Volume 24 (2012): Issue 2 (December 2012)

A two-year-greenhouse experiment was designed to investigate the effect of four chelates, differing in percentage of Fe content and the kind of Fe bonding ligand: Fe 8 Forte (EDTA+HEEDTA), Fe 9 Premium (DTPA), Fe 13 Top (EDTA) and Librel Fe DP7 (DTPA), on the yield and fruit quality of the ‘Merkury’ F₁ greenhouse tomato cultivar grown in peat substrate. Each of the tested fertilisers was applied in three different doses in order to reach the level of 50, 75 or 100 mg available Fe per 1 dm^-3 of growing medium. In the control treatment the amount of this nutrient was equal to 17.9 mg dm^-3. The tomato was cultivated from transplants on benches in the period from the beginning of April to the end of July.

The highest marketable yield of tomato fruits was obtained from plants fertilised with Fe 9 Premium (DTPA), while the lowest was from the treatment with Fe 13 Top (EDTA) chelate. Both of these sources of iron were equally efficient for the early crop yield, which was significantly higher than that of other tested fertilisers. Irrespective of the Fe source, the most favourable dose of this nutrient for marketable and early fruit yield was 50 mg Fe dm^-3. Both tested factors had little effect on fruit composition. The only exception was a significant drop of vitamin C content in the treatment supplied with Fe 9 Premium and an increment of Na in the case of Fe 13 Top use. The increase of Fe in the growing medium up to 75 and 100 mg dm^-3 adversely affected the amount of P in tomato fruits.

The purpose of this research was to investigate the combining ability of inbred lines in terms of traits important for the development of hybrid carrot cultivars with high yields and better root quality. The experimental plant material consisted of 15 inbred lines that were crossed in an incomplete diallel design to produce 34 hybrids. It was observed that the variation of general combining ability (GCA), specific combining ability (SCA) and reciprocal effects (RE) were significant for all of the tested characters, except SCA for sugars. Among the tested lines, the RFO had the most positive GCA for the yield; at the some time, the RFO line had negative GCA for carotenes and dry matter content. A significant positive GCA was found for all traits, except monosaccharides and nitrates, for the 2163 line. Most of the crosses based on the RFO and 2163 lines yielded well; additionally, the hybrids based on 2163 presented high levels of quality characters. The ratio of GCA:SCA indicated that the quality traits were mainly affected by additive gene effects, but the yield was controlled more by non-additive gene effects. Heritability in a broad sense presented a higher environmental influence for yield than the quality characters of carrot roots.

The experiment investigated the effect of different irrigation methods (no irrigation, irrigation by means of a drip tape) and method of AgroHydroGel application (control, AgroHydroGel applied to seedlings, AgroHydroGel applied to plants in the field, half of the AgroHydroGel applied to seedlings, the other half to plants in the field) on the yield level and quality of celeriac grown in the field. Irrigation significantly increased yields as well as the average weight of the marketable root; however, it had no influence on the nutrient contents. The application of AgroHydroGel to plants in the field or in a split proportion resulted in the most favourable influence on yielding. In the non-irrigated combination, AgroHydroGel applied entirely to plants in the field or in a split proportion increased marketable root yields. In the irrigated treatments, the highest yield was obtained in the plots where hydrogel was applied to plants in the field. Roots from the treatments where AgroHydroGel had been applied in a split proportion contained more dry matter as compared to the control. In the non-irrigated combination, AgroHydroGel applied entirely to plants in the field and in a split proportion increased ascorbic acid content. Simultaneously, irrigation and hydrogel application in a split proportion increased total sugar content as compared to the plants in which the hydrogel was only applied to the seedlings

The aim of this study was to introduce older transplants of broccoli into field conditions to shorten their growing period and to obtain a crop with a high nutritive value. The additional storage of relatively old (four- and eightweek- old) transplants in a cold chamber before planting in the field shortens the growing period; however, it can influence the chemical composition of the leaves and heads. According to earlier research, the preliminary chilling of transplants affected the high yielding of broccoli; a determination of the quality of plants, including select health-promoting properties, was necessary for their full characteristics.

In the present work, the four- and eight-week-old broccoli transplants were kept at 2°C either for one or two weeks before planting in the field. Catalase (CAT) and peroxidase (POD) activity as well and the accumulation of phenolic compounds were determined in the leaves of the transplants before and after chilling. The same parameters were detected in the leaves and heads of broccoli at harvest time. The effect of low temperature treatment on CAT activity was observed only at the stage of transplants; however, the increased activity of POD stimulated by chilling was maintained during the growing period until the harvest. The reaction of the plants to low temperatures can be connected with their mechanism against stress conditions and seems to vary in the case of those antioxidative enzymes. The effect of chilling on the accumulation of phenolics (total, cinnamic acid derivatives, flavonols) was noted only in transplants and was not evident during the harvest.

The differences observed between the individual seasons of the experiment, both in enzyme activity and synthesis of phenolics, were most likely caused by the differing climatic conditions

One of the key factors determining the effectiveness of pepper anther cultures is donor plant genotype. The stock material for androgenic embryos inductions is usually made up of hybrid forms, since the higher the degree of heterozygosity, the greater the chances of producing regenerates with unique genotypes. The aim of the presented research was to evaluate individual plant reaction in anther cultures for the C. annuum hybrid (‘ATZ1’ × ‘TG’)F2, interspecific hybrid (C. frutescens × C. chinense)F2 and androgenic DH line AT6. The effectiveness of androgenesis was determined individually for each plant as the percentage of the embryos produced compared to the total number of anthers cultured. In the hybrid (‘ATZ1’ × ‘TG’)F2, anthers of 19 out of 20 plants evaluated produced embryos at a rate of 0.5 to 16.5%. Anthers of the AT6 DH line formed embryos considerably less frequently. A positive reaction was recorded for 13 out of 20 plants and the effectiveness of androgenesis did not exceed 3% for this genotype. The lowest androgenic response was recorded for the hybrid (C. frutescens × C. chinense)F2, where embryo development was observed in only five out of 19 plants and the effectiveness of androgenesis did not exceed 2%. The ploidy level of the regenerates was defined cytometrically. The analysis revealed the presence of haploid and diploid plants among the regenerates of all the genotypes evaluated.

One-year-old Malus domestica Borkh. ‘Boskoop’ and ‘Mutsu’ nursery trees on M.9 rootstock were treated with foliar sprays of different BA + GA3 mixtures (450 + 450 mg dm-3 or 780 + 120 mg dm-3) or BA + GA4+7 combinations (450 + 450 or 330 + 570 mg dm-3). Both cultivars showed strong apical dominance; however, increased branching potential was observed following the use of exogenous growth regulators. All of the investigated branching agents revealed a high effectiveness, yet only after one treatment. Environmental factors played a major role in the induction of sylleptic shoot formation, especially in the case of ‘Boskoop’. In the case of ‘Boskoop’, the branching effect was correlated with several vegetative growth properties (tree height, trunk diameter), while for ‘Mutsu’, a different branching pattern was found with no correlations ascertained. No tree injuries were observed following the use of a chemical branching agent.

The ‘Spartacus’ F1 sweet pepper was grown in a plastic tunnel on rockwool during 2006-2008. A fertigation technique was used for water and fertiliser application. The tunnel was divided into two parts covered with different plastic films. The first part of the tunnel was covered with a film that transmitted less light than the film covering the second part. In both parts of the tunnel, the plants were divided into two groups. One group of plants was fertilised with just nitrate nitrogen (100% N-NO3) and the other one with three forms of nitrogen (N-NO3:N-NH4:N-NH2 in a ratio of 50:13:37). Fruits were harvested mature green and red. Concentrations of nitrate and ammonium ions as well as total nitrogen and free amino acids were analysed in the plant material. Nitrate and nitrite reductase activities were also investigated, and dry matter content and soluble sugars were also determined. Higher light intensity increased nitrate concentration in red pepper fruits but decreased ammonium ion content. These tendencies were not as obvious in green fruits. In most cases, red fruits fertilised with three nitrogen forms accumulated more nitrates than those fertilised with N-NO3. This observation was similar in the case of green fruits. In most cases, pepper fruits accumulated more ammonium ions in the case of N-NO3 fertilisation than when three forms of nitrogen were applied, but the differences were not always statistically significant. Higher nitrate reductase activity was observed in the case of better light conditions as well as mixed nitrogen fertilisation in red pepper fruits. No differences were observed in the case of nitrite reductase activity between fruits harvested from various treatments in red and also green fruits, with some exceptions. The green fruits of pepper had higher nitrate reductase activity than the red ones. It can be summarised that various light conditions influenced the nitrogen metabolism of pepper fruits as well as the different nitrogen forms applied with fertilisers.

Field experiments using ‘melt-blown’ biodegradable nonwovens were carried out on the ‘Melodion’ butterhead lettuce (Lactuca sativa var. capitata L.) cultivar for early harvest. All biodegradable nonwovens were manufactured in the Institute of Biopolymers and Chemical Fibres and POLMATEX CENARO in Łódź, Poland. Lettuce seeds were sown into boxes in a greenhouse at the beginning of March, and transplants were planted into the field at the beginning of April. Biodegradable nonwovens - aromatic polyester IBWCH 75 g m-2, polybutylene succinate Bionolle 100 g m-2 and standard polypropylene PP Agro 20 g m-2 - were stretched over the lettuce in the field. The covers were kept on until 4-5 days before harvest. Plots without covers were defined as the control. Ascorbic acid, soluble sugar, dry matter, nitrates, chlorophyll a, chlorophyll b and carotenoid contents were recorded in the leaves. All biodegradable nonwovens showed a positive effect on yielding in comparison to the control in 2009. In the second year of the experiment, there were no significant differences between covers with regard to the yield. Dry matter and soluble sugar content in both years of the experiment was diversified. Nonwovens used as covers in 2009 significantly increased the content of nitrates in comparison to the control. In the second year, the highest level of nitrates was demonstrated in the control object. It is worth underlining that the maximum allowed limit of nitrate content in lettuce (4000 mg kg f.w.) was not exceed. The kind of cover had no significant effect on the level of chlorophyll a in 2009 or chlorophyll b and carotenoids in 2009 and 2010 in the lettuce