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Evaluation of water balance in apple and pear trees
193-198Views:611A significant proportion of the aboveground green and dry weight of the plant constitutes the foliage. The canopy is an important factor
of plant growth. On one hand the canopy absorbs the solar energy, which is necessary for the photosynthesis, on the other hand accumulates
the absorbed nutrients by the roots, and the most of the water-loss happens through the foliages. The determination of the full canopy is not
an easy target. In our research we developed a measurement method to determine the leaf area. With the parameters of the examined tree
(leaf length and maximum width) and the data of ADC AM 100 leaf area scanner we determined the k-value, with which we can easily and
fast evaluate the leaf surface. Furthermore we defined from the water balance of compensation lysimeters the cumulative transpiration of
fruit trees and the efficiency of water use of trees. -
The effect of sous-vide cooking on the antioxidant properties of oyster mushroom (Pleurotus ostreatus L.)
177-184Views:734Oyster mushrooms (Pleurotus ostreatus L.) are renowned for their antioxidant, antimicrobial, and prebiotic properties. This study explores the antioxidant characteristics, activity, and β-glucan content in freeze-dried mushroom samples, investigating the influence of sous-vide cooking. Uncooked freeze-dried P. ostreatus and three pre-cooked freeze-dried samples (70, 80, 90 °C through 4 hours) were analysed for Total Polyphenol Content (TPC), Total Flavonoid Content (TFC), Radical Scavenging (DPPH), Ferric Reducing Antioxidant Power (FRAP), and β-glucans content via HPLC and Total Dietary Fiber (TDF) via enzymatic gravimetric method. Results indicate that uncooked mushroom powder exhibited superior antioxidant capabilities compared to cooked samples. The sous-vide cooked (80 °C) mushrooms displayed the highest total phenolic and flavonoid content. Moreover, pre-cooked (70 °C) mushroom powder demonstrated the highest β-glucan content, significantly surpassing the uncooked control sample. Notably, pre-cooked groups (80, 90 °C) demonstrated significantly higher TDF levels compared to uncooked sample. This research offers valuable insights into the potential use of mushrooms as high-antioxidant, antimicrobial, and prebiotic food or feed supplements, with broad implications across various fields.
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The Role of the Digital Terrain Models in the Assessment of Surplus Water Risk at the Szolnok-Túri Plain
47-51Views:377The environmental factors to which surplus water can be assigned (topography, soil, groundwater, vegetation etc.) can be subject to special analysis and the randomness of the occurrences can be limited. The results of these procedures are surplus water risk maps of the areas, which can be utilised in land use planning. The risk map of the research site was created with overlaying digital category maps of the determining factors (hydraulic conductivity, convexity, critical probability of ground water level and land use).
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The effects of agrotechnological factors on winter wheat yield in humid cropyear
162-167Views:354The effects of crop rotation, nutrien supply and crop protection technologies, as well as the appearance of the main ear- and leafdiseases
(powdery mildew, helminthosporium leaf spot, leaf rust, fusarium) were studied on the crop yields of winter wheat variety MV
Pálma during the 2009/2010 crop year. The experiments were conducted in triculture (pea – wheat – corn) and biculture (wheat – corn), at
five nutrition levels, with the use of three crop protection technologies (extensive, conventional and intensive) at the Látókép Research Site of
the University of Debrecen, Centre of Agricultural Sciences. Our results proved that the appearance of leaf- and ear-diseases were
significant in the wheat cultures during the 2009/2010 crop year, because of the rainy, warmer than usual weather, the lodging, and the huge
vegetative mass developed. The most severe infections by the four examined diseases after pea and corn pre-crops were observed at
extensive crop protection levels, when fertilizers were used at the highest dose.
Following corn pre-crop, in the case of all the three crop protection technologies the maximum rate of wheat yield results were achieved
at N150+PK level. The highest yield was reached at intensive crop protection level (6079 kg ha-1). In triculture, in case of all the three crop
protection technologies the maximum yields were achieved at N50+PK level; in extensive technology 5041 kg·ha-1 yield, in conventional
technology 6190 kg ha-1 yield was realised, while in the intensive technological model the yield was 7228 kg ha-1.
The relationship between yield and fertilizer amounts, the rate of pathogen contaminations, crop protection technologies and pre-crops
was defined with correlation analysis in case of different crop rotations during the 2009/2010 crop year. Based on the results of the
experiment, we found that in stands after corn pre-crop strong positive correlation was established between the crop protection level and the
crop yield (0.543), the nutrient levels and the emergence of the four examined pathogens, and between the nutrient levels and the yield
(0.639). Extremly strong positive correlation was observed between crop protection and yield (0.843) in triculture. Strong positive
correlation was detected between the nutrient levels and the presence of the four examined pathogens, as well as between nutrient and
lodging (0.688). Strong negative correlation was between the crop protection level and the four examined diseases both in biculture and
triculture. -
Nest-site preference of Hooded Crow (Corvus cornix L.) in Debrecen, Hungary
13-17Views:426In the past decade, the population of the Hooded Crow has shown significant growth in Debrecen, Hungary. The aim of this study was to become acquainted with the nest-site selection behavior of Hooded Crows in urban spaces. While our research revealed that the Hooded Crow is not particular when it comes to selecting among tree species for nesting, we did notice differences regarding nesting height. Hooded Crows living in the city build their nests higher up than those living outside Debrecen’s city limits. We also discovered a slight, insignificant difference between nesting heights and tree species, which is probably due to the different characteristics of the given tree species. As for nesting heights, we found that in typical urban habitats there were no relevant differences. However, when we compared these habitats in pairs, it came to light that nesting heights -when comparing solitary trees - wood segments and tree rows - wooded segments- did show significant differences, which can be explained by the various conditions provided by the habitats mentioned.
In summary, the following results emerged from our research:
1. The Hooded Crow prefers approximately the same nesting heights in all kinds of habitats, urban environment and tree species.
2. The nesting height does not significantly depend on the habitat itself or on the tree species. -
Pathogenic fungal pathogens and diseases: a mini review of effects on maize production
93-102Views:265Maize, the most important cereal globally in terms of nutrition and income, is highly susceptible to biotic stresses caused by various pathogens, including fungi, bacteria, viruses, nematodes, and parasitic plants. This review gives an account of the epidemiology, diversity, and effect of fungal diseases on maize, with a focus on common pathogens, namely Ustilago sp. and Fusarium sp. Additionally, the review explores the major contributors to the pathogen and disease development, namely: soil quality, temperature, and humidity. Clarity is made herein about the damages and effects on maize growth, including development, yield, and grain quality, with marked economic losses recorded annually. The increasing threat of climate change escalates the dangers, pointing out the urgency for sustainable control strategies of the diseases. Conventional methods of using chemicals have been rendered inadequate for maize fungal disease control, underscoring the need for applying biopesticides and natural products obtained from microorganisms as innovative, remediation strategies. Together with these innovations are biocontrol agents that provide better solutions for reducing the reliance on chemical formulations as well as strengthening a healthier agricultural environment. Finally, a comprehensive understanding of the interaction between maize pathogens and environmental determinants is vital for the development of more effective integrated pest management strategies to enhance maize productivity and subsequent food safety.
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Microbiological quality of bulk tank raw milk from two dairy farms in Hajdú-Bihar County, Hungary
105-112Views:641Two main channels have been identified to be responsible for microbiological contamination of raw milk and milk products. Firstly, contamination has occurred due to udder infection from the cow or the blood which harbours most bacteria that come in contact with the raw milk. Secondly, via external factors (may include faeces, skin, contaminated water, environment etc.) which are associated with the operation of milking. There is direct contact with the milk and/or surfaces before, during or after the milking, posing public health risk and economic decline. The aim of this study was to examine the bacteriological quality of bulk tank raw milk samples collected from two different size dairy farms (Farm 1 and Farm 2) of different housing forms (cubicle loose and deep litter) in Hajdú-Bihar County, Hungary in July, 2017. Three samples were taken from each farm, and the total plate count, coliform count, Escherichia coli count, Staphylococcus aureus count, and yeast and mould count were determined in them.
The results clearly showed low level of all measured bacteria group load in Farm 1 samples in comparison to Farm 2 with the exception of coagulase-negative Staphylococcus (CNS) which represented high level in general, indicating significant difference (P<0.05). The mean value of total plate count in Farm 2 samples was higher (1.0 × 105 CFU/mL) than Farm 1 samples (2.8 × 104 CFU/mL). There was a significant difference (P<0.05) in mean count of coliforms in raw milk samples between Farm 1 and Farm 2. Similarly, results of E. coli were significantly different (P<0.05) with mean count of 1.44 × 102 CFU/mL and 2.02 × 103 CFU/mL for Farm 1 and Farm 2 respectively.
Results of Staphylococcus aureus also showed significant difference (P<0.05) with mean count of 9.7 × 101 CFU/mL for Farm 1 and 6.28 × 102 CFU/mL for Farm 2. The mean of mould count recorded was 1.07 × 102 CFU/mL and 4.93 × 102 CFU/mL for Farm 1 and Farm 2 respectively. The recorded mean of yeast count was 1.68 × 103 CFU/mL and 3.41 × 103 CFU/mL for Farm 1 and Farm 2 respectively; however, both farms showed no significant difference (P>0.05) in terms of mean of mould and yeast count. Although Farm 2 produced six times lower milk quantity than Farm 1, the measured microbial parameters were high. Both farms’ microbiological numbers were higher above the permitted limit values as stated by Regulation (EC) No 853/2004, Hungarian Ministry of Health (MoH) 4/1998 (XI. 11.).
This could be an indication of non-conformance to effective GMP, ineffective pre–milking disinfection or udder preparation, poor handling and storage practice, time and temperature abuse and inadequate Food Safety Management System Implementation. Therefore, our recommendation is as follows; establish control measures for pre- and postharvest activities involved in the milking process which would be an effective approach to reduce contamination of the raw milk by pathogenic microorganisms from these farms, strict sanitation regime and hygiene protocol be employed and applied to cows, all equipment, contact surfaces and minimize handling of the milk prior, during and after milking. This will also serve as scientific information to the producers for continual improvement in their operations.
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Bacteria in the milk of sheep with or without mastitis- mini Review
47-52Views:666From a nutritional point of view, sheep milk is more valuable than cow and goat milk and the interest for sheep milk is increasing in many countries. However, sheep milk is easily contaminated during milking, handling, and transport and it is an ideal medium for bacterial propagation. Consequently, sheep milk spoils quite quickly. The proper, clean handling of milk is not only of sanitarian interest, but it also serves the farmers’ interests, because contaminated milk may not be distributed, and is unsuitable for producing good quality products. Following this technological trend, this review addresses the bacterial composition of sheep milk with and without mastitis. Even though sheep milk contains a lot of bacteria, this review article highlighted total plate count, Enterobacteriaceae, coliform, Staphylococcus aureus, Escherichia coli, Listeria monocytogenes, Campylobacter, Salmonella spp. and Streptococcus spp. Mastitis in sheep is a vital cause of mortality, reduction in milk production and early culling. The reported risk factors for mastitis in sheep were age, a case of mastitis, breed, husbandry systems, and location. The main priority should be implementation of programs to minimize human pathogenic bacteria and mastitis in raw ewe milk.
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Application of semen evaluation techniques
5-11Views:648Laboratory methods of semen evaluation are used to select males for artificial insemination. The current review describes several techniques that have been recently used for sperm analysis. Conventional microscopic methods in combination with the objective computerassisted sperm motility and morphology analyzers and flow cytometry, allows to obtain more precise information about the membrane and functional status of spermatozoa. By using several methods to detect motility, viability, acrosomal and capacitation status besides DNA integrity sperm biology and some of the mechanism involved in sperm cry injury can be better understood. The number of possible targets related to sperm quality is increasing, and possible that some of them could enable sperm analysis for predicting freezability and fertility to be improved.
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The effect of dissolved oxygen on common carp (Cyprinus carpio) and basil (Ocimum basilicum) in the aquaponics system
89-96Views:1079Aquaponics is an integrated system that combines fish farming (aquaculture) and hydroponic plant production. The objective of this study was to examine how the level of dissolved oxygen with or without an air pump affects water quality, fish output and plant growth parameters for common carp (Cyprinus carpio) and basil (Ocimum basilicum).
Ebb – and flood aquaponics systems (with automatic syphon) was used. Two treatments were set in this experiment, one of which was the aquaponics system without air pump (unit I), where water of the plant bed was pumped two directions, one falling back to the fish tank oxygenating the water the other was pumped to the hydroponics unit. The other system (unit II) was designed with an air pump.
In the course of the study, water quality parameters, such as oxygen saturation, dissolved oxygen (DO), electrical conductivity (EC) and nitrite were significantly different (p<0.05). Total basil biomass was higher in unit II. (5367.41 g). The final biomass of common carp were
2829.45 g ± 79.24 and 2980.6 g ± 64.13 g in unit I and unit II respectively. Weight gain (WG) and specific growth rate (SGR) showed no significant differences (p>0.05) between the treatments. -
Comparison of the technological background of aquaponic systems
47-52Views:779Aquaponics is the combined culture of fish and plants in recirculating aquaculture systems, an ecologically sustainable horticultural production technique with long traditions.
The objective of this study is to compare flood-and- drain, and the water crossflow system and examine the differences in the water quality, fish yield and plant growth parameters for Common carp (Cyprinus carpio) and basil (Ocimum basilicum). During the study, water quality parameters of two treatments were compared in temperatures, pH, EC and NO3¯N were significantly different (p <0.05). Leaf area of the basil plants grew to an average of 20.37 cm2 (± 9.02 cm2). The plants’ biomass production was significantly different (p< 0.05) in the two systems. The biomass production showed lower yield, 458.22 g (± 214.59 g) in the constant flow system that in the flood- and- drain system 692.9 g (± 175.82 g). Fish Growth parameters were better in constant flow system (FCR 5.48 g/g ± 0.19). However, the specific growth rate (SGR) demonstrated that fish grew faster in flood- and- drain system 1.38 %/day (± 0.29).
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Evaluation of chickpea (Cicer arietinum L.) in response to salinity stress
105-110Views:819Soil salinity is a severe and expanding soil degradation problem that affects 80 million ha of arable lands globally. Chickpea (Cicer arietinum L.) is very sensitive to saline conditions; the most susceptible genotypes may die in just 25 mM NaCl in hydroponics. Approximately 8–10% yield loss in chickpea production is estimated due to salinity stress. However, it is still not established why chickpea is so susceptible to salt affection. Salinity (NaCl) impedes germination of seeds, though chickpea varieties considerably differ from one another in this respect. Some chickpea genotypes are more tolerant in the stage of germination, tolerating even 320 mM NaCl. The reasons of this variation are unrevealed; there is a shortage of knowledge about the germination abilities of chickpea genotypes in saline conditions. Nevertheless, the effect of salt stress on vegetative growth can be analysed in hydroponics, in pot or field conditions, regardless the experimental environment, the ranking of genotypes regarding salt resistance is coherent. Chickpea genotypes can be different in their ability to retain water, maybe under salt affection; the more salt tolerant lines can maintain higher water content in the shoots, while the more sensitive ones cannot. The identification of salt tolerant chickpea landraces based on developing genetic variability is a suitable strategy to combat against salinity problems arising in arid and semi-arid areas.
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Reference genes for livestock gene expression profiling – Literature review
81-89Views:563Quantitative real-time polymerase chain reaction (qPCR) is an essential tool for understanding animal cell’s response to developmental progression or to different experimental conditions at gene expression level. However the reliability of this method heavily lies on proper normalization (measuring a target and a reference gene’s expression from the same sample to correct for technical related variations).
Our literature review aimed to summarize the articles addressing the most important livestock species in regards of reference gene stability used as normalizers for quantitative real-time polymerase chain reaction experiments. Stably expressing reference genes were categorized into 14 distinct groups according to gene function. The number of reference genes tested and the publication numbers according to years and the ranking algorithms were also noted.
Counting showed that genes encoding ribosomal protein components are ranked as most stable in majority of cases and therefore should be taking into account for qPCR stable normalizer gene finding experiments. -
Biological control of sweet chestnut on Pécsbánya, Hungary
77-81Views:492The supervision of plant hygiene of sweet chestnut grove on Pécsbánya (South Hungary) started more than four years ago. Hypovirulent strains were applied as a biological process to control Cryphonectria parasitica fungus which causes the chestnut blight disease. By now the performed interventions have shown obvious results, the vitality of the trees has greatly improved, the amount of harvested nuts is increasing, and the hypovirulent strain has been spreading within the area. During plant health inspection the galls of chestnut gall wasp (Dryocosmus kuriphilus) was found in the year of 2015, which is the obvious symptom of new occurrence of the pest. The pest was eradicated by destroy galls, which allows taking out of consideration the damage by now in this area.
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Comparative study of special honey products and herbhoneys
117-120Views:816Honey has a positive effect on human body due to its high content of biologically active substances (e.g. monosaccharides, vitamins, enzymes, amino acids, polyphenolic compounds). The properties of honey depend on its botanical origin due to the bioactive plant components, mainly secondary metabolites that are included in honey made by bees from nectar. Herbally infused honeys are delicious products that combine the therapeutic action of herbs and honey. Additionally, herbs can provide nutrient fortified syrup for honey bees and protect them against diseases and other ecological threats.The aim of this study was to define the physicochemical properties of multifloral honey, herb enriched natural honey and herbhoney samples. We measured the moisture content, pH value, electrical conductivity and proline content. Although great diversity was observed in the basic properties of the examined products. In our study, we found that the electrical conductivity shows the significant differ between the groups. All the samples, including the herbhoneys passes the quality standards of honeys. -
Investigation of harvest index influencing agrotechnical and botanical factors in hairy vetch (Vicia villosa Roth.)
123-128Views:495The biggest problem of Hungarian crop farming is mass production and the simple crop rotation based on cereals. There was a decrease in sowing area of protein crops which raises crucial issues in crop rotation and land use. Therefore, growing papilionaceous plants, which are now considered to be alternative plants, should be taken under close examination. Hairy vetch (Vicia villosa Roth.) belongs to the family of papilionaceous plants and it can be grown in light weak soils.
In Hungary, hairy vetch was used as green forage at first, but it later became a green manure plant. Nowadays, it is used as a cover crop and its sowing seed has a good export market. In low fertile soils it is able to produce a big amount of green yield (25–40 t ha-1) even in spring while its seed yield could be 0.4–0.5 t ha-1 at farm level. In addition to its morphological characteristics hairy vetch is grown mainly with a supporting plant, i.e. triticale in many cases.
Our purpose was to test the harvest index and its agrotechnical and botanical factors of hairy vetch in different cropping systems.
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The status of conservation and management of indigenous sheep breeds in South Africa - A review
79-91Views:625Indigenous sheep breeds in South Africa play an important role in local food security and they are adapted to local conditions. Their genetic and cultural values have to be recognised for national importance. The conservation of these breeds is very critical as most of them are already classified as endangered. The South African government has the initiative to attempt the conservation of these animals; however, it comes with several challenges. In addition to funding, breed conservation demands farmers to understand and recognise the role of such breeds in society. This is especially crucial in the rural communal lands where breeds are kept. Farmers that raise indigenous breeds should be taught the necessity of maintaining the purity of these breeds. Indigenous sheep breeds in South Africa are not favored by the commercial farmers and thus they are more vulnerable. This review outlines the nature of sheep farming and the conservation status of four indigenous sheep breeds in South Africa. The effort and challenges that are met in current conservation arrangements are discussed. Moreover, we emphasise on the conservation techniques that are employed in South Africa.
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Angle-count sampling method for estimating forest stand volume – a practical approach
99-102Views:434Point sampling, which is also known as angle-count sampling (ACS), can be considered an efficient way of estimating the basal area and volume of forest stands. It is possible to use it in forest management: providing more accurate estimates (precision <10%) of site and stand characteristics needed for management planning. 20 black locust (Robinina pseudoacacia L.) stands were selected at final cutting age to determine the regeneration criteria based on their total volume. It was verified that at P=5% there was no difference between the main volume values of stands indicated in the relevant forest plans as well as calculated by the ACS method.
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Impact of tillage systems on maize emergence
129-136Views:431In Europe, there has been a significant change in the way tillage is approached in recent years. This change is due to a growing awareness among farmers, politicians and society as a whole that soil is not a renewable resource in itself. From an agricultural point of view, the greatest impact on soil condition can be achieved through the use of the applied tillage systems. My research takes this approach as a basis when examining the different tillage systems and their impact on the environment. In this context, conventional and a variety of no-tillage systems are examined in this paper. As a next step, it is examined how the environmental conditions created by the different tillage systems influence the emergence of maize hybrids. The analyses are carried out in a multi-factorial, long-term tillage field experiment. The same batch of the same hybrid seed was sown in several crop years, and the effects of environmental conditions on the emergence process were examined. Environmental effects and emergence-related uptake were measured in the examined plots. Measurements of environmental effects included air temperature, precipitation, soil temperature measured at seeding depth, as well as % cover of stem residue on the surface in the treated plots. The first emergence time measurements of the sown crop in the plots of each treatment were compared and relationships between these factors were investigated.
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Improvement of black locust (Robinia pseudoacacia L.) growing under marginal site conditions in Hungary: case studies
129-133Views:566In Hungary, black locust (Robinia pseudoacacia L.) is considered as an important exotic stand-forming tree species growing mostly under unfavourable ecological conditions for forest management. Due to climate change effects, its importance is increasing in many other countries, too. As a result of a selection programme, new black locust clones were tested in clone trials. Juvenile growth of 12 micropropagated black locust clones in two plots series established at different dates were evaluated in central Hungary under marginal site conditions. At age of 7 the clone R. p. ‘Bácska’ (‘KH 56A2/5’), at age of 10 the clones R.p. ‘Homoki’ (‘MB17D3/4’) and ‘PV201E2/4’ appeared to be especially promising for mass production. Based on the data obtained from the performed trials, it can also be concluded that tissue culture can be considered as a suitable tool for propagating superior individuals and offers new prospects for the rapid cloning of selected genotypes used for plantation forestry.
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The effect of different compost rates on the yield of ryegrass (Lolium perenne L.)
95-98Views:318Protection of natural resources and sustainable natural resources management are essential for the long-term survival of humanity. This makes necessary nowadays the development of environmentally conscious living and spread of that in the future. The amount of organic waste materials, produced during human activities, could be decreased by composting instead of dispose them in landfills. Applying appropriate treatment technology and additives, the compost could be used as fertilizer for horticultural crops and it could increase the easily available nutrient content of soils. Compost utilization prevents nutrient deficiencies and by using the optimal rate, we could reach significant yield increases.
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Biological potential of plant pathogenic fungi on weeds: A mini-review essay
59-66Views:657The invasion of weeds into productive areas has substantial negative effects on native ecosystems as well as agricultural production systems globally. Consequently, the task of maintaining or restoring these systems will become increasingly challenging without consistent, ongoing management efforts. The intensifying emergence of herbicide resistance in numerous weed species, coupled with the unintended pollution caused by synthetic herbicides, underscores the growing necessity for alternative, environmentally friendly, and sustainable management techniques, such as the utilisation of bioherbicides. Plant pathogenic microbes play an important role in biologically management of weeds, with the utilization of plant pathogenic fungi emerging as a promising area of study for novel research trends aimed at weed management without reliance of herbicides and to mitigate environmental pollution. A potential solution to decreasing pesticide usage involves the development of bioherbicides containing fungal active ingredients. Among the most commonly utilised fungi in bioherbicides are genera like Alternaria, Colletotrichum, Cercospora, Fusarium, Phomopsis, Phytophthora, Phoma, and Puccinia. Increased weed resistance to herbicides has influenced new strategies for weed management, with some fungi from genera such as Colletotrichum and Phoma already employed for weed control. Nonetheless, it is evident from reviews that further research is imperative in this domain, with particular emphasis on analysing the efficacy of each plant pathogenic fungi.
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The significance of local meteorological stations in research planning
87-91Views:420The goal of research planning is to optimize human and material resources while maximizing efficiency. If there are databases that can be used as a substitute for own data collection, effective research can be facilitated by reallocating resources. In the case of environmental studies, the knowledge of the climatic conditions of the study period is known to be a key factor in research planning process.
In the present study, the data of our meteorological station in our research area (known as “Szamárháti Tanya”, Kesznyéten, Hungary) was compared with the measurements of meteorological stations operated by the competent water authority. Stations were taken into the study within a 10 and 20 km radius over a period of 21 months, to determine which provided more relevant data from the area.
During the evaluation of results, the relationship between the local and regional weather stations were determined, and deductions were made from the obtained results to support the decision which of the targeted investigations could be of greater benefit.
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Examination of drought stress of two genotype maize hybrids with different fertilization
53-57Views:338In the growing season of 2019, we analysed stress resulting from climatic factors on maize hybrids of different genotypes, with the aim of gaining a better understanding of the physiological responses of each hybrid, which might support the elaboration of a cost-effective irrigation plan.
Our experiments were carried out at the Látókép Experimental Station of the University of Debrecen on calcareous chernozem soil in a small-plot long-term field trial with strip plot design. In the scope of the experiment, N-fertilizer doses were applied as basic fertilizer and top-dressing in addition to the non-fertilized (control) treatment. The 60 and 120 kg N/ha doses applied as basic fertilizers in the spring were followed by top-dressing in the V6 phenophase with a +30 kg N/ha dose. Measurements were carried out with the involvement of the Renfor early (FAO 320) and Fornad (FAO 420) late maturity hybrids-
The stomata of the plants became more and more closed with the progression of the phenological phases; their stomatal conductance decreased. However, the hybrids responded differently to environmental stress. In the case of the Renfor hybrid, the highest conductance (669 mmol/m2-s) was recorded in the V12 phenophase with the 150 kg N/ha treatment. The stomata were more open due to the high turgor pressure, allowing plants to evaporate properly. The plant was in its worst physiological condition on 2nd July, at the time of the appearance of the last leaf in the case of the 120 kg N dose (224 mmol/m2-s). The value measured in the V12 phenophase has already shown that the stomata were closing due to the self-regulating system of the plant. It would have been necessary to dispense irrigation water following the measurement. This confirms the finding that water stress can be prevented by measuring stomatal conductance.
In the case of the Fornad hybrid, stomatal conductance was the highest on 12th June (630 mmol/m2-s) in the 90 kg N/ha treatment and it was the lowest (183 mmol/m2-s) in VT (emergence of the last leaf) phenophase in the 60 kg N/ha treatment. In this case, the appropriate time for applying irrigation water would have been early July, when the conditions for the plants were still adequate. Subsequently, the stomata began to close due to a reduction of the water resources available to them.
There was a significant correlation between soil moisture and stomatal conductance, as well as between temperature and stomatal conductance.
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Investigation of host-specificity of phytopathogenic fungi isolated from woody plants
155-160Views:320Host-specificity is an important characteristic of fungal pathogens. Changing climate could create more appropriate environmental conditions for phytopathogens, thus formerly host-specify fungi could be able to colonize new hosts. Noxious plant pathogen fungi, which can infect several plant species are well-known worldwide. These genera may expand their range of hosts because of the appearance in new geographic areas due to climate change. This new exposure can result in serious problems in agriculture because of the lack of immunity. The susceptibility of apple tree was studied through testing pathogenicity in vitro with species isolated from walnut twigs and nuts, and identified by ITS sequences. Three of four tested species, Botryosphaeria dothidea, Diaporthe eres and Diplodia seriata colonized and necrotized the infected apple branches, while Juglanconis juglandina was not able to infect the twigs. Members of Botryosphaeriaceae were the most virulent, causing the largest lesions in the fastest way. This experiment draws attention to the threat of new host-pathogen connections, which can arise because of the favourable weather conditions and can spread between neighbouring cultures.