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Physical and chemical treatment of poultry feather from the slaughter-house
51-56Views:286The 15-20% of the by-products of meat – and poultry industry – that unsuitable for human consumption – contains keratin. The slaughter technology of poultry produces large amount of poultry feather with 50-70% moisture content. This means more million tons annually worldwide (Williams et al., 1991; Hegedűs et al., 1998). The keratin content of feather can be difficulty digested, so physical, chemical and/or biological pretreatment is needed in practice, which has to be set according to the utilization method.
Our applied treatments were based on biogas production, which is a possible utilization method. In the IFA (TULLN) Environmental Biotechnology Institute the feather was homogenized, and – according to the previous examinations – the most effective 1:2 feather-distilled water ratio or 1% NaOH-solution was used, and then treated with microwave (70, 130, 160 °C) during 1 hour time period. DM% and oDM% content was analyzed in the original samples, and the pH, Carbon-, Nitrogen-content in the output, too. Based on the received correlation coefficients (R) and related significance values (Sig.) I concluded, that the C-, N-content and the pH values weren’t influenced by any of the additives. The temperature
affected all three tested factors. The temperature showed a strong coherency with the N-content and the pH value when distilled water was used and weak-medium coherency with the Carboncontent. With NaOH-solution treatment the temperature gave strong coherency with the C- and N-content, as well as medium coherency with the pH. Our objective was to determine the method with effectively the pre-treating of poultry feather for biogas production or composting and to prepare of the treated samples for N and C analyzing. Our next aims will be the elaboration of the technological parameters of heat pre-treatment and microbial digestion of poultry feather for biogas production. -
Anaerobe degradation of maize infected by Fusarium graminearum
57-61Views:661Last year intense rainfalls and moisture conditions were beneficial for the Fusarium sp. in Hungary. Fusarium strains decrease cereal quality (for example maize), furthermore may cause yield loss. Due to the toxin production, the fungi have a dangerous animal and human pathogen effect (Placinta et al., 1999).The effects of the Fusarium infection and its mycotoxin production haven’t been perfectly eliminated. Fusariumgraminearum
is the most common agricultural pathogen in Hungary. The utilization of infected maize as an alternative biogas raw material may be an efficient and environmentally friendly disposal method. In this case, Fusarium-, and mycotoxin-content of the maize have to be analyzed as well as the impact of these factors’ on the biogas production process. Our experience was based on the raw material basis of a biogas plant. Different amount of Fusarium free and infected maize grits have been added to the regular raw material mixture. The detection of Fusarium fungi has been analyzed
in experimental digesters throughout the different stages of mesophilic digestion. In the biogas liquid end product the Fusarium was detected by breeding and by microscope. According to our results, the Fusarium sp. was not detectable in the liquid end product after 30 days. -
Energy crops on less favoured (alkaline) soil
115-118Views:297The reduction in fossil energy and row material sources induces growing demand for renewable resources. The growing demand for herbal raw materials has land use impacts as well. One way to reduce the conflict between the food and energy crops can be the utilization of less favored areas by growing energy crops. Among the potentially available areas for this purpose the salt affected soils (SAS) occupy a significant territories. SAS with structural B-horizon (meadow solonetz soils) represent the most wide spread group of SAS in Hungary. About half of these soils have been reclaimed and used as arable land and the remaining 50% are used as grassland. Sweet sorghum production for manufacturing of alcohol production was investigated in a long term amelioration and fertilization experiment on a salt affected soil (meadow solonetz). By means of regression analyzes the effect of sodium content of the soil and increasing mineral fertilizer doses were studied. According to the multiple regression analysis only the effect of nitrogen fertilizer was significant. On the solonetz type salt affected soil the effect of water soluble salt content of the soil was not significant, but there was a closer correlation between the ammonium-lactate sodium content and the yield of sweet sorghum. The maximum green mass was 45–50 t ha-1, in the case of low Na content and high level of nitrogen fertilization.
In order to quantify the potential yield of natural grass vegetation the relationship between the soil forming processes and the grass vegetation
was investigated. Beyond the different forms of Na-accumulation, the spatial pattern (mosaic-like characteristic) is also an inseparable feature of salt affected soils. The difference in the water regime, caused by the micro-relief is the main cause of variability. The run-on water keeps the deeper parts of the catena position wet longer. The wet situation causes more intensive leaching. In the low-laying parts of salt affected soils species preferring wet situations (mainly Alopecurus pratensis) are in majority. On the higher parts of the micro-relief species tolerating dry situations (mainly Festuca pseudovina) are dominant. The yearly grass production of low laying areas can be 4–7 t ha-1 but because of prolonged wet conditions the grass is not grazed and mowing can only be in old state. This old grass is not proper for feeding, but it may be suitable as energy plant. -
Development of seed analyses by means of various matrix solutions and the MALDI-TOF MS technique
53-57Views:903The earth's population is growing steadily, currently accounting for about 7.3 billion people. Population growth causes food demand to rise, approximately 36 million people die each year due to starvation or related diseases. One solution to this problem is the continuous examination and development of the agricultural economy. In this study, matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MALDI -TOF MS) were used to analyse of sunflower, soybean and hemp. In order to analyse the protein of maize, this method has already been applied. However, for sunflower, soy and hemp, it is necessary to develop a sample preparation method. Choosing the optimal matrix solution for ionization the traget molecule is an essential part of developing the method. Our aim is to compare two different matrix solutions (α-HCCA, SA matrix), based on the properties (intensity, noise ratio, value of spectra) of the spectra.
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Vegetable production based on waste heat in closed greenhouses considering economic usage and competitiveness of the European Union
41-44Views:244The study investigates two professional fields; the questions of vegetable production in greenhouses, the necessary steam supply and heat regulations. The actuality of this investigation is provided by the planning of a combined cycle power plant of 2400 MW in Hungary. According to the plans the steam developing by generating electricity in the power plant can be used to intensify the vegetable production. In my current study I present the experiences and results gathered as member of the research and development team led by Mr. Dr. Sinórós-Szabó.
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The role of agriculture in regional development
25-30Views:857Agriculture is the leading national economic sector of Hajdú-Bihar county. The proportion of employees in this sector and the share of pro ducts produced in this region is above the country average. The contribution of agriculture to the GDP is 6.3%, as opposed to the average value of the country (3.3%). Based on their primary activity, 8% of the enterprises in the county are classified as agricultural and forestry companies, while this proportion is only 5.3% in the whole country.
Nearly three quarters (71.1%) of the sowing area is occupied by maize and other cereals, mainly wheat. This proportion is slightly more than the country average (69.2%). The proportional area of oil crops - including sunflower – and roughage is nearly the same as the country average. However, there is a significant difference in vegetable production. Due to the higher intensity of vegetable production, the area occupied by vegetables is three times the country average. 19.4% of the crop products, 23.5% of animal products and living animals, 25.8% of the income generated by production factors and 29.8% of net enterprise income of Hungary originates from the North Great Plain region.
The facilitation of creating local markets, e.g. local public food supply, satisfying the needs of food trade with local goods, the necessary awareness raising actions, secondary and higher education of experts, as well as the more specific and targeted utilisation of development resources are agricultural development tasks.
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Evaluation of the relationship between main type traits and longevity in Hungarian Simmental cows
205-209Views:487The Hungarian Simmental cattle is a dual-purpose breed, having good milk and meat production characteristics. Simmental cows have some other important traits, for example, a longer productive life. The longevity or productive life is the time period between first calving and culling. The conformation contributes to productive life, reproduction, and milk production.
The aims of this study were to analyze the longevity of Hungarian Simmental dual-purpose cows, to evaluate the effects of the size of the herd, age at first calving, main type traits (frame, musculature, feet and legs, mammary system), and combination of main type traits (frame and musculature, feet and legs and mammary system).
Animal, age at first calving, herd*calving, musculature, the mammary system as well as the combination of mammary system and feet and legs were significant effects on longevity. The highest risk ratio was observed for cows first calved after 31 months. The risk of culling increased with increasing scores of musculature and decreasing scores of the mammary system. The highest risk ratio was estimated in category 11 (lower scores of mammary system with lower scores of feet and legs). In this case, the risk ratio was 36% higher than the reference group.
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Preliminary Research Concerning the Association Between the Genotypes at the Kappa-Caseine Locus and Milk Production Traits in Cattle
45-48Views:212The genotypes for kappa-casein locus were established using PCR-RFLP. Genome DNA for PCR amplification was isolated from hair roots in cows (30 Schwitz individuals), and from frozen semen in bulls (42 bulls of different breeds).
A higher frequency of the B allele in Schwitz (pA = 0.45 and qB = 0.55 in cows and pA = 0.25 and qB = 0.75 in bulls), and a higher frequency of the A allele in bulls belonging to different breeds (pA = 0.61 and qB = 0.39 in Deutsch Simmental, pA = 0.84 and qB = 0.16 in Romanian Simmental; pA = 1.00 and qB = 0.00 in Holstein, and pA = 0.67 and qB = 0.33 in Pinzgauer) were estimated. The associations between the genotypes and alleles determined at the kappa-casein locus and milk production were tested. They emphasized significant associations only for milk and milk fat quantity, in advantage of individual carriers of the B allele in homozygous and heterozygous states. -
Energy Use of Biomass
264-272Views:266In this study, energy utilization of biomass is introduced with a short description of renewable energy sources and utilization possibilities of biomass.
Presently, the necessity of renewable energy sources is increasingly obvious. Among renewables, energy from biomass is to be highlighted, since this allows versatile, cheap utilization of the sun’s energy. In this respect, Hungary has advantages. Direct heat utilization and biogas production are available procedures today, whereas biodiesel and bioethanol are expected to spread in the near future. Biogas production is possibly the most versatile method for biomass conversion: it can produce energy from materials inapplicable for other utilization; at the same time, it is capable of neutralizing harmful wastes; in the end, it produces also valuable fermentative products, from bio-manure useful in agriculture, to pharmaceutical raw materials. -
Effects of plant density on photosynthetic characteristics and yield of maize under irrigation condition
115-118Views:516Maize plant response to plant density is an essential agrotechnical factor used for determining grain yield. Three plant densities (60,000 ha-1, 72,500 ha-1, and 85,000 ha-1) were used in this study to ascertain the effect of photosynthetic parameters and grain yield. Results show a significant difference in the photosynthetic parameters (SPAD, NDVI, LAI) and plant height for plant density of 85,000 ha-1. Grain yield and stem diameter were not significantly affected between the different plant densities.
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Effect of supplemental pig milk replacer on piglet weight gain and sow backfat thickness
43-47Views:694Sow milk production is the major factor limiting pig growth to weaning. Although the milk production of the sows incremental many environmental factors affect the actual performances. The supplemental milk replacer can be an appropriate solution to ward off disparities and try to equalize the available milk quantity to the piglets according to their appetite, to enlarge the weight of pigs at weaning, ultimately. The aim of the present study was to investigate the effects of liquid milk supplement on weight development and litter performance of the piglets during the suckling period. Data were collected from 60 farrowings, the weight of 649 piglets in a total were measured at birth, 14 days old and at weaning (28 days), respectively. In the control group (n=319) the piglets were suckled and got prestarter feed from day 10. In the experimental group (n= 330) the piglets had got liquid milk replacer in 10.71% solution, from day 10 after birth together with suckling and prestarter feed, as well. Based on the Duncan's multiple range tests, there were no significant differences in birth weight between the control and experimental group but we found significant differences between the 14 days weight and the weaning weight, subsequently. Based on the CV% of weight the experimental group became more homogenous, in contrary to the weight of the control group at the end of suckling period. The milk supplementation can be an appropriate solution to ward off disparities and to equalize the available milk quantity to the piglets according to their appetite, to enlarge and uniform the weight of pigs at weaning, ultimately.
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Weed control possibilities of „energy willow” (Salix viminalis L.)
108-112Views:261In Spring 2005, the owner of the Szalka-Pig Ltd. of Mateszalka, decided to import the willow species Salix viminalis L. and to create a plantation for energy production purposes on the humid arable lands in his ownership. In 2006, he enlarged this area by 43 hectares. The owner further decided not only to plant this species on the more adherent (KA 70), but also onto the incoherent structured sand (KA 30-35). His main argument was that the cost of coal tar derivatives as energy sources was rapidly increasing in Hungary, so he needed to find a cheaper energy source for the drying of his products and for the heating of his buildings. He also planned to change his gas and oil heating equipment.
The willow’s cropping technology is being established in our country. One of our tasks is to work out an adequate weed control plan. The professional and safe use of herbicides can increase the success of production. In our paper, we discuss the data collected on treatments applied in the pre-emergent stage. The applied herbicide combinations (terbutilazin+S-metolaklór, mezotrion+ S-metolaklór, pendimetalin+S-metolaklór, oxyfluorfen+ S-metolaklór) yielded good results in large scale experiments. -
Change of cultivation parameters of asparagus (Asparagus officinalis L.) on different nutrient systems
67-71Views:456The experiments were conducted at the Research Institute of Nyíregyháza, Research Institutes and Study Farm, Centre for Agricultural Sciences, University of Debrecen. We have studied the shoot number, plant height and fold thickness os asparagus for 3 years. We have set a fertilization experiment on 1500 m2 of plantations in 2013. We applied fertilizer, manure and sheet manure compost. The set yield we achieved by using fertilizer treatment. The Vitalim produced the largest crop, then the Cumulus and the lowest yield Grolim. We was produced by highest green mass was observed in Vitalim and Cumulus hybrids in each year. The Grolim hybrid produced the smallest shoot and plant height but the fold thickness was longer in the other two hybrids. Overall, the Vitalim hybrid has the best production parameters and each season.
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Assessment of electrical conductivity and germinability of groundnut genotype seeds
5-10Views:667Seed quality affects crop establishment and productivity. In addition, the use of good-quality seed is an essential prerequisite for sustainable crop production including groundnuts. Assessing germinability and electrical conductivity provides early evidence of the production potential of a given crop variety or genotype. Therefore, this study assessed the germinability and electrical conductivity of seeds of three groundnut genotypes. A laboratory experiment arranged in a Completely Randomized Design (CRD), replicated three times, was conducted at the Faculty of Agriculture, Kyambogo University, in 2020. Seeds of Igola, Serenut 1, and Serenut 2 groundnut varieties were tested, and data was collected on germination percentage and electrical conductivity. Analysis of variance (ANOVA) was performed using GenStat and means were separated using the least significant difference test at a 5% probability level. Germination percentage and electrical conductivity significantly (p<0.05) differed among the groundnut varieties, with Igola recording the highest germination percentage, followed by Serenut 1, and the lowest was in Serenut 2. The highest electrical conductivity was recorded in Serenut 1 and the lowest in Igola. Since Igola had one of the lowest electrical conductivity and the highest germination percentage, it was concluded that Igola genotype retained higher quality attributes.
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Comparison of Scab Warning Systems in Integrated Apple Production
53-57Views:338In the present study, the suggestions for infection risk and sprays of the most frequently used PC-based scab warning systems (RIMpro and WELTE) and the conventionally used Mills table as a reference were compared in integrated apple production. The efficacy of the spraying programs based on the three different warning systems was evaluated by assessment of apple scab incidences during primary infection periods.
13 and 11 Mills infection periods were detected in 2000 and 2001, respectively, during primary infection periods (from 15 March until 5 June). Taking into consideration the heaviness of Mills infection periods, 11 and 9 sprays were applied in 2000 and 2001, respectively. The two PC-based scab warning systems detected 1-4 less infection periods and suggested 1-3 less sprayings compared to the numbers of infection periods and sprays according to the Mills table. Our results proved that the 9-11 sprays according to the Mills table could be reduced to 7-9 sprays by RIMpro scab warning systems which did not reduce the efficacy and did not increase the symptoms of leaf and fruit scab significantly. The WELTE scab warning systems detected generally one or two more infection periods and suggested one additional spray compared to RIMpro warnings and sprays. -
Using sensors in precision crop production
267-270Views:316Proper plant nutrition that takes into consideration both the requirements of plants and ecological conditions is one of the most important precondition of successful plant production. An important element of the N-fertilization of wheat is that the optimum zone of nitrogen supply is significantly narrower than that of other plant species, therefore it can easily happen that we apply higher or lower nitrogen doses than the optimal one. A possible solution to this problem can be precision agriculture. Applying the methods of precision agriculture we can take into consideration the heterogeneity of fields. By applying precision methods either online or offline we can intervene faster than if we would rely only on regular soil and plant analysis procedures. The determination of the doses of nitrogen and the timing of application are influenced also environmental and
economic aspects. The chlorophyll content of the leaves indicates the nitrogen status of plants, since there is a relationship between the nitrogen content and the amount of chlorophyll in the leaves. According to plant analysis results there was a strong and significant relationship between the values of the NDVI (Normalized Difference Vegetation Index)and the total nitrogen content measured in the leaves. -
Application fields of wood as a renewable energy source in Europe
31-35Views:289Fuelwood, and wood wastes provide almost half of the renewable energy production of the European Union. Enhancing the use of wood in renewable energy production has more constraint than wind- or solar energy. Forests in the EU member states are sustainably used, they are increasing both in terms of area, and growing stocks. There are possibilities to enhance the fallings and use more fuelwood. Short rotation coppices could fulfill the long term demand for fuelwood; because these plantations surpass the dendromass yield of forests.
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Examination of the impact of sowing technology models on the ear, constiuent and yield parameters of the yield formation elements of maize hybrids of different genotypes
17-23Views:295Production year 2012 has been characterised by climatic extremities. The weather of this year can be considered very contradictory in terms of maize production. The droughty conditions of the winter and spring months had a negative effect on both germination and starting vigour. The favourable weather of May-July created ideal conditions for intensive growth and generative processes; however the lack of precipitation in August and September had a damaging effect on the development of yield composing elements and grain saturation processes as well. Under such circumstances, the sowing date models caused significant differences in the yield and quality of the hybrids belonging to different growth periods. The growing period of the maize hybrids has been shortened as a result of the unfavourable climatic conditions.
Based on the trial results, it is verifiable that short growing period hybrids can be securely sown in draughty years even with a later sowing date, however using a later sowing date in the case of longer growth period hybrids may result even in a yield loss of 2–3 t ha-1. In the case of early and average sowing dates, with given yearly conditions the hybrids of the observed FAO 370-390 hybrid group provided the best result (12.40 t ha-1, 10.99 t ha-1), while in the case of the third, late sowing date the yield dominance of the FAO 290-350 hybrid group is the most significant (10.08 t ha-1).
The analysis of the yield composing elements found that the P9578 hybrid has the highest shelling ratio, while its cob is the shortest. The P9494 hybrid has a high yield and the highest thousand grain weight, while the DKC 4983 has the longest cob and its thousand grain weight is above 300 g.
The results confirm the fact that DKC 4590 has the highest yield potential and starch content, while in terms of oil and protein content the Szegedi 386 and NK Octet hybrids are the most important.
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Study on the Work Organization at Dairy Farms
293-296Views:279Joining the European Union Hungarian producers have advantages but they need to solve some problems too. Only those producers can compete who will be able to produce extra quality milk. However the circumstances of milk production are not up to the task.
The author examined the work organization of 7 dairy farms in Hajdú-Bihar County. Data were collected about the situation of farms, equipment of barns, objets of production, work force, qualification of workers, and productivity of work. He examined the applied motivation methods at farms. He concluded that as the number of cows per farm increases work productivity increases too. From the examination it appeared that family farms applied different motivation system from bigger producer organizations. The author put forward proposals for motivation possibilities to improve milk quality, atmosphere, and general feeling of workers. -
The use of essential trace elements in the juvenile rearing of barramundi (Lates calcarifer
33-38Views:521Barramundi (Lates calcarifer L.) is a predatory fish species native in Southeast Asia and Australia. Based on the geothermal potentiality of Hungary the warm-water fish can be reared successfully. Zooplankton in the wild contains minerals in a higher concentration than the usually fed newly hatched Artemia nauplii, therefore essential trace elements, such as cobalt, zinc and manganese play an important role in the larviculture of barramundi. Cobalt is vital in trace amount for many living functions of vertebrates, however, lower number of papers are available considering the nutritional aspects. Nevertheless. improved growth performance was observed in cases of some fish species when diet was supplemented with CoCl2. Zinc and manganese are also vital for optimal growth and accordingly are investigated and applied diet supplements in aquaculture.
The main aim of the recent study is to investigate the effects of cobalt, manganese and zinc on the growth performance and homogeneity of fish when a commercially available dry diet is supplemented with trace elements individually and in combined treatments. A total of 6 treatments were set in a randomized blocked design where the concentrations of the applied elements were 50 mg kg-1 for CoCl2, for ZnSO4 and for MnCl2 individually, as well as for CoCl2 along with ZnSO4 and for CoCl2 along with MnCl2 in combination. Although the production parameters of larval barramundi were positively affected by the addition of trace elements when the retention of minerals occurred through nourishment living organisms, statistically no differences were found between the treatments considering the growth performance of barramundi juveniles either when dry feed was supplemented with cobalt, manganese or zinc (p>0.05). While the use of cobalt and manganese in combined treatments produced a less uniform larvae in size and as a consequence of increased heterogeneity, survival was significantly reduced by the cannibalism, the sizes distribution of barramundi juveniles wasn’t affected by the dry diet supplementation of these elements.
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Evaluation of vegetative and generative characteristics of some ‘Gala’ cultivars
15-20Views:291The aim of this study was to evaluate the production characteristics of new ‘Gala’ apple cultivars (‘Gala Venus Fengal’, ‘Gala Decarli- Fendeca’, ‘Galaval’, ‘Jugala’, ‘Gala Schnitzer (S) Schniga’), which can be described with superior and earlier fruit surface coloration and with larger fruit size comparing with the origin cultivar, however they are less well known in our country. The place of our experimental is located in the Nyírség representing adequately the ecological conditions of the surrounding areas, so the gained results can be easily adapted in the biggest apple production site of Hungary. According to the results it can be stated that among the 3–4 years old ‘Gala’ trees, which will achieve the maximal yields just in the next years regarding yields the ‘Fengal’ and the ‘Fendeca’ cultivars are emerged (43–46 t ha-1).
Furthermore they reached also excellent fruit quality (70–75 mm diameter). The fruit quality of the ‘Galaval’ is also optimal, but the yields are notably smaller. The ‘Jugala’ produced lower yields and the coloration of the variety is also insufficient. In the case of the ‘Schniga’ the excessive increasing yields can cause quality loss easily.
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The potential use of Pediococcus spp. probiotic in aquaculture: A review
99-106Views:725Aquaculture production has significantly increased over the previous few decades. However, antibiotics have been implemented regularly and extensively to overcome outbreaks of pathogens in aquaculture to cover the human needs for animal protein, leading to the appearance of resistant strains that may cause serious damages in the environment and also human health. In the last few years, the implementation of probiotics as an alternative technique to antibiotics use in fish production has achieved promising results in aquaculture due to their beneficial impact on fish health and growth performance. Among different types of probiotics, the Pediococcus spp. bacteria stand out as a promising probiotic for their beneficial impact to aquaculture. Thus, the current study has been conducted to give an overview about the interactions between Pediococcus spp. and aquaculture. In addition, this review highlights the role of Pediococcus spp in promoting growth performance, improving feed conversion ratios and the intestinal architecture, enhancing the immune response and inhibiting fish pathogens, thereby preventing or at least reducing the use of antibiotics. Practical use of Pediococcus spp. probiotic in aquaculture as feed additives through selected case studies is also considered.
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Seedling morphology of different wheat genotypes at early stages under hydrocultural conditions
249-254Views:533Consuming “sprouted seeds” is one of the most important factors of a healthy diet. An experiment was conducted in the University of Debrecen, Research Centre of Nyíregyháza (Hungary) in 2014 to analyse some morphological traits of four winter wheat genotypes (Triticum aestivum L.) and one spelt (T. spelta) variety. Our results showed that the spelt wheat variety “Franckenkorn” could maintain higher root length throughout the experimental period. On average, both “Perbetei” and “Franckenkorn” varieties could maintain higher root number compared to the other varieties. The extensive breeding line “1401 HK” had the highest shoot length throughout the whole experiment, being significantly higher than the landrace variety “Perbetei” and both of the varieties “KG Bendegúz” and “KG Kunhalom”. It could be concluded that “KG Bendegúz” cultivar and “Perbetei” landrace seem to be the most suitable for aquaculture techniques. In addition, “1401 HK” breeding line can be the most suitable for the production of juice since the minimal required shoot length (12 cm) was achieved within the shortest period of time after sowing (9 days). This breeding line and “Franckenkorn” can also be suitable for production of “wheatgrass”, because it is consumed without roots. Further research is needed to evaluate nutritional values of these genotypes.
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Effect of Water and Nutrient Supply on the Allelopathy of Abutilon theophrasti Medic. and Xanthium italicum Mor
102-105Views:244Velvetleaf (Abutilon theophrasti Medic.) and Cocklebur species (Xanthium spp.) are more and more dangerous and „difficult to control” weeds in several cultivated plants. The ground cover of these species have became larger in Hungary like other warm-philous species. There are several causes of danger of them, for example: large capability for competition, allelopathic effect, keeping on of emergence.
The allelopathic effect of these weeds were examined on sugarbeet (Beta vulgaris L.). Extracts of plants grown under different conditions have several effect on this species.
Abutilon theophrasti plants were grown in perlite to examine the effect of supplying with nutritive materials on production of inhibitors. The water soluble exudates of the shoots grown with no artificial fertilisers inhibit stronger than grown with them. Acid soluble exudates have contrary effect. The exudates made of roots inhibited the sugarbeet less than shoots.
Effect of drought stress on production of inhibitors was examined on Abutilon theophrasti and on Xanthium italicum. The species responded to missing of water different, and the water, acid and basic soluble exudates had different effect, as well. -
Preliminary results of intraspecific sterlet hybrid (Siberian sterlet × sterlet) rearing under intensive conditions
17-19Views:294Due to early maturation and a small size, sterlet (Acipenserrut-henus) is a very advantageous fish for intensive sturgeon farming with regard to caviar production. According to our previous observations, the growth potential of Siberian sterlet (A.ruthenusmarsiglii) is higher than that of the European one. In our experiment, sterlet and an intraspecific hybrid (Siberian sterlet × sterlet) were tested under intensive tank conditions. During the 8 weeks of the experiment, survival, growth and size heterogeneity were investigated. According to the results, there were no significant differences in survival and growth but the size heterogeneity was higher in the hybrid. It is supposed that, in our trial, the applied water temperature range (24.0–25.5 °C) was optimal for sterlet, but was probably above the optimal range for the hybrid.