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Inbred lines production in rye (Secale cereale L.) with the classical breeding procedure is a difficult and time consuming task. With use of in vitro culture techniques for obtaining doubled haploid plants of rye it can be done in a shorter time. In cereals, for the haploid induction the androgenesis (anther culture and isolation microspores) and elimination of chromosomes are widely used. The most important factors influencing the androgenic capacity are: growth of donor plant material, genotype, the initial treatment of spikes and anthers, the stage of microspores development, the medium and culture condition. Rye (Secale cereale L.) is a species in which induction of haploids in vitro anther cultures causes many problems. The most frequent occurring problems are low percentage of regenerated plants and high participation albinotic plants.

The effect seed priming in water and two solid substances of two maize hybrids was determined. In laboratory seed priming effected, first of all, on acceleration of germination speed. Effectiveness of seed priming in solid substances (solid matrix priming — SMP) was higher than in water. Field emergence after SMP of seeds was higher by 6.7 and 6.5% in comparison to control seeds. Plants emerged faster by 1.6 to 2.1 days. Yield of plant dry matter of variety Duet, after seeds priming in water and solid substances increased from 13.7 to 54.6 g (7.3–29.1%). Increase of kernels yield of KLG 22-10 variety, as a result of seed priming was from 4.1 dt/ha to 8.6 dt/ha (8.0–16.8%) as compared to control seeds.

Measurements of weight losses of leaves cut off from plants of 44 potato cultivars were carried out in 1988–1995. Leaves were sampled at 7.00, 12,00 and 17.00 and weighted 3 times: just after cutting than 1 and 2 hours after cutting. Leaf weight losses 1 and 2 hours after cutting and index W being the proportion of these two values were assessed. Leaf weight losses and index W were the highest in the morning and decrease during the day. Significant influence of humidity and temperature of air was also observed. There were found a highly significant differences among cultivars for all parameters measured. The method seems to be quite good for stomatal efficiency assessment to compare genotypes for their defence ability against water losses from tissue.

The three-year (1998–2000) field experiments were carried out in order to establish the optimal N fertilization rates for Aksamitka and Gloria varieties cultivated for early harvest (60 and 75 days after planting) and at full maturity. The trials were located in Jadwisin, Division of the Plant Breeding and Acclimatization Institute and in Stare Olesno, Experimental Station of the Plant Breeding and Acclimatization Institute. It was stated that 60 days after planting the very early variety Gloria yielded better than early variety Aksamitka; 75 days after planting both varieties yielded at the same level and at full maturity the Aksamitka variety yielded higher than Gloria. On the basis of regression analysis maximal and recommended nitrogen rates for both varieties harvested at particular term were established. Recommended rates were from 30 to 40 kg N×ha-1 lower than maximal one and for successive harvest dates of Aksamitka variety were at the rate of 50, 70, 130 kg N×ha-1 and of Gloria 50, 80, 120 kg N×ha-1 respectively. Five weeks of seed presprouting had favourable effect on yield of both varieties at all harvests.

The effect of growth regulators on the structure of potato tubers yield was evaluated in field experiment carried out in 1993–1995 on podsoloic soil derived from light loam in Parczew. The experiment was designed as sub-blocks in inter-related system, with three replications. The first class factor were growth regulators (Mival at concentration of 0.05%, Moddus ME — 0.2% and distilled water as a control), the second class factor were two date of application of growth regulators (before planting and before flowering) and third class factor composed of five potato cultivars (Drop — very early, Perkoz — early, Irga — medium early, Grot — medium late and Elba — late) Manuring and mineral fertilization were applied at the rate of 100 kg N, 100 kg P2O5, 150 kg K2O and 250 dt·ha-1 of farm manure. Growth regulators contributed to the decrease of weight share of tubers 3–4 cm in diameter with simultaneous increase of tubers 4–5 cm and >6 cm in diameter in total yield. Additionally, applied growth regulators caused increase of number and weight of tubers per plant and seed potato yield in comparison with control.

The susceptibility of tuber of breeding potato clones to after-wounding blackspot was tested in the years 1997–1999. Rotary simulator of natural potato tuber internal damage was used. The blackspot of tuber tissue depended mostly on a genotype. Years had smaller effect on this character. Testing of the potato tuber for the potato tubers resistance to after-wounding blackspot with a rotary simulator of damage allowed to discard very susceptible breeding material.

The field experiments set up on microplots of 6 soil types was carried out in 1997–2000 at Jadwisin Branch of Plant Breeding and Acclimatization Institute. Diversified soil moisture was achieved by irrigation from the end of emergence to full blooming. Two types of N- fertilizers (of basic and acidic physiological reaction) were applied. In 1997 and 1998 the CaCO3 at the amount of corresponding to 1/2 of hydrolytic acidity was applied after plant emergence, whereas in 1999 and 2000 foliar application of CaNO3 was used. The plants were sprayed 5-times every 7 days started full of budding. Under natural weather conditions tubers infection with common scab was significantly differed. The moisture and soil type were the factors with the highest effect on intensification of disease symptoms. Four irrigation, each time with 30 mm of water applied from the end of emergence to full blooming improved soil moisture and significantly reduced tubers infection. The regression and correlation analysis were performed to evaluate interdependence between soil moisture and tubers infection. On lighter soils, i.e. light loamy sand and heavy loamy sand, significant correlation coefficients occurred between their moisture and tubers infection (-0.8908 and -0.8721 respectively). The most favourable conditions for the disease development on such soils occurred at the lowest moisture, approximately 4%. Under conditions of heavy loam soil, tubers were strongly infected at the moisture of 10%. Both lower and higher moisture of that soil produce limiting effect on disease development. Application of light basic N-fertilizer under conditions of natural precipitation caused increase of scab infection. Foliar application of CaNO3 did not changed level of infection with common scab. The effect of liming applied after emergence on tuber infection with common scab was inconsistent. The interaction between this factor and irrigation on different soils was observed.

The gene lp, governing long raceme peduncle and great number of flowers in inflorescence, was used for improvement of seed yield potentials of Radius variety. The breeding stock of variety exhibiting superior pod and seed setting was back crossed to the donor of lp gene — mutant line No. 2002/1. After two cycles of back cross 7 long racemed lines were obtained. Five lines were selected to form the new synthetic variety RAH 100. Field trials demonstrated 15–20% higher seed yield of this variety in comparison with the best short racemed standard cultivars.

The 1997–1999 field experiment was laid out as a randomized block design at the Mochełek Experimental Station. Four following densities 25, 50, 75 and 100 germinating seed per m2 of the Bardo traditional and R-525 — self-completing white lupin varieties were sown on 3rd, 4th April and 31rd of March for the respective years of tests. Average seed yield of Bardo was 3.17 t×ha-1 and 2.39 t×ha-1 of R-525. Net seed yield range from 1.86 t×ha-1 to 3.12 t×ha-1 for Bardo and from 0.52 to 3.26 t×ha-1 for R-525 respectively for the lowest and highest plant densities prior to harvest. Bardo seed yield increased significantly up to 75 plants per m2, while R-525 — up to 97 plants per m2. An equal seed yields of both varieties were obtained at 111 plants per m2. Along with the increase of plant density, the highest reduction of number of pods, seeds and weight of seeds developed on branches and per plant was observed for Bardo. There was no significant correlation between the yield components and plant density for R-525 — self-completing variety. Healthier seeds were harvested from higher plant densities, especially for self-completing variety, while higher germination capacity seeds — from lower plant density, especially for traditional growth type variety.

The results of field experiment conducted in 1996–1998 on wheat soil complex were take to assess usefulness of pea varieties for mixture crop with spring barley. Six multicropping characteristics were considered to estimate usefulness of 16 pea varieties according to multi-criteria analysis. Parameters together with annotated to them weighting values were following: mixtures yield (30), stability of mixture yield (15), yield of pea variety in mixture (15), stability of pea yield (10), lodging resistance (25) uniformity of maturation of pea and barley in mixture (5). Ranking list of varieties was set up with the use of four degree scale. Agra and Dawo were pea varieties of the highest usefulness for mixture with spring barley. The second group of average usefulness consisted of nine varieties, among them Albatros, Grapis, Pelikan, Agat, Kwestor, Perła, Piast, Rubin, Sol, Tegma. Finally, varieties Eroika, Turkan, Kama i Karat showed the lowest usefulness.

The results of field experiment conducted in 1996–1998 on wheat soil complex were take to assess usefulness of 16 pea varieties for mixture crop with spring triticale Migo. Multivariate analysis of usefulness of pea varieties for mixture with spring triticale was based on the following six multicroping characteristics of different weighting values: mixtures yield, stability of mixture yield, yield of pea variety in mixture, stability of pea yield, lodging resistance uniformity of maturation of pea and triticale in mixture. Tested pea varieties as a components of triticale in mixture crop revealed both positive and negative features and because of that multivariate analysis showed small differentiation of usefulness among pea varieties for mixtures. Piast, Perła, Agra and Kama varieties were relatively the best varieties, while Grapis, Kwestor, Dawo, Sol and Rubin were less matching ones.

Examined soybean collection was obtained from the National Centre of Plant Genetic Resources of the Plant Breeding and Acclimatization Institute at RadzikĂłw. In this paper statistical methods such as correlation analysis and factor analysis were used to detect the relationships between 13 tested traits and for grouping closely related traits in classes and in groups of early and late maturing accessions of soybean collection. There was very close relationship between productivity traits (seed weight, seed number and pod number per plant). Those relationships were confirmed by factor analysis. Calculated principal components connected with mentioned above productivity traits explained in the highest degree total variability of examined traits in all classes of soybean collection accessions.

The objective of this study was to determine the effect of initial seed quality on field emergence, yield, yield components and seed quality of the next generation of faba bean, variety Tom and strain STH 494 (now variety Titus). Artificially aged seeds (0, 1,2,3 days at 45–47°C) were planted in 1998 and 1999 in the field at Plant Breeding and Acclimatization Institute, RadzikĂłw. Percent emergence decreased with increasing seed deterioration, and in 1999 slower rate of emergence and less top growth was observed. Decreasing seed quality culminated in lower yield, substantial for seeds aged for 3 days (by 25 and 40%, respectively in 1998 and 1999), comparing to non-aged material. Decreased seed yield was attributed to fewer pods produced per plant. There were no differences between quality of seeds harvested from plants derived from artificially aged and non-aged seeds.

The aim of the work was to find out the interaction between tannin content and standard germination, vigour and seed health as well as to determine the influence of tannin content in seeds on field emergence, plants health, seed yield and its components. Field and laboratory experiments were performed on six different faba bean genotypes derived from harvests of three consecutive years 1998, 1999 and 2000. Seeds of low tannin content, commonly considered as tannin less, — from 0,03 to 0,14% (Caspar i BKSK 1074) and high tannin content genotypes – from 0,88 to 1,69% in dry matter (Rajan, Titus, Tim, Bronto) were chosen. In laboratory experiments evaluation of chemical components, standard germination, vigour and seed health was done. In field conditions the number of plant emergence, plants health, yield and their components were determined. Seeds with low tannin content, dependent on year, germinated poorer (circa 12%), showed lower (circa 10%) field emergence, and in general were characterized with lower vigour than high tannin ones. Health status of low tannin content seed was weaker than that of high content. However the results of standard germination (r = 0,64), conductivity (r = -0,59) and cold-test (r = 0,52) significantly correlated with tannin content. The results suggested that the seeds of low tannin content not only germinated poorer but also were less resistant to suboptimal environmental conditions. In conclusion, it may be stated that influence of tannin content on germination, healthy status and tolerance to environmental stress of faba bean seeds seems to be significant with some variation depending on year of harvest.

The topics presented at the 26th ISTA Congress, held in

Transgenic cultivars of major crops start to play more and more important role in agriculture. The economic importance of transgenic cultivars come from their improved quality characteristics and resistance to pest and diseases. This paper present updated information about procedures of registration of transgenic cultivars in Poland. All aspect of Polish law in relation to registration and cultivation of transgenic cultivars are discussed, especially in relation to environment and human health protection. The role of The Research Centre for Cultivar Testing (COBORU) in implementation of Polish law concerning transgenic cultivars is described.

Interspecific and intergeneric hybridization is a method of high importance in modern plant breeding. The goal of distant hybridization is introduction of genes to breeding materials from wild species, which code for resistance to non-favourable agricultural conditions and to pathogenic factors. In course of distant hybridization conditions may occur for formation of apomictic embryos, as well as for elimination of the whole genome of one partner or a part of chromosomes of one or both partners. For this reason, it is important to verify genetic status of arising seedlings or regenerants as early as possible. Such verification can be performed using markers established earlier by means of diverse methods. In this paper several methods of verification are discussed based on morphological, cytological and molecular markers.

In the years 1998–2000 experiments were conducted with purpose to determine requirements of some new winter wheat strains to main agrotechnical factors: sowing term, sowing density and nitrogen fertilization. Differences were shown in response of the strains to the factors and grouping of the wheat objects was performed. As regards to the response to sowing term, the examined strains were classified into three groups: the first represented by one strain sensitive to delay of sowing (BOA 397), the second group with strains tolerant to 14 days delay of sowing term (SMH 2297, SMH 2497, SMH 3398 and SMH 3498) and the third group of strains insensitive to the sowing delay (AND 2298 and MIB 798). As regards to the response to sowing density, the strains were classified into two groups: the first one requiring low sowing density (AND 2298, MIB 798, SMH 2497, SMH 3398) and the second one requiring medium sowing density (BOA 397, SMH 2297 and SMH 3498). As regards to the response to nitrogen fertilization, the strains were classified into two groups: one requiring a medium level of fertilization (AND 2298, MIB 798, SMH 2497, SMH 3398) and the other one for wheats requiring high nitrogen doses (BOA 397, SMH 2297, SMH 3498).

Trials were conducted with four winter wheat varieties (Kobra, Roma, Juna, Elena) grown in the years 1998–2000 on fields of a long-term crop rotation experiment. Response of the varieties was investigated to four different crop production systems defined as ecological, conventional, integrated and monoculture. The tested varieties differed in plant morphology, susceptibility to diseases and quality characteristics. Yield and some parameters of plant growth and crop canopy were analyzed. The highest differences of the investigated traits were recorded for the ecological system of crop production. Resistance to leaf diseases and competitiveness in relation to weeds were the main factors causing the differences within this system.

Aluminium toxicity is an important factor limiting wheat production on acid soils. The purpose of this research was to find mode of inheritance of tolerance to aluminium toxicity and to find new sources of tolerance different from that represented by the Brazilian cultivar BH-1146. Inheritance of tolerance to aluminium toxicity in Carazinho (BRA), Ruivo Tardio A (PRT), Trigo des Acores (PRT) and Barbela PI 185700 (PRT) was investigated. The nutrient solution-screening test with 148 mM Al concentration was used. A single gene pair controls tolerance to aluminium toxicity in these cultivars. It represents the same source of tolerance as that found in spring wheat BH-1146.

The resistance to leaf rust (Puccinia recondita f. sp. tritici) was evaluated for 29 genotypes of Triticum durum, including 16 cultivars of foreign origin and 13 home lines, in the years 1999–2000. Plants from each of the above-mentioned forms were inoculated at the seedling stage in a greenhouse with four pathotypes of leaf rust and under field conditions in the 8–9 stage according to the Feeke’s scale, with a mixture of the pathogen cultures. Twelve tested forms (7 cultivars and 5 lines) showed a very high resistance to leaf rust at the seedling and adult plant stages. Eight genotypes (5 cultivars and 3 lines) showed a moderate adult plant resistance.

The effects of sowing time, sowing density and nitrogen fertilization on grain yield and its components were tested for new spring wheat cultivars in a pot experiment conducted in the years 1999 and 2000. The investigated forms showed different requirements in regard to all the experimental factors.

The microplot experiment was conducted with the spring wheat cv. Sigma in the years 1989–1991. The aim of this research was to define changes in the crop canopy under the influence of sowing density and soils conditions. The results show that canopies consisted of plants with different number of tillers and different stem height. Deterioration of soil conditions caused decrease in frequency of high plants and increase of frequency of low plants.

F1 hybrids with sterilizing Triticum timopheevi cytoplasm showed intermediate grain yield in relation to parental forms. Seven hybrids out of thirty six exhibited heterosis effect in grain yield, in relation to better parental form, ranging from 10 to 21%. For a part of hybrids this effect was confirmed in the second year. Grain yield heterosis was significantly dependent on the heterosis of head number per plot and kernel number per head. Significant variation of general and specific combining ability of male sterile and male parental lines was found. Heterosis effect of the hybrid yield was determined by general and specific combining ability of parental forms. There was no significant difference of the heterosis effect in response to soil conditions and sowing density.

Differences between cultivars were evaluated in winter triticale (Dagro, Bolero, Ugo, Malno, Tewo, strain CZR 103/85) by comparing electrophoretic diagrams of gliadins. Percentage shares of particular gliadin subunits were used to prepare a scheme of diagrams for the studied triticale cultivars. On the basis of this scheme the relative diversity index was calculated for each pair of the compared cultivars. The values ranged from 20% to 70%. The indices may be useful in evaluation of degree of genetic differentiation between cultivars and for testing the effectiveness of planned crosses.

The effects of five variants of growth regulators and fungicide on yielding of winter triticale fertilized by increasing doses of nitrogen were investigated in two series of three years field experiment. A significant influence of the investigated factors as well as most of interactions on grain yield, plant height and lodging has been found in both series of the experiment. The results averaged for different combinations of growth regulators and fertilization revealed that the highest increase of grain yield (17.2% in series I, 15.4% in series II) and the most distinct growth regulator effect on length of stems and lodging were obtained in the variants BercemaCCC (3 l/ha) applied at the growth stage Fe 3 (according to Feekes scale) and Flordimex T (2 lha) applied at Fe 8. The retardant effect of growth regulators and fungicide was partially modified by weather conditions of a year of investigation. The positive effect of Bercema CCC (4 l/ha) applied with fungicide Benlate (0.5 kg/ha) was well evident only in the year when an epidemic occurrence of take-all was observed on winter triticale.

The research was conducted on 13 cultivars of winter triticale together with the Elena wheat and the Dańkowskie Złote rye for comparison. The following traits were analyzed: energy and capacity of grain germination, falling number and activity of a-amylase. The presented results concern the two-years research (years covered: 1999, 2000). The energy and capacity of grain germination (PN-79/R-65950) were tested in Petri dishes, 15 cm in diameter. 100 grains were sown on a wet filter paper of ph 6.0–7.5. The dishes were put into a thermostat with temperature 23°C. After 4 days the energy of germination was estimated, after 7 days — the capacity of germination for rye, and after 8 days - the capacity of germination for triticale and wheat. The tests were conducted in three replications and four times: in full maturity of grain, 8, 16 and 24 days after harvest. The aim was to determine a period of seed dormancy. Falling number (PN-ISO 3093: 1996) was tested by means of the Hagberg-Perten's method and the activity of a-amylase using the Varner's method.

The vigour of seeds put to induced sprouting in spikes was investigated for the cultivars of winter triticale: Bogo, Moreno, Vero, in the years 1998–2000. Using the

Grain yield and its components were investigated in spring triticale F1 and F2 hybrids and in their parental forms in two field microtrials in two locations differing in soil quality in 1999, and in one location in 2000. The hybrids were obtained as a result of two series of crosses conducted in a factorial design: of seven females with four males in 1999 and five females with three males in 2000. The heterosis effect and combining ability of parental forms were determined. Differences within parents, hybrids, and in the contrast of parents vs. hybrids were highly significant. The grain yield heterosis in F1 hybrids was frequent and high. For individual hybrids the better parent heterosis ranged from -1.4% to 53.6% and averaged 23.3% in 1999 and 15.4% in 2000. No heterosis was observed in the F2 generation. The heterosis of grain yield resulted from heterosis of the number of ears per plot, number of grains per ear and 1000 grain weight. It depended significantly on the general and the specific combining ability of parental forms.

The investigations were carried out on the grain of 4 winter and 3 spring triticale cultivars, coming from 3 locations, harvested in 1996–1998. It has been proved that triticale cultivars differ considerably as to the physical, chemical and milling features. Winter triticale is characterized by better 1000 kernel weight, test-weight and accuracy as compared with spring triticale. Total protein and ash content were higher in grain of spring triticale. The Presto and Vero cultivars showed by the best milling value.

The effects of sowing time, sowing density and nitrogen fertilization on grain yield and yield structure of new spring triticale cultivars were examined in experiments conducted in 1998–2000. The MAH 1898 and MAH 1998 cultivars utilized well high nitrogen fertilization, but MAH 2099 and MAH 2199 medium fertilization doses. All the cultivars tested in the experiments had similar requirements to sowing density — 400 grains per m2. MAH 1998 and MAH 2199 were less sensitive to sowing date, on the other hand the cultivars MAH 1898 and MAH 2099 gave higher yield when sown early.

The malting quality of spring barley was evaluated for the home-bred cultivars from ZD HAR BąkĂłw, ZD HAR Strzelce, SHR ModzurĂłw, HR Polanowice and HR „Piast” Łagiewnik in the years 1997–1999. Barley grain came from preliminary and pre-preliminary experiments performed in three locations each year. Coefficients of variability (CV%) and variability coefficients of phenotypic (CV (p)%) and genotypic (CV (g)%) variation were determined for 1000 grain mass, grain filling, total grain protein, and after micromalting, for percentage of total and soluble protein of the malt, Kolbach index, extractability, wort viscosity, diastatic power and final fermentation degree. The influence of interaction effect of objects with localities was highest for diastatic power. The heritability expressed was high for thousand-grain weight, malt fragility and diastatic power.

Three-years study on androgenesis in anther cultures of 11 cultivars and 5 F1 hybrids of spring barley demonstrated in different androgenesis ability of the investigated forms. The genotype dependent androgenesis ability and the genotype x medium interaction were confirmed. Four induction media (FHG0, FHG1, BAC4, BAC5) and two regeneration media (FHGR1, FHGR2) were applied. In the first year of study the following percentages of regenerated green plants were recorded for the genotypes: F116 — 5%, F1 471 — 5%, F1 463 — 1,2% and for the cultivar Haisa — 2%. The remaining genotypes regenerated into albino plants. Among the hybrid genotypes an influence of mother plant on androgenesis ability was observed. In the second year of study all the cultivars showed good androgenesis response (25% responding anthers), however regeneration of calli was poor: only 2 green plants was obtained from the cultivar Olga. In the third year 5 green plants from the cultivar Krona and 1 from the cultivar Olga were obtained. The result of androgenesis in the cultivar Haisa from the first year was not repeated — only albino plants regenerated. Furthermore, among the applied media the FHG0 and BAC5 proved to be more favorable than the FHG1 and BAC4 in androgenesis induction, whereas there were no differences in effect of the regeneration media FHGR1 and FHGR2.

In last years many new high yielding population and hybrid varieties appeared on the market. In the paper effects of rye breeding and their practical utilization were estimated. The estimation was conducted by the method of changing yield potential of varieties. In conditions of varietal tests, in the period 1986–2000, the average yields of rye increased by 26 kg/ha/year as an effect of breeding. Potential effects of plant breeding on seed production and in merchandise production on farms were 4.3 and 2.6 kg/ha respectively. Practical utilization of the plant breeding effects is even lower, additionally limited by a low level of agricultural technology on farms. One of the main reasons of unsatisfactory breeding impact on the production level is an increasing dissonance between the breeding effects and the level of supply with seed of new varieties.

In order to determine a supposed effect of different sources of cytoplasm inducing male sterility on the agronomic performance of rye hybrids, 3 three-way hybrids (genotypes), each in 4 cytoplasmic versions, were compared in field trials. Four sources of male sterility-inducing cytoplasm: cms-P, cms-R, cms-S and cms-C were used in the study. A two-factor split-plot field experiment was conducted in 6 environments (3 years, 2 locations). The sources of male sterility-inducing cytoplasm used in this study did not cause changes in the agronomic performance of hybrids. All of the cytoplasmic versions of hybrids, independently on genotype, resembled closely each other in respect of grain yield level, grain quality parameters and majority of the other evaluated agronomic traits. Although the hybrids with cms-P cytoplasm were shorter in height, had lower seed set per spike and produced grain having higher test weight in comparison to hybrids with cms-R, cms-S, and cms-C cytoplasm, the differences were small enough to consider them practically unimportant. The results showed that the use of cms-R, cms-S, cms-C or other similar source of male sterility-inducing cytoplasm, genetically different from Pampa (cms-P), for hybrid rye breeding purposes should not decrease an economic value of hybrids produced.

Nine rye cultivars, two strains and their progeny S1, S2 obtained after mass selection directed towards increased tolerance to N deficit were used in the study. The selection performed in hydroponic cultures was based on the morphological traits of 7-day seedlings developed for ten days on the medium containing 10.506 mg N/dm3. The control constituted seedlings grown on the Hoagland medium (168.0 mg N/dm3). Each rye population was represented 500 seedlings. The 35–37% of well-developed seedlings considered as tolerant to N deficit, were planted on the plots in the experimental fields. After sib-crossing the collected seeds constituted the initial material for the next cycle of mass selection. Initial material (S0) and S1, S2 populations were compared for their growth characteristics and electrophoretic patterns of storage proteins obtained by SDS-PAGE method.

The results are presented of studies concerning percentages of particular potato varieties in cultivation and in seed production. Regional differentiation was studied basing on the situation in two representative regions: mazowieckie and wielkopolskie. A low stability of the scattered seed market was stated, as well as a considerable differentiation of varietal structure in seed production when compared to that in production for use. The regional differentiation was evident in percentages of potato variety groups in the market. Implementation of the new policy by the varieties’ owners and introduction of the list of recommended varieties are expected to increase concentration of the varietal structure..

Field experiments were conducted in three vegetation periods in order to examine the effect of nitrogen fertilization (0 or 200 kg N · ha-1) on peroxidase and catalase activities in tubers of the potato cv. Uran. Activity of the enzymes was determined in three growth phases of the period from July (flowering) to September (harvest). The highest activity of peroxidase and the lowest of catalase were recorded at the flowering phase, independently on the nitrogen fertilization. Next, the activity of peroxidase decreased until harvest and that of catalase increased, reaching the maximum at the haulm drying up time. The effect of nitrogen fertilization on the increase of peroxidase and catalase activities was significant during a whole vegetation period. The difference was about 43%, in comparison to the non-fertilized tubers. The observed increase of these anti-oxidative enzymes activity could result from an oxidative stress caused by the excessive N-dose.

A two-factorial field experiment was conducted on loess soil in the Czesławice Experimental Station in 1997–1999, with the split-plot method with four replications. Two soybean cultivars: Aldana and Polan, and five methods of soil tillage were the experimental factors. The tillage treatments were following: I conventional, II reduced — without stubble operations, III reduced to cultivator, harrow and then subsoiler application, IV reduced with direct sowing of white mustard and harvest of the mustard in late autumn followed by deep moldboard plough, V reduced to direct sowing of white mustard, which was sprayed with Reglone (diquat) in spring and finally soybean was sown with the direct sowing method. The statistically elaborated results proved the same level of soybean yielding (1.72–1.84 t of seed ha-1) under all the tillage systems where plough was applied before winter (the systems I, II and IV). In comparison to the best treatments I and IV, the direct soybean sowing (V) caused a remarkable seed yield reduction (15% and 16%, accordingly). The Aldana cultivar’s yield (1.93 t ha-1) was almost 28% higher than that of the Polan cultivar (1.51 t ha-1). Generally, field emergence of soybean was low (mean about 46% of the assumed).

Evaluation of agronomic effect of the use of new type hillers on potato cultivation was the aim of the experiments performed in the Plant Breeding and Acclimatization Institute Branch Division Bonin, on a medium-heavy soil, in 1997-1999. The research referred to determination of an influence of different types of hillers on ridges formation, soil compactness, yield, its structure, quality and tubers arrangement in a ridge profile. The highest potato yields were obtained after the use of the hillers with devices to ridge formation. The differences in yield were proved statistically. The influence of the cultivation method on tuber quality was also significant. The mass of greened tubers or tubers infected by late blight was reduced over three times on the plots cultivated with the hillers P 500 or UFO 97.