Volume 23 (2011): Issue 1 (June 2011)

The characteristic growth features of four Welsh onion cultivars (‘Parade’, ‘Performer’, ‘Siedmiolatka Zielona’, and ‘Siedmiolatka Czerwona’) dependant on growing method (seeds sown directly in the field and from transplants) were evaluated during the three-year study (2007-2009). The following traits were determined: plant height, number of leaves on a single plant, tendency to produce laterals, plant weight, as well as length and diameter of the pseudostem. Plants of the ‘Parade’ cultivar were the highest (76.0 cm, on average), while those of ‘Siedmiolatka Czerwona’ were the shortest (mean 68.6 cm). Pseudostem length was found to be the main factor determining the height of the Welsh onion. The longest pseudostems were observed for the ‘Parade’ and ‘Performer’ cultivars, while the ‘Siedmiolatka Czerwona’ had the shortest.

In each of the tested cultivars, those grown from a transplant resulted in larger pseudostems and a larger number of leaves. Amongst the studied cultivars, ‘Siedmiolatka Czerwona’ had the most numerous leaves and laterals (45.2 leaves and 14.3 laterals, on average), while ‘Performer’ and ‘Parade’ had the least (mean 11.7 and 14.8 leaves and 2.4 and 2.6 laterals, respectively). The weight of a single plant with laterals significantly differed depending on the cultivar and growing method. At the end of the vegetation period (mid-October), the ‘Parade’ and ‘Performer’ cultivars grown from transplants were characterised by the highest weights (mean 518.2 g and 631.7 g), while ‘Siedmiolatka Czerwona’ and ‘Siedmiolatka Zielona’ grown from seeds had the lowest (222 g, on average).

This study investigated the effect of foliar feeding with Florovit and Ekolist-Warzywa + urea liquid fertilisers on yield quality and the content of selected nutritive value components of three medium-fruit melon cultivars (‘Charentais F₁’, ‘Melba’, and ‘Fiesta’). A higher total yield was harvested from plants foliar-fed with Florovit and Ekolist-Warzywa + urea compared with the control without foliar feeding. The ‘Fiesta’ cultivar was characterised by the highest total yield. The type of foliar feeding significantly affected the total number of fruit per square metre. More fruit per metre squared was produced by Florovit-fed plants in comparison to Ekolist-Warzywa + urea. ‘Charentais F₁’ produced the greatest number of fruit. ‘Fiesta’ had the highest proportion of marketable fruit. The factors investigated did not have any influence on the percentage of disease-affected and unripe fruit. The greatest amount of dry matter and ascorbic acid were determined in the fruit harvested from the control and plants foliar-fed with Ekolist-Warzywa + urea, respectively. The highest levels of both components were assayed in ‘Fiesta’. Regardless of the type of foliar feeding, ‘Fiesta’ and ‘Charentais F₁’ produced the highest quantity of total sugars and monosaccharaides as compared with ‘Melba’.

Three cultivars of Hyacinthus orientalis L. were forced under artificial light using fluorescent lamps emitting white, blue, green, yellow and red light. Quantum irradiance was determined as 12.5 and 25 μmol m^-2 s^-1. Day length was 12 and six hours, respectively. Daily light integral was 0.54 mol m^-2. A significant effect of light colour on flowering date and plant quality was observed. Plants forced in blue and red light were the first to flower. Plants exposed to red light formed longer inflorescences. Plants forced under lamps emitting blue light formed shorter, more rigid flower shoots with shorter leaves.

There were no significant differences between plants grown under 25 μmol m^-2 s^-1 of quantum irradiance for six hours per day and plants grown under light with a quantum irradiance of 12.5 μmol m^-2 s^-1 for 12 hours per day. This means that the light-dosing variant did not exert any effect on the growth and flowering of hyacinths.

In 2007-2008 the effects of pot marigold (Calendula officinalis L.) and cypress spurge (Euphorbia cyparissias L.) water extracts on the occurrence of pest insects on white cabbage were tested. The numbers of cabbage aphid (Brevicoryne brassicae L.) were significantly lower on the treated plants. During the period of the most numerous occurrence of aphids on the unsprayed plants, their number was almost twice as high as on the plants sprayed with spurge extract and almost three times as high as on the plants sprayed with marigold extracts. Spraying plants had an effect on the number of Phyllotreta atra and P. nemorum beetles and Pieris rapae L. eggs. Pot marigold extract proved to be the most effective in this respect. Egg clusters of large white butterfly (P. brassicae L.) and cabbage moth (Mamestra brassicae L.) were observed only in 2008, and only on the control. In the case of the diamondback moth, Plutella xylostella L., only marigold extract had a positive impact on reducing its number. Diamondback moth larvae numbers were even slightly higher on plants treated with cypress spurge extract than on the control plots where plants had not been sprayed.

Zucchini is a very valuable vegetable, easy to grow both in the field and under covering, but it is affected by pathogenic fungi. The experiment was carried out at a farm near Lublin where three zucchini cultivars, ‘Astra Polka’, ‘Atena Polka F₁’ and ‘Soraya’, were cultivated in a plastic tunnel and in the field in 2008-2009. The leaves, petioles and stems of zucchini were collected for laboratory tests. Mycological analysis showed that the predominating fungi were Alternaria alternata, Fusarium spp. and Rhizoctonia solani. Fusarium spp. were isolated in the greatest numbers from zucchini plants cultivated in the field. R. solani was isolated in greater numbers from zucchini cultivated in a plastic tunnel as compared to the field.

During the sampling period, 243 syrphid larvae belonging to seven species were collected from M. cerasi colonies on P. avium. Episyrphus balteatus Deg. and Epistrophe eligans (Harr.) were the most numerous species amongst the materials gathered, followed by Syrphus ribesii (L.) and S. vitripennis Meig. All of these species play an essential role in reducing M. cerasi populations. Amongst the Coccinellidae occurring in black cherry aphid colonies, Adalia bipunctata L. was the dominant species, while the subdominant was Coccinella septempunctata L. and Propylaea quatuordecimpunctata (L.).

In 2003 and 2004, young ‘Kordia’ sweet cherry trees were sprayed with prohexadione-Ca (Pro-Ca) to control tree growth and stimulate flower bud setting. A rate of 200 mg Pro-Ca l^-1 × 2 dissolved in various pH-buffered (6.0-4.5) aqueous solutions was used. Regardless of the acidity of the spray solution applied, the trees treated with Pro-Ca were characterised by reduced shoot and internode length, greater number of shoots (2003) and increased total shoot extension (2004) relative to the control. In both years, Pro-Ca applied in a pH-4.5 buffer solution contributed to an increase of flower bud clusters on current-season shoots. However, there were no significant differences among Pro-Ca/pH treatments either in the vegetative or generative characteristics studied. Two years after Pro-Ca application, no residual effects were found in the studied tree characteristics.

In the period 2006-2008 a comparative study was carried out on the ‘Tempranillo’, ‘Syrah 99’ and ‘Syrah 100’ cultivars, grown in two microregions in Southern Bulgaria - Brestnik and Pesnopoy. The soils in the region of Pesnopoy are of a better mechanical and chemical composition, which preconditions the formation of relatively high yields of good quality grapes. The ‘Tempranillo’ cultivar was highly productive in both microregions, however the quality of the wines was lower, compared to the ‘Syrah’ cultivar. They were poorer both in the content of extract and in fruit aroma. ‘Syrah 99’ from Brestnik and ‘Syrah 100’ clones from Pesnopoy do not differ significantly in productivity, but the wines of ‘Syrah 100’ from the Pesnopoy region were more intense in colour and their aroma was strong, full-bodied and lasting with dominating floral (violet) and forest fruit nuances. Tasting results showed high scores, which is evidence that the young wines have potential and contain the ingredients and components necessary to develop further into top quality red wines.

In the experiment carried out in the Experimental Station belonging to the Wrocław University of Environmental and Life Sciences in 2004-2006, we estimated the effect of the type of the nitrogen fertiliser (ammonium nitrate, calcium nitrate, ammonium sulfate, urea and ENTEC 26) applied as preplant (150 kg N ha^-1) or split dose (100 + 50 kg N ha^-1) on the yield and dry matter content, nitrates, vitamin C and P, K, Mg, Ca in ‘Optiko’ Chinese cabbage cultivated during the spring season. The highest total and marketable yield of Chinese cabbage was recorded after the use of urea, which was partly associated with the lowest percentage of diseased heads. Plants fertilised with ammonium sulfate provided the lowest yield. The method of nitrogen application significantly affected the yield and the mean weight of individual heads in the marketable yield, but not the accumulation of nitrates and vitamin C. The lowest accumulation of nitrates was associated with the use of ammonium sulfate and ENTEC 26, whereas the highest with urea. The use of calcium nitrate at a single dose of 150 kg N ha^-1 led to the highest accumulation of vitamin C in Chinese cabbage leaves. The levels of P, K, Mg and Ca showed only small changes and were not significantly affected by the type of nitrogen fertiliser or the method of its application.

Two field experiments with leaf lettuce were conducted in 2006-2008. The first factor tested was the diversified contents of mineral nitrogen in the soil, amounting to 50, 100 and 150 mg N dm^-3 before lettuce cultivation. The second factor tested four nitrogen fertilisers differing in chemical composition and in nitrogen form introduced into the soil: ammonium nitrate 34% N - (NH⁴NO³), calcium nitrate 15.5% N - (Ca(NO³)² × H²O + NH⁴NO³), ammonium sulfate 20.0% N - ((NH⁴)²SO⁴), and ENTEC 26% N - (NH⁴NO³ + (NH⁴)²SO⁴ + 0.8% DNPP). Two cultivars of leaf lettuce were used: green leaf ‘Casabella’ (Lollo Bionda type) and red leaf ‘Klausia’ (Lollo Rosa type). The best source of nitrogen for ‘Casabella’ cultivar lettuce was ENTEC 26 fertiliser and calcium nitrate, which resulted in significantly higher yields as compared to ammonium sulfate, yet did not differ from the yields comprising plants fertilised with ammonium nitrate. In the case of the ‘Klausia’ cultivar, ENTEC 26 fertiliser and ammonium nitrate generated the best production results. Regardless the type of nitrogen fertiliser used, the increase in concentration of this element in soil from 50 mg N dm^-3 to 150 mg N dm^-3 resulted in a considerable increase in marketable yield of both cultivars with simultaneously higher nitrate accumulation and decreased dry matter in the ‘Klausia’ cultivar. Lettuce fertilised with ammonium sulfate as well as with ENTEC 26 presented significantly lower average nitrate content in leaves before harvesting than after application of ammonium and calcium nitrate as a source of nitrogen for the plants. Introduction of ammonium nitrate and calcium nitrate in the dose of 150 mg N dm^-3 contributed to nitrate accumulation in the amounts exceeding permissible by legal regulations regarding the content of this element in lettuce, while application of ENTEC 26 allowed us to obtain a high yield size of both lettuce cultivars without risk of exceeding permissible nitrate content.

The objective of the experiment was to compare mycelium growth and the yield of wild strains of Pleurotus ostreatus derived from natural sites and of a cultivated HK35 strain. Mycelium growth was investigated on substrates prepared from the sawdust of deciduous trees, wheat and rye straw as well as by-products from the textile industry: flax and hemp shives. Irrespective of the applied substrate, the cultivated HK35 strain was characterised by the fastest growth, whereas amongst the examined wild strains, mycelia designated as U18/5, S12/3 and B17/4 were found to grow best. Substrates prepared from wheat and rye straw and flax shives turned out to be the best for mycelium growth of the tested strains of P. ostreatus. The yield of oyster mushroom depended on the type of applied substrate. Higher yields were recorded on substrates from flax shives and a mixture of wheat straw and hemp shives than on wheat straw. The cultivated HK35 strain and the wild S12/3 strain gave the highest yields irrespective of the kind of substrate.

Field studies were conducted in the years 2003-2005 in the Experimental Farm of the University of Life Sciences in Lublin. Beans from four cultivars - ‘Paulista’ and ‘Hit’ (green pods) and ‘Korona’ and ‘Galopka’ (yellow pods) - were grown on fawn soil, formed of loess deposits, on chalky marls, containing 1.4% organic substances on average. There were six sowing terms, every 6-7 days starting from the middle of May to the end of June. French bean harvest was performed once, when about 75% of the pods on the plants were in the phase of technological maturity, which fell between the third ten days of July and the first ten days of September. From the plot and plant the number and yield of the pods were determined: total, marketable and non-marketable small pods, unshapely and overripe pods, as well as those with symptoms of disease. The highest total and marketable pod yields - on average, 15.45 and 11.06 t ha^-1, respectively - were obtained from plants sown in the first ten days of June, whereas the lowest - 12.54 and 9.54 t ha^-1 - were from those sown in the middle of May. As a result of performing a one-time French bean pod harvest, the share of non-marketable pod yield in the total yield was on a similar level (24-28%), depending on the growing term. Variability was demonstrated in the share of particular non-marketable yield fractions (small pods, undersized, unshapely, and overripe pods, as well as those with disease symptoms), depending on the sowing date. Growing four French bean cultivars from sowing in the period from the middle of May to the end of June allowed us to extend the period of fresh pod harvest to six or seven weeks.

The aim of the present study was to evaluate the effect of short-term high or low temperature treatments applied during seed imbibition on plant tolerance to chilling. Chilling tolerance was also investigated on seedlings obtained from dry seeds stored at low temperatures. Sunflower seeds (Helianthus annuus L. ‘Wielkopolski’) were stored at 5°C or 25°C and then subjected to low (2.5°C and 5°C) or high (35°C and 45°C) temperatures for two hours during imbibition. They were subsequently exposed to chilling (2.5°C) for three weeks. Afterwards, the seeds were transferred to 25°C for chilling injury evaluation or sown in pots and grown in the field for further growth investigation.

The obtained results indicate that the sunflower seedlings, obtained from dry seeds stored at 25°C, were chilling sensitive to an exposure of 2.5°C for three weeks, which was manifested by slow root elongation, external root discoloration and a long Mean Emergence Time (MET). The storage of dry seeds at 5°C reduced seedling injuries exhibited by external root discoloration and increased chlorophyll content in leaves. Short-term (two-hour) low (2.5 and 5°C) or high (35 and 40°C) temperature treatments applied to the moistened seeds alleviated chilling effects, stimulating root elongation, limiting external root discoloration and shortening MET, accelerating plant flowering and seed maturation time, increasing the diameter and weight of the anthocarp as well as seed yield and chlorophyll content.

The positive response of these methods in respect to an increase in sunflower plant tolerance to chilling indicates a possibility of their application in practice.