Volume 23 (2011): Issue 2 (December 2011)

The aim of the research was the analysis of 11 DH-R₂ pepper (Capsicum annuum L.) lines, obtained in anther cultures of ‘(ATZ1 × PO)’ F₁, ‘(ATZ1 × CDT)’ F₁ and ‘(ATZ1 × TG)’ F₁ hybrids. To determine the genetic homogeneity of anther-derived lines, the biometrical characteristics of fruits, as well as fruit colour and shape inheritance, were analysed. The biometrical analysis determined the highest phenotype uniformity in androgenic lines of ‘(ATZ1 × PO)’ F₁. Based on the fruit shape and colour variation, it was possible to determine the microspore origin of androgenic diploids obtained in anther cultures of ‘(ATZ1 × TG)’ F₁. Additionally, enzyme analysis of four isozymes (PGM, PGI, IDH and MDH) showed that isocitrate dehydrogenase identified anther-derived diploids of hybrids between ‘ATZ1’ and ‘TG’, as well as those between ‘ATZ1’ and ‘CDT’, lines.

In 2006-2008, yielding was determined and biometric measurement as well as chemical analysis was carried out for five Lithuanian sweet cherry cultivars, ‘Agila’, ‘Seda’, ‘Vasare’, ‘Ventenue’, and ‘Jurgita’, and two cultivars commonly grown in Poland, ‘Ulster’ and ‘Burlat’. Trees grafted on Mazzard seedlings were planted in 2002 in the orchard of the Pozorty Experimental and Production Institute in the village of Łęgajny near Olsztyn. The highest mean yield for the tested cultivars was obtained in 2008, while the lowest was in 2007, when the highest ground frosts were recorded during the cherry blossoming period. During the three years of research, the highest mean yield for the Lithuanian sweet cherry cultivars was established for the ‘Vasare’ cultivar, which together with the ‘Burlat’ cultivar made a homogenous group of the highest values. The mean fruit weight of the Lithuanian cultivars was lower than in the case of ‘Burlat’ and ‘Ulster’, while the largest fruit amongst the Lithuanian cultivars were recorded for ‘Jurgita’ and ‘Agila’. The chemical composition analysis of fruit revealed significant differences both between the cultivars and the years of the research. The fruits of the studied cultivars accumulated the lowest amounts of total saccharides and vitamin C in the coolest year under analysis, 2007. The highest mean of total saccharide content was recorded for fruit of the ‘Vasare’ and ‘Seda’ cultivars. Fruit of the ‘Agila’ cultivar accumulated the highest amounts of organic acids and vitamin C.

Two green kohlrabi cultivars, ‘White Delikates’ and ‘Korist’ F₁, were kept in cold storage at a temperature of 2°C and a relative humidity of 95%. Natural mass losses were measured at monthly intervals and dry matter content, soluble sugars, L-ascorbic acid and isothiocyanates were analysed. During five months of storage, very low losses of kohlrabi mass were detected. The decrease in dry matter during that time was between 15 and 18%. After a brief increase, soluble sugar content decreased during storage, and in March, 50% of the initial sugar content was calculated for ‘Delikates’ kohlrabi flesh and 65% for ‘Korist’. L-ascorbic acid was well preserved in the kohlrabi, since 90% remained after storage was completed. The isothiocyanate content changed little and the vegetable remained a good source of these compounds throughout the storage period.

A field experiment was carried out in the years 2007-2009 at the Research Development Station of the Department of Horticulture at the Wrocław University of Environmental and Life Sciences. The experiment involved two botanical varieties of endive: var. latifolium (nine cultivars) and var. crispum (five cultivars). Endive was cultivated from transplants produced in a greenhouse in two terms, for spring and autumn harvesting. The harvest took place 90-100 days after the seeds were sown. In the course of harvesting, the total and marketable yields were determined, while biological value was assessed on the basis of analyses regarding the content of dry matter, vitamin C, chlorophyll and carotenoids, as well as the amounts of such elements as Mg, P, K, Ca and nitrates.

‘Melodion’ butter lettuce was grown on rockwool slabs in a film tunnel in the spring and summer-autumn seasons. The following experimental factors were investigated: foliar application with a solution of urea (1%), Mo (1 mg dm^-3) and benzyladenine (5 mg BA dm^-3) and light conditions in the film tunnel (films covering two parts of the tunnel differed in light permeability for PAR radiation). The nitrate metabolism was studied before application, three days after treatment and on the harvest day (seven days after application). Higher light intensity stimulated nitrate reductase activity, ammonium ions and soluble sugars, while fewer nitrates were observed in lettuce leaves. In the spring season, the least nitrate ions occurred as a consequence of urea + Mo nutrition, and when BA was added in the summer-autumn. Moreover, a positive effect on soluble sugar content was also observed when BA was used. In the spring, BA stimulated nitrate and nitrite reductase activities in the leaves of lettuce that had received less light.

The aim of this study was an attempt to determine the influence of PGRs - auxins, cytokinins and gibberellic acid - on the flowering and morphogenesis of ‘Flash Red’ Petunia × atkinsiana D. Don in vitro. The best results at the propagation stage were obtained on an MS medium supplemented with 0.5 mg dm^-3 GA₃. The petunia plants propagated under these conditions developed high main shoots and a large number of leaves and adventitious shoots. The plants with the best-developed root system were regenerated on an MS medium supplemented with 0.5 and 1.0 mg dm^-3 IAA. Flowering initiation should be performed using an MS medium supplemented with 0.5 mg dm^-3 KIN.

The aim of the research, which was carried out in the years 2003-2005, was to assess the possibility of creating regression models for the earliness of Chinese cabbage (Brassica rapa var. chinensis, pak choy) plants cultivated under field conditions during the summer-autumn months. Four variables were chosen for developing the prediction model: the minimum, mean and maximum air temperatures and sunshine hours. After stepwise regression analysis, it was noted that crop earliness could be described as a function of mean air temperature and sunshine hours. For this model, the coefficient of determination R² was equal to 0.962. Additional models based on various thermal indices - growing degree days (GDD), heliothermal units (HTU) and photothermal units (PTU) - were also constructed and taken into consideration. The linear regression equation that includes GDD could only simulate the earliness of the plants with a precision below 14%. The model built on the basis of PTU showed a better fit of the predicted data to the observed data (around 49%), while the last model, which incorporated HTU, was the most accurate (R² was equal to 0.843). Models for the growth of pak choy plants in the field based on a time variable are also presented in this paper.

The objective of the presented experiment was the showing of the possibility of replacing daminozide, contained in the preparation B-Nine 85 SP, by metconazole, contained in Caramba 60 SL preparation, in pot cultivation of pot chrysanthemum ‘Leticia Time Yellow’. Experiment was carried out in three cycles: in the spring, beginning 10 April; in the summer, beginning 11 June; and in the autumn, beginning 13 August, 2007. The metconazole contained in the Caramba 60 SL preparation was able to impede the growth of ‘Leticia Time Yellow’ chrysanthemum as effectively as the daminozide contained in the B-Nine 85 SP preparation. However, the effectiveness of metconazole depended on its concentration and on the dose of the preparation, on the number of treatments and on the growing term in the plastic tunnel. In the summer term of cultivation, the effect of metconazole applied only once in a concentration of 300 mg dm^-3 was comparable with the effectiveness of daminozide applied twice in a concentration of 2,550 mg dm^-3, and in the autumn cultivation, the effectiveness was even higher. In addition, no retardation of flowering was recorded, either in relation to the plants sprayed with daminozide or in relation to the control plants not sprayed with any retardant.

The experiment was conducted using five species of roses naturally occurring in Poland: Rosa agrestis (fieldbriar rose), R. canina (dog rose), R. dumalis (glaucous dog rose), R. rubiginosa (sweetbriar rose), and R. tomentosa (whitewooly rose), from the in vitro collection of the Department of Ornamental Plants of the University of Agriculture in Kraków. We examined the effect of cytokinin BA (1-10 μM) added to an MS medium (Murashige and Skoog 1962) on auxiliary shoot multiplication. The second group of test media contained BA (1-5 μM) and gibberellin GA₃ (0.3-1.5 μM). The cultures were maintained at a phytotron temperature of 23/25°C (night/day), 80% relative humidity, with a 16-hour photoperiod and PPFD of 30 μmol m^-2 s^-1, and cultured in five-week cycles. The highest multiplication rate was obtained for R. canina and R. rubiginosa (4.1 shoots per one explant) and R. dumalis (2.9 shoots per one explant), when shoots were multiplied on an MS medium supplemented with 1 μM BA and 1.5 μM GA₃. Multiplication was the weakest in Rosa tomentosa independent of the medium used.

A field experiment was carried out in 2006-2008. The study examined the effect of soil mulching with synthetic materials (black polyethylene film, black polypropylene nonwoven 50 g m^-2, and black polypropylene fabric 94 g m^-2) on the fruit yield and quality of two melon cultivars (‘Seledyn’ and ‘Yupi’) grown in the field under the climatic conditions of central-eastern Poland. Specimens grown without mulching served as the control. The climatic conditions during the study years had a significant influence on the level of total, marketable and early yield of melon. The highest melon yield was obtained in 2007, which was characterised by the most favourable weather conditions for melon cultivation. The comparison of the cultivars showed that ‘Seledyn’ was better adapted to the climatic conditions of Poland. From cultivation, this cultivar achieved significantly higher early and total fruit yield compared with ‘Yupi’. ‘Seledyn’ was also characterised by a higher share of early yield of the total yield, a higher number of fruit in the early yield and a higher mean fruit weight. In turn, ‘Yupi’ produced a significantly higher share of marketable yield of the total yield and a higher number of marketable fruit.

Research was carried out on the effect of the umbel position on the ‘Amat’ dill (Anethum graveolens L.) plant on selected features of the seed stalk in the years 2002-2004. Commercial seeds of the species were sown on a small production field and grown for the purpose of producing seeds. Out of the field plant stands, three hundred plants were randomly selected. The following morphological features were then measured in respect to the seed stalk architecture in these plants: the length of the seed stalk, number of branches with primary, secondary and tertiary umbels, length of branches with primary umbels, as well as the main and primary umbel diameters. In addition, seed yield per plant, the weight of 1000 seeds, germination capacity, seed length and width, seed embryo and endosperm lengths for seeds from the main and primary umbels were also calculated and measured. Additionally, the main and primary umbels were divided into three parts: external, middle and internal, and seeds from each were examined separately. The position of the umbel on the seed stalk did not affect the number of branches with primary, secondary, and tertiary umbels on the dill plant and had no effect on its seed stalk architecture. There was no significant difference within the position of the main and primary umbels on the seed stalk grown in field stands. The diameter of the main umbel was the same as the primary one. The lower its position on the seed stalk, the lower the seed yield and germination capacity. The best seeds, in terms of their 1000 seed weight, came from the external part of the main umbel. The different localisation of seeds within the three designated parts of the main umbel had no effect on seed length or width or on their endosperm and embryo lengths. The recorded seed embryo length from the internal part of the primary umbel was smaller than its values from the two other parts of that umbel.

The aim of the research conducted in 2007-2009 was the evaluation of the pathogenicity of eight Plasmodiophora brassicae Wor. isolates collected from clubroot-infested white cabbage growing in different areas of Poland. Breeding materials from white cabbage resistant and susceptible to P. brassicae were used for this purpose. Cabbage seeds were infected by submerging them into a spore suspension. The screening of plant clubroot resistance using a nine-degree scale based on root symptoms was carried out at the eight-week-old seedling stage and at harvest time on a field infected by P. brassicae spores - called the ‘death field’. Differences in the pathogenicity of the collected isolates were determined. Isolates from Szczecin, Ostromęczyn, Krojczyn and Maszkienice were defined as the most virulent. Plants of the ‘Kilaxy’ F₁ white cabbage cultivar confirmed resistance to all isolates, while plants of the susceptible HTM line from the ‘Hitoma’ F₁ white cabbage cultivar were characterised by the highest infestation level. The evaluation of adult plants in the field with high P. brassicae spore contamination confirmed seedling test results. Different susceptibility was observed between sub-lines from the ‘Oregon 123’ and ‘Badger Shipper’ cultivars with resistant genes. ‘Oregon 123’ sub-lines were less susceptible to applied isolates than ‘Badger Shipper’ sub-lines at both the seedling stage and during the field test. A double-stage plant screening to pathogen reaction caused the elimination of the most susceptible plants at the seedling stage. Plants with a certain resistance level were planted in the ‘death field’.