of the survey results four of the studied cultivars were found to be stable, whereas the others appeared to be unstable or unpredictable. Selection of stable cultivars is very important for preparing standards used in comparative analyses. The analysis of stability was performed using a software SERGEN 3.

The analysis of breeding progress in potato production was performed based on the results of the survey investigations carried out in commercial farms in the years 1986–2001. A modified Feyerherm’s method was applied. Significant increase of breeding effects in agriculture practice was found. A considerable contribution of cultivar structure optimalization to the yield-creating potential of the potato has been demonstrated. Breeding progress is not often accompanied with technology improvement. Hence, its effects can only contribute to yield level stabilization. Utilization of the yield-creating potential of potato cultivars in the investigated farms was found unsatisfied. Only the yield potential of medium late and late cultivars can be considered to be utilized at an acceptable level.

Twenty four potato genotypes obtained in a frame of the development of parental lines for breeding of potato cultivars suitable for chip processing and four cultivars differing in suitability for chip processing were evaluated at MłochĂłw in 1999–2001 for starch content and chip colour. Combined analysis of variance indicated significant differentiation between genotypes and years of the test for all traits under consideration. High differences among treatments were also found in the genotype × year interaction. The three selections (M-62705, M-62724, M-62774) combining light chip colour after cold storage and stability of this trait with increased starch content as well as the stability of starch content were identified. A moderate correlations were observed between mean values of chip colour and stability parameters: Shukla’s “stability variance” (S2i) and coefficient of variation (V%), whereas no such association could be observed in the case of starch content.

In the years 1981–1992, five series of experiments on tuber dormancy of 23 potato cultivars (9 mid-early and 14 late maturing) were performed at the Institute of Potato Research in Jadwisin. To assess the length of a dormancy period, three estimates were used:

The evaluation of the effects of seed dressing by a fungicyde + insecticide mixture (pencycuron + imidacloprid) was performed in 1999-2001 at the IHAR Branch Division Bonin and at a private farm Niekłonice. The experiments involved three potato cultivars: Mila (1999), Orlik (2000) and Cedron (2001), and were carried out in four replications under field conditions. Seed tubers were dressed using a prototype device for seed dressing that was set up onto a planting machine. The results obtained showed high efficacy of the dressing in protection of potato plants against colorado beetle, black scurf and wireworms during the whole vegetation period. A positive effect of the treatment on both tuber quality and yield was also observed.

Regression analysis was applied to evaluate the dependencies between the level of potato plantation weeding and total and commercial yield of tubers achieved in 1996–1998 in the field experiment performed on the soil formed of light loamy sands classified as a good rye complex. Experimental methods and study conditions were described in Part I of the paper. Significant dependence of both the total and commercial tuber yield on fresh and dry matter of weeds determined before tuber harvest was found. The relationship between the decrease of the total or commercial yield and the increase of the content of dry matter of weeds was of parabolic character in each control system. Air-dry matter of weeds appeared to be a more estimate than fresh matter (or weed number) to assess yield losses. It can be used to determine weed threshold values for potato crops.

The results were obtained in the years 1996–1998 in a field experiment carried out on a soil formed of light loamy sands, representing a good rye complex. Randomized subblocks at 3 replications were applied. The effects of three factors were examined: I – different cultivation technologies, including: a) conventional technology as a control variant, b) the use of polyethylene sheeting, c) the use of polypropylene sheeting, d) double shield using both polyethylene and polypropylene sheeting; II – different methods of potato cultivation: a) mechanical, b) mechanical-chemical with Afalon 50WP at a dose of 2 kg ∙ ha -1, c) with herbicide Racer EC at a dose of 2l ∙ ha -1, d) with herbicide mixture Afalon 50 WP + Command 480 EC at a dose of 1 kg + 0.2 l (respectively) ∙ ha –1; III – different potato cultivars: Aster and Drop. Covering of the soil by both cultivated plants and weeds as well as damage to the plants caused by herbicides were recorded throughout the vegetation period. The mechanical-chemical methods of weed control, as compared with the mechanical cultivation alone, resulted in considerable reduction of both monocotyledonous and dicotyledonous weeds as well as in increasing the ratio of soil covering with cultivated plants. The use of shields was found to enhance the development of undesirable phytotoxic symptoms in potato plants. The technologies using either polypropylene or polyethylene sheeting applied as a cover appeared to be safer than that using a double shield containing both a polypropylene and polyethylene sheet.

The results presented in this paper were obtained in the field experiment carried out in the years 1996–1998 on a soil formed of light loamy sands representing a good rye complex. The schema of the investigations was presented in. Part I of the paper. In this part fresh and air dry weed mass, number of monocotyledonous and dicotyledonous weeds and their floristic species composition before and after plant shading and before potato maturity. Both fresh and dry weed mass were reduced most effectively by the mechanical-chemical cultivation with herbicide Afalon 50 WP. This preparation also showed a high efficiency to control monocotyledonous weeds as well as and some dicotyledonous ones like: Centaurea cyanus, Stellaria media, Anagalis arvensis. In turn, the mixture of Afalon 50 WP + Command 480 EC was found to be effective in reducing a broad spectrum of dicotyledonous weeds, such as Chenopodium album, Raphanus raphanistrum, Vicia tetrasperma, Cirsium arvense, Galeopsis tetrahit, Spergula arvensis, Veronica hederaefolia, Myosotis arvensis.

In modern storage houses potatoes can be stored in a bulk up to a height of 5 m. In the lower layer the potatoes are subjected to a strong pressure force. After storage lasting 7 months potatoes often become deformed and pressure-bruising. The experiment was performed on 4 potato cultivars: Danusia, Mila, Kuba, and Triada, which were squeezed in press-boxes simulating the pile height of 2.5 (box A) and 5.0 m (box B), and in the control box with no pressure (box C). The boxes with ventilating holes were placed in a storage room in which the temperature of 4°C, as recommended for table potatoes, was maintained throughout the experiment. After a 7-month storage period, the surface of the biggest pressure-bruise on the tuber, natural losses and the length of sprouts were evaluated. The pressure-bruise was clearly visible on the tubers of all investigated cultivars. In box B, the mean surface of the largest pressure-bruise for 4 cultivars was 413 mm2, whereas that in box A measured 328 mm2. Natural losses in particular cultivars were the smallest in box B. They were significantly larger in box A and in a control box C. Their average length for 4 cultivars was 12.8 mm. In a control box the mean length of sprouts was 9.8 mm. No changes in the form of parenchyma darkening at the site of the pressure-bruise were observed either directly after treatment or after further 4 days of storage.

An influence of presprouting, mineral oil application and different methods of haulm destruction on tuber infection by common scab and black scurf was evaluated in the years 1999–2001. The trials were carried out in the potato fields in Bonin near Koszalin. They involved mid-early potato cultivars Mila and Balbina. The weather conditions during the growing seasons differed between the years. Both the amount of rain and the rainfall distribution as well as soil temperatures largely influenced the incidence of tuber diseases. Presprouting resulted in a significant increase of the proportion of black scurf-infected tubers, but reduced the occurrence of common scab. Application of mineral oil during the growing seasons increased the incidence of black scurf, reduced the infection with common scab and diminished the proportion of tubers with no disease symptoms within the yield. No significant effect of the treatments used to destroy haulm upon the occurrence of the surveyed diseases within the tubers was found.

The preliminary evaluation of resistance stability for late blight (Phytophthora infestans) in a group of 22 Polish potato cultivars is presented. The tested cultivars differed in their resistance level, maturity and origin. The evaluation of resistance stability was carried out in the years 2001–2002 under strong natural infection pressure at four locations in central and southeastern Poland. The area under disease progress curve (rAUDPC) for each cultivar was calculated on the basis of field observations. The field evaluation of stability was supplemented with evaluation of resistance of artificially inoculated detached leaflets. The area under disease progress curve was significantly influenced by the tested factors (genotypes, years and locations), and genotype-environment interaction (G ´ E). To evaluate stability of reaction, tree statistical parameters were used. These parameters allowed to distinguish four groups which differed in stability of resistance. The group with the most stable reaction consisted of cvs. Jasia and Klepa (resistant according to assessment by Research Centre for Cultivar Testing, RCCT), Hinga and Bzura (highly resistant according to RCCT). The cultivar Jasia deserves special attention. Characteristic of this cultivar is the highest stability (very low variance of stability). No infection could be observed in the leaflet tests in any the two years of studies.

The field experiment was carried out in 1993–1995 at the Agricultural Experimental Station in Zawady on the soil of strong grain-pasture complex using the split-block method. The effects of the mass of overploughed cover crop (post-harvest residue, whole biomass) and the form of organic fertilization (control without organic fertilization, farmyard manure, undersown cover crops: red clover, black medic, Italian ryegrass and red clover + Italian ryegrass, black medic + Italian ryegrass) on concentration of dry matter and macroelements in roots and leaves of sugar beet were evaluated. The influence of farmyard manure with undersown cover crop on concentration of dry matter and macroelements in sugar beet was also compared. Fertilization of the soil using the whole biomass as compared with post-harvest residue alone caused essential decrease of the quantity of dry mass in roots and leaves. Moreover essential increase of concentration of total nitrogen and potassium in roots and leaves and of calcium in leaves of sugar beet was observed. Irrespective of the amount of over ploughed cover crop the applied forms of organic fertilizers increased in most cases the concentration of dry matter, total nitrogen, potassium, calcium and sodium in sugar beet roots and leaves and that of phosphorus in roots, as well as the magnesium content of leaves. The effects the post-harvest residue and the whole biomass of undersown cover crop, as compared with those of farmyard manure, on concentration of dry mass, total nitrogen and potassium in roots and leaves as well as on the concentration of calcium, magnesium and sodium in leaves could differ significantly.

The study was conducted in climatic chambers at the Institute of Soil Science and Plant Cultivation in Puławy. The experimental design included two factors: two morphologically different varieties of white lupine: Bardo (traditional form) and Katon (determinate form), and differentiated soil moisture: 30%, 50% and 70% of field water capacity. Decreased water content of the soil strongly reduced both the development and yielding of white lupine. The lowest yield was found for var. Katon that was cultivated at the lowest soil moisture (30% of field water capacity). The highest yield was obtained with var. Bardo grown at the optimal soil moisture (70% of field water capacity). The reduction of seeds yield, found for plants grown under conditions of lower soil moisture, resulted from a lower pods density per plant as well as lower number of seeds per plant. Determinate lupine var. Katon was more susceptible to water deficit in the soil than was traditional var. Bardo.

A field experiment was carried out in order to evaluate the yield, chemical composition and nutrimental value of two red clover morphotypes (new long-flowered strains 9 and 84) and cv. Nike. It was conducted in a 2-year period (1999–2000). In the successive harvest years, cv. Nike gave the forage yield of 16.3 and 10.1 kg/m2, and the yield of new morphotypes averaged 85 and 61% of these values, respectively. Leaves of long-flowered strains provided a larger part (46.6 and 51.8%, respectively) of the total forage yield compared with that of cv. Nike (44.2%). Protein content of leaves in long-flowered strains (24.2 and 23.9%, respectively) was similar to that in cv. Nike (23.5%). The stems of the strains contained slightly more protein than the stems of cv. Nike (12.3 and 13.7% vs. 11.5%). Red clover leaves were a richer source of essential amino acids than stems, and this difference was reflected by the respective EAAI values (leaves: 70.4–70.8; stems: 53.7–59.4). A negative relationship between annual forage yield and forage protein content, and a positive relationship between annual forage yield and forage lysine content, were found.

The biological traits and their effects on turf performance and seed value of Poa pratensis have been described based on 91 positions of Polish and foreign topic literature. The apomixity phenomenon and its influence on a low variability of the biological traits were also taken into consideration. Turf performance of Kentucky bluegrass found to be determined by such traits as: colour, density of turf, leaf fineness and slow re-growth. Seed yield can depend on a number of generative tillers, structure of inflorescent, thousand seed weight and phenological traits. Diseases such as rust, powdery mildew and leaf spot may significantly decrease both the value of turf and seed yield. Influence of the main traits on an economical value of Poa pratensis cultivars is discussed.

Resistance against leaf spot and melting out caused by Drechslera poae (Baudys) Shoemaker is crucial for commercial value of new cultivars of Kentucky bluegrass. Breeding for resistance against this disease is a major goal of most breeding programs. A correlation between plant height and resistance was demonstrated. There was no relationship between the resistance to leaf spot and melting out and the width of leaf blade.

The importance of turf and forage grasses seed production has significantly increased during last years. Therefore, seed yield and disease resistance are crucial for commercial value of new cultivars. Integrated Disease Management is one of the most important activities of Integrated Plant Management. In this review, the contribution of integrated disease management to the enhancement of seed potential in coal-season perennial grasses is described.

The aim of the studies was to compare the effects of different plant spacing on tobacco yield and market value as well as important qualitative features of four varieties representing type Virginia: Wiślica, Wisana, Wika and Wiecha. The field experiments designed as the randomized blocks were carried out in the years 1997-1998. The qualitative analysis of tobacco leaves included assessment of composition of soluble carbohydrates and true proteins, weight of 1 dm2 of dried leaves and amount of the main vein tissue (%) within the foliage. Plant spacing was found to influence considerably both yield and leaf quality of Virginia tobacco. The yield and market value of plants grown at the spacing 70 x 40 cm were higher than those of plants grown at 90 x 40 cm. However, the leaves of higher quality, characterized by a high content of carbohydrates and a relatively low content of proteins, were produced by the plants grown at 90 x 40 cm. Based on the results concerning the yield and quality of raw material, two tobacco varieties: Wiślica and Wika can be recommended for cultivation.

Withania somnifera, a subtropical plant from Solanaceae family, is a very interesting medicinal species. In the regions of its natural occurrence, especially in India, the root of Withania (Radix Withaniae) has been widely used as an energizing, immunostimulating and adaptogenic drug. The aim of experiments carried out in the greenhouses of Agricultural University in Warsaw in 1997–1999, was to verify the hypothesis that: the observed in Withania lack of response to nitrogen fertilization is not a result of low demand for nitrogen, but it is caused by the pH of soils in which the plant has been grown in India. The experimental plants were grown in peat substrate with pH adjusted to 5, 6 and 7. Nitrogen contents were: 100, 200, 300, 350 and 400 mg/dm3, while the constant phosphorus and potassium levels were set to 80 and 300 mg/dm3, respectively. The results suggest that Withania somnifera prefers acidic soils. The highest yields of herb and roots, as well as withaferine A content and yield, were obtained at pH 5. The plants took up significantly more minerals (nitrogen, potassium and phosphorus) than the ones grown at a higher pH of soil. Withania somnifera seems to have high demand for nitrogen, and the observed lack of reaction to nitrogen fertilization is probably due to inappropriate pH of soils, on which it is grown in India.