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Results 1951 to 1980 of 4099:

Spatial distribution of cabbage root maggot (Delia radicum) and clubroot (Plasmodiophora brassicae) in winter oilseed rape crops in the Czech RepublicOriginal Paper

Vojtěch Hlavjenka, Marek Seidenglanz, Aleš Dufek, Hana Šefrová

Plant Protect. Sci., 2017, 53(3):159-168 | DOI: 10.17221/181/2015-PPS

The amount and spatial distribution of plants afflicted with cabbage root maggot (Delia radicum; CRM) and clubroot (Plasmodiophora brassicae) in winter oilseed rape crops were assessed in the Olomouc region (Northern Moravia, Czech Republic) over the course of 2012-2014. A total of 16 commercial rape fields were included in the assessments. Plants with tumours showed a significantly lower (P < 0.001) level of infestation induced by CRM (24% of plants infested) compared to plants without tumours (37% of plants infested). According to a generalised linear mixed model, plants with thicker hypocotyls are predisposed to significantly higher levels (P < 0.001) of root surface damage induced by CRM. The correlation analysis indicates rather weak or intermediate levels of correlation between the two variables (hypocotyls thickness × root surface damage induced by CRM). Both CRM and clubroot symptomatic plants showed a significant tendency for aggregation in rape crops, but not in all cases. Distributions of CRM and clubroot symptomatic plants were either significantly spatially dissociated or not associated in crops. Ovipositing D. radicum females showed some tendency to avoid zones with higher number of plants infected by P. brassicae. Distributions of CRM and hypocotyl thickness levels were significantly spatially associated in crops in several cases.

Technological and economic evaluation of manure production using an activator of biological transformationOriginal Paper

Petr Šařec, Oldřich Látal, Petr Novák

Res. Agr. Eng., 2017, 63(10):S59-S65 | DOI: 10.17221/50/2017-RAE

The aim of this paper was to verify the effect of the Z'fix (PRP Technologies, France) activator of biological transformation of manure from the viewpoint of the cowshed conditions parameters, produced manure quality, manure application effect on crop yields, and overall economics. Concerning manure production, the application of the Z'fix agent enhanced quality, structure and nutrient content (N total by 23%, P2O5 by 42%, K2O by 17%) in the manure from deep litter housing. Compared to the untreated control, differences in the nutrient content of N total and K2O were statistically significant, NH3 emissions dropped significantly by almost 35%. The economic benefit of manure production with the use of the Z'fix agent demonstrated overall savings at the level of 1,369 CZK/LU/year. The influence of manure produced combined with the PRP Sol application was tested in terms of a boost of crop yield potential of silage maize and of winter wheat. Compared to the control, both crops reached yields higher by 0.7% to 9.8%.

Differences in the susceptibility of codling moth populations to Cydia pomonella granulovirus in the Czech Republic

T. Zichová, V. Falta, F. Kocourek, J. Stará

Hort. Sci. (Prague), 2011, 38(1):21-26 | DOI: 10.17221/26/2010-HORTSCI

The Cydia pomonella granulovirus is a very important agent for the biological control of the codling moth, Cydia pomonella, in both organic and integrated apple and pear production. Three populations of Cydia pomonella originating from three separate areas of the Czech Republic were tested for their susceptibility to Cydia pomonella granulovirus in laboratory bioassays at several concentrations of Cydia pomonella granulovirus. A sensitive laboratory strain was chosen as a control. The larval mortality was checked 14 days after the infection. The mortality of Cydia pomonella larvae was similar in specimens originating from both the wild populations and the laboratory strain. Decreased susceptibility to Cydia pomonella granulovirus was demonstrated neither in samples from locality without Cydia pomonella granulovirus treatment nor from a locality experimentally treated with Cydia pomonella granulovirus for several years during the registration process. However, one population experimentally treated for more than 10 years was partially resistant to Cydia pomonella granulovirus. Based on our findings; the Cydia pomonella granulovirus biopesticides will be efficient due to the high susceptibility of field codling moth populations to Cydia pomonella granulovirus in the Czech Republic.

Successful elimination of PRRS virus from an infected farrow-to-finish herd by vaccinationOriginal Paper

M. Toman, V. Celer, J. Smola

Vet Med - Czech, 2017, 62(10):553-558 | DOI: 10.17221/68/2017-VETMED

Porcine reproductive and respiratory syndrome (PRRS) virus represents a major threat to the swine industry worldwide. This study describes the transmission of a European strain of PRRS-1 to a pig farm leading to the spread of the virus to different age categories of pigs and the development of clinical signs in pregnant sows and piglets. Porcine reproductive and respiratory syndrome aetiology was confirmed by serological tests and by virus isolation and subsequent sequencing. Repeated mass vaccination using modified live virus was used to synchronise the level of PRRS-specific immunity in all age categories of animals and to hinder virus circulation in the herd. Four months after the second mass vaccination, regular modified live virus vaccination of sows and gilts was implemented. Introduction of sentinel animals demonstrated cessation of virus circulation and the success of the control programme.

Impact of logging intensity on stem density, basal area and biodiversity indices five years after logging in a Caspian hardwood forestOriginal Paper

Farshad KEIVAN BEHJOU, Omid GHAFFARZADEH MOLLABASHI

J. For. Sci., 2017, 63(4):167-172 | DOI: 10.17221/103/2016-JFS

The aim of the present study was to analyse the impacts of different logging intensities after five years from logging including non-logged, low (3.4 felled stems per hectare), medium (5.2 felled stems per hectare) and high (7.1 felled stems per hectare) treatments on stem density, basal area, canopy cover, and forest biodiversity indices. The study area was located in northern Iran. Data was collected on a set of 120 circular plots with 5 m radius from both non-logged and logging areas. Stem density, basal area, and percentage of canopy cover were measured. Biodiversity study was done by measuring two diversity indices including Simpson's and Shannon-Wiener's, two richness indices including Margalef's and Menhinick's and two evenness indices including Pielou's and Hill's indices. The results indicated that the treatment with the medium logging intensity was found to cause the highest amount of positive effects on stem density, basal area, and biodiversity indices. It is concluded that harvesting intensity should be limited to a medium level (approximately 5 felled trees per hectare) during each logging operation to improve forest biodiversity indices.

Management of poppy (Papaver somniferum L.) stand height using growth regulatorsOriginal Paper

Tomáš Spitzer, Jan Bílovský

Plant Protect. Sci., 2017, 53(1):55-60 | DOI: 10.17221/24/2016-PPS

The possibility of reduce the length of poppy plants and their risk of lodging by applying selected plant growth regulators and effects on the plant and yield were studied in field experiments during 2010-2012. Statistically significant reduction was achieved only with ethephon (576 g a.i./ha) in all experimental years. In 2010 reduction for metconazole (60 g a.i./ha) was recorded. In 2012, ethephon at rates of 576 and 288 g a.i./ha prevented significantly poppy lodging. The 576 g a.i./ha rate was phytotoxic and decreased yield. The commonly used 576 g a.i./ha rate diminished heights by 16-20 cm in all experimental years and significantly reduced lodging in 2012, but decreased yields in two of the 3 years.

Assessment of sensory quality of calf chops with different fat cover using a specific sensory method by a trained panelFood Analysis, Food Quality and Nutrition

Iñaki Etaio, Pilar F. Gil, Mónica Ojeda, Luis Javier R. Barron, Francisco José Pérez Elortondo

Czech J. Food Sci., 2017, 35(5):392-400 | DOI: 10.17221/276/2016-CJFS

Carcass fat cover is used in many countries as a predictor of meat quality, although studies relating this parameter to sensor y quality of meat are scarce and are mainly based on acceptability or palatability evaluation. The samples of calf chops with three different degrees of carcass fat cover were analysed according to a specific method for sensor y quality assessment. A trained panel evaluated the samples and scored the sensor y quality related to odour, texture, flavour, and persistence. Samples with higher carcass fat cover presented significantly better scores for texture, flavour, and persistence, although not for odour. When calculating global sensor y quality by integrating the cited parameters, significant differences were found between the three fat cover groups. Texture, f lavour, and persistence were also correlated with fat cover and marbling degree. Specific sensor y characteristics (medium tenderness, slightly tough, rancid odour, cooked meat aroma, equal or higher than fat aroma, ver y low aroma intensity, dominance of fat aroma, obvious liver aroma and milky aroma) contributed to explaining the quality differences obser ved among the groups.

Application of the chlorophyll fluorescence ratio in evaluation of paddy rice nitrogen statusOriginal Paper

Jian YANG, Lin DU, Wei GONG, Jia SUN, Shuo SHI, Biwu CHEN

Plant Soil Environ., 2017, 63(9):396-401 | DOI: 10.17221/460/2017-PSE

In this research, laser-induced fluorescence (LIF) technique combined with back-propagation neural network (BPNN) was employed to analyse different nitrogen (N) fertilization levels in paddy rice. Leaf fluorescence characteristics (FLCs) were measured by using the LIF system built in our laboratory and exhibited different FLCs with different nitrogen fertilization levels. The correlation between fluorescence intensity ratios (F685/F460, F735/F460 and F735/F685) and the dose of N fertilization was established and analysed. Then, the BPNN algorithm was utilized to validate that the different N fertilization levels can be classified based on the three FLCs. The overall identification accuracies of 2014 and 2015 were 90% and 92.5%, respectively. Experimental results demonstrated that the three FLCs with the help of multivariate analysis can be served as a helpful tool in the evaluation of paddy rice N fertilization levels. Besides, this study can also provide guidance for the selection of LIF Lidar channels in the following research.

Investigation of locust bean husk char adsorbability in heavy metal removalOriginal Paper

Ademola Ajayi-Banji, Ayo Ogunlela, Gbolabo Ogunwande

Res. Agr. Eng., 2017, 63(1):29-35 | DOI: 10.17221/44/2015-RAE

he column adsorption study examines irrigation water treatment prior to its application in order to ensure water-crop-consumer heavy metal transfer reduction to the safe level using locust bean husk char (LBHC) as biosorbent. Char structural pattern was investigated with SEM-EDX machine. Contaminated surface water was introduced simultaneously into the bioreactors containing 100 and 200 g of LBHC and collected after 30, 60, 90 120 and 150 min of detention time. Removal efficiency, isotherm and kinetic sorption model were the evaluation tools for the study. Percent of Cr, Cd and As removal at 150 min retention time were 83.33, 100 and 100%, respectively for 100 g biosorbents. A similar trend was observed for Cr and As removal at the same retention time for 200 g of LBHC. Metals sorption conforms to the Freundlich isotherm with correlation coefficient values greater than 0.92. Experimental kinetics had a good fit for pseudo second order (R2 > 0.94 for most cases). Removal efficiency is a function of contact time, biosorbent dosage and metal concerned. Locust bean husk char has good and effective treatability for some heavy metals in mildly polluted water.

The transactions on the agricultural land market in SlovakiaOriginal Paper

Štefan BUDAY, Tatiana ČIČOVÁ

Agric. Econ. - Czech, 2014, 60(10):449-457 | DOI: 10.17221/56/2014-AGRICECON

Data on the transactions with agricultural land in 2012, based on the primary data from the Research Institute of Geodesy and Cartography in Bratislava, were evaluated according to the legal status of the buyer and also whether the legal person was a national of the Slovak Republic, or had been resident abroad. The results of the data analysis pointed out that in the selected twelve districts of the Slovak Republic in 2012, there were 55.75% of legal persons, 44.10% of natural persons and 0.15% of subjects without determining the legal form involved in the transactions with agricultural land. Legal persons were divided into two categories, i.e. the entities with the nationality of the Slovak Republic and the entities domiciled abroad. The results showed that in 2012, within the study sample of buyers of the farmland, there were 99.91% of legal persons having the nationality of the Slovak Republic, and only 0.09% was other legal persons from abroad.

Phosphorus loss potential and phosphatase activities in paddy soilsOriginal Paper

S. Wang, X. Liang, G. Liu, H. Li, X. Liu, F. Fan, W. Xia, P. Wang, Y. Ye, L. Li, Z. Liu, J. Zhu

Plant Soil Environ., 2013, 59(11):530-536 | DOI: 10.17221/626/2013-PSE

The effects of phosphorus (P) fertilizer on P loss potential, soil Olsen-P and neutral phosphatase activities in paddy soils fertilized with superphosphate or pig manure (PM) were evaluated in this paper. Data were collected from a field experiment in the Tai Lake Basin, China. Superphosphate rates were 0, 17.5, 26.7, and 35.0 kg P/ha, and PM rates were 0, 1.4, 2.1, and 2.8 t/ha for each crop, respectively. Soil Olsen-P in the plow layer increased to a greater extent with PM than with superphosphate. Pig manure increased neutral phosphatase activities in the plow layer compared with PM-free treatment. In contrast, superphosphate inhibited neutral phosphatase activities compared with superphosphate-free treatment. Spring application of P fertilizer markedly increased the total P of surface water in November (< 0.01 vs. 0.10 mg/L) compared with P-free treatment. The total P of shallow groundwater at a 75 cm depth was ~0.01 mg/L. Phosphorus fertilizer did not influence Olsen-P or neutral phosphatase activities under the plow layer. Downward movement of P did not occur. Appropriate rate of P application of 26.2 kg P/ha for each crop in this soil reduced the risk of P loss in the paddy wetland ecosystem.

Inclusion of yeast-derived protein in weanling diet improves growth performance, intestinal health, and anti-oxidative capability of pigletsOriginal Paper

L. Hu, L. Che, G. Su, Y. Xuan, G. Luo, F. Han, Y. Wu, G. Tian, C. Wu, Z. Fang, Y. Lin, S. Xu, D. Wu

Czech J. Anim. Sci., 2014, 59(7):327-336 | DOI: 10.17221/7531-CJAS

The effects of yeast-derived protein (YP) on growth performance, intestinal health, and oxidative status of weanling piglets were investigated. A total of 80 weaned piglets (PIC 327 × 1050, 26 ± 2 days old, 6.20 ± 0.10 kg) were randomly allocated into 2 groups, 5 pens per each group and 8 piglets per each pen, receiving control diet and diet with inclusion of 4% YP at the expenses of fish meal (YP diet) for a period of 28 days. The diets were formulated to contain similar nutrient levels. Compared with control, piglets fed YP diet had markedly higher overall average daily growth (+14%, P < 0.05) and lower final feed conversion ratio (-8%, P < 0.01). Concentrations of serum serine, cystathionine, histidine, hydroxyproline, and urea were decreased in piglets fed YP diet (P < 0.05), whereas alanine and aspartate were increased (P < 0.01). Moreover, serum antioxidant enzyme activity (glutathione peroxidase) was markedly increased (+19%, P < 0.01) in piglets fed YP diet relative to piglets fed control diet. In addition, feeding YP diet considerably (P < 0.05) increased the copy numbers of lactobacilli and total bacteria in the colon of piglets at the end of the experiment. Furthermore, the mRNA abundance of innate immunity-related genes (TLR4, NF-κB1, and IL-6) was increased (P < 0.06) in the ileum of piglets fed YP diet. Collectively, results of this study indicated that diet with the inclusion of YP improved growth performance and partially enhanced anti-oxidative capability as well as intestinal innate immunity of weaning piglets.

Influence of the origin on selected determinants of the quality of pork meat productsOriginal Paper

Bożena GARBOWSKA, Monika RADZYMIŃSKA, Dominika JAKUBOWSKA

Czech J. Food Sci., 2013, 31(6):547-552 | DOI: 10.17221/479/2012-CJFS

in recent years, great attention has been paid to the quality of eaten meat and its products. There have been launched a lot of promotional campaigns aimed at providing opportunities for the consumption of traditional products. Based on the experiment, a significantly higher protein content was found in sausages produced by large producers (24.73 ± 1.98%). The fat content was significantly higher in traditional ham (16.25 ± 14.47%), compared with local ham (4.38 ± 2.26%) and the mass (9.29 ± 5.25%). The samples of traditional and local ham had a significantly higher salt content (3.31 ± 0.72 and 2.90 ± 0.54%, respectively). No dye compounds were detected in any of the tested samples. There were no statistically significant differences in hydroxyproline and l‑glutamic acid content between traditional and conventional samples of meat products. Analysis of nitrate (V and III) showed a statistically significant difference in the average contents of these compounds. Significantly higher levels of nitrates were revealed only in traditional ham samples (12.60 ± 8.08 mg NaNO(V)/kg and 17.53 ± 27.91 mg NaNO(III)/kg of the product, respectively), wherein there was a large variation in the content of these compounds in the samples.

Effect of housing system and genotype on rabbit meat qualityOriginal Paper

D. Chodová, E. Tůmová, M. Martinec, Z. Bízková, V. Skřivanová, Z. Volek, L. Zita

Czech J. Anim. Sci., 2014, 59(4):190-199 | DOI: 10.17221/7343-CJAS

The effect of the housing system on the carcass characteristics, physical parameters of meat quality, fatty acid composition, and muscle fibre characteristics was studied in some Czech breeds. Ninety-six rabbits from seven different breeds of Czech genetic resources (Moravian Blue, Czech White, Czech Solver, Czech Spotted, Moravian White of Brown Eye, Czech Gold, and Czech Black Guard Hair) and one rabbit commercial hybrid (Hyplus), kept in two housing systems: intensive system (wire-net cages) or alternative (straw-bedded pen), were slaughtered at the age of 91 days. Alternatively housed rabbits had lower weight at slaughter, lower weight of loin, of hind legs meat, and of renal fat than rabbits from cages. The interactions between housing system and genotype were reflected significantly in pH value, and lightness and yellowness of biceps femoris. The highest (P ≤ 0.047) pH was observed in Hyplus (6.68) from cages, while the lowest value was noted in Moravian White of Brown Eye (6.26). The significantly (P ≤ 0.010) lightest meat was detected in Czech Solver (60.93) and the darkest in Czech Gold (47.81). Alternatively reared rabbits showed significantly (P ≤ 0.001) lower monounsaturated fatty acids (MUFA) (26.63%) and higher (P ≤ 0.001) polyunsaturated fatty acids (PUFA) (36.73%) contents than rabbits from cages (36.94% MUFA and 26.23% PUFA). The alternatively housed group had also higher n-3 and n-6 PUFA contents and higher PUFA : SFA ratio than the intensively housed one. Significant interactions (P ≤ 0.001) were observed in cross sectional area (CSA), diameter, and perimeter of muscle fibres of type I. The largest (P ≤ 0.001) CSA of type I muscle fibre had Czech Black Guard Hair from cages (2573.1 μm2), while in pens this breed exhibited the smallest CSA (1219.6 μm2), diameter (38.68 μm), and perimeter (130.2 μm). Fibre type distribution was not affected by any of the monitored parameters. The effect of interactions of the housing system and genotype was manifested mainly in physical and muscle fibre characteristics.

Photosynthesis sensitivity to NH4+-N change with nitrogen fertilizer typeOriginal Paper

A. Nasraoui-Hajaji, H. Gouia

Plant Soil Environ., 2014, 60(6):274-279 | DOI: 10.17221/7418-PSE

N-fertilization type affected differently tomato growth. In the field experiment, hydroponic cultures were conducted using NO3-N (5 mmol); mixture of KNO3-N (3 mmol) and (NH4)2SO4-N (2 mmol); NH4+-N (5 mmol) or urea (5 mmol) as nitrogen source. Compared to nitrate, ammonium and urea had negative effects on morphology and dry matter production. Effects of the different nitrogen forms were investigated by measuring several photosynthesis parameters and chl a fluorescence. Two different significant types of reaction were found. When nitrogen was added as ammonium or urea, dry weight, chlorophyll tenor, transpiration rate, stomatal conductance and photosynthetic activity were inhibited. Supply of ammonium or urea, reduced the ratio (Fv/Fm), photochemical quenching and enhanced the non photochemical quenching. These data suggest that the adverse decrease in tomato growth under ammonium or urea supply may be related principally to inhibition of net photosynthesis activity. The high non photochemical quenching shown in tomato fed with ammonium or urea indicated that PS II was the inhibitory site of NH4+-N which was directly uptaken by roots, or librated via urea hydrolysis cycle.

Nutritive value of red clover and lucerne forages for ruminants estimated by in vitro and in vivo digestibility methods

P. Homolka, V. Koukolová, M. Podsedníček, A. Hlaváčková

Czech J. Anim. Sci., 2012, 57(10):454-468 | DOI: 10.17221/6346-CJAS

The aim of this study was to determine the nutrient and energy levels of red clover and lucerne forage. Investigation of forage at different maturity stages of three growths was carried out by chemical analysis, in vitro and in vivo digestibility methods. Generally, maturation caused a significant increase in fibre fractions. With the increasing maturity of forage samples the in vivo, in vitro, and calculated in vivo (in vivocalcul) digestibilities of organic matter (OM) linearly decreased. The in vitro and in vivocalcul digestibilities of OM averaged 0.754 and 0.708 for red clover and 0.717 and 0.667 for lucerne, respectively. The in vivo OM digestibility averaged 0.710 for red clover and 0.666 for lucerne. Gross energy (GE), digestible energy (DE), metabolizable energy (ME), net energy for lactation (NEL), and net energy for growth (NEG) averaged 18.12, 12.41, 9.60, 5.67, 5.50 and 18.09, 11.56, 9.01, 5.26, 4.99 MJ/kg of dry matter for red clover and lucerne, respectively. The effect of a vegetative stage on energy values of both forages was diverged for various growth times. When data were pooled across the estimated season, seven cutting-specific equations for descriptions of GE, DE, ME, NEL, NEG, in vitro, and in vivo OM digestibilities were obtained for red clover and lucerne, separately. The red clover model expression gave similar prediction equations for lucerne. It was possible to predict cutting-specific equations with coefficients of determination R2 > 0.719 for red clover and R2 > 0.400 for lucerne of the variation in GE, DE, ME, NEL, and NEG. The in vitro and in vivo OM digestibility equations were predicted with R2 being 0.840 (in vitro) and 0.707 (in vivo) for red clover, and 0.979 (in vitro) and 0.937 (in vivo) for lucerne. The parameters of these specific equations were statistically preferable than the general model expression which included both forages together.

Enzymatically hydrolysed molasses and sodium citrate as new potentials for the improvement of canthaxanthin batch synthesis by Dietzia natronolimnaea HS-1: A statistical media optimisationOriginal Paper

Seyed Mohammad Taghi Gharibzahedi, Seyed Hadi Razavi, Mohammad Mousavi

Czech J. Food Sci., 2014, 32(4):326-336 | DOI: 10.17221/472/2013-CJFS

Response surface methodology-central composite rotatable design (RSM-CCRD) was applied to explore the optimum media formulation for maximising canthaxanthin (CTX) biosynthesis by Dietzia natronolimnaea HS-1. The effects of three variables of enzymatically hydrolysed molasses (EHM) (16.6-33.4 g/l), sodium (Na)-citrate (21.64-28.36mM), and yeast extract (6.32-9.68 g/l) concentrations on the production of CTX, total carotenoid (TCT), and biomass dry weight (BDW) were appraised. The results showed that the quadratic effects of EHM, yeast extract, and Na-citrate contents in terms of second-order polynomial regression equations (R2 = 0.968-0.986), respectively, had the most significant effects on the produced TCT and CTX. The predicted maximum accumulation of BDW (8.88 g/l), TCT (7.24 mg/l), and CTX (6.40 mg/l) under the optimum concentrations of the media variables (26.16 g/l EHM, 8.29 g/l yeast extract, and 25.86mM Na-citrate) was very close to the experimental values determined in batch experiments. The high BDW content suggested EHM and Na-citrate as very promising feedstocks for CTX bioproduction by the bacterium studied.

Effects of pre- and postharvest factors on browning in BraeburnOriginal Paper

D. Hatoum, K. Buts, M.L.A.T.M. Hertog, A.H. Geeraerd, A. Schenk, J. Vercammen, B.M. Nicolai

Hort. Sci. (Prague), 2014, 41(1):19-26 | DOI: 10.17221/180/2013-HORTSCI

The effects of several pre- and postharvest factors on apple cv. Braeburn browning disorder (BBD) incidence using a nine-factor experimental design has been investigated. The design allowed the determination of the effects of single factors as well as their interaction with growing season and storage time. BBD increased in severity with storage duration. BBD incidence was reduced with calcium and potassium fertilizers application, while it was increased when triazoles were used. Delayed controlled atmosphere (DCA) application resulted in less BBD in storage, while treatment with 1-methylcyclopropene (1-MCP) increased BBD incidence. More BBD was observed in fruit stored at above optimal CO2 levels. BBD incidence was increased when O2 concentration in CA was increased from 1 kPa to 3 kPa (optimum CA) or 6 kPa. Finally, the various factors showed a different effect for different growing seasons and storage time. These findings suggest a possible mechanism for the development of BBD. Further work should focus on extending the experimental design to include the interactions between the different pre- and postharvest factors.

Factors affecting the development of Phytophthora alni ssp. alni infections in Alnus glutinosa L.

P. Štochlová, K. Novotná, K. Černý

J. For. Sci., 2012, 58(3):123-130 | DOI: 10.17221/26/2011-JFS

Phytophthora alni is responsible for a devastating disease in alder and changes in the environment of riparian and alder carr ecosystems. One of the main approaches to solve this problem is to find naturally resistant genotypes using a series of artificial inoculation experiments, to preserve and use them in programmes for resistance breeding. However, the results of artificial inoculation experiments (screening for natural resistance) can be affected by several factors. The potential effect of the social status of the host, the presence of naturally occurring P. alni infections, the season and the size of the sections of branches used were studied in a series of infection experiments. It was found out that the development of lesions was significantly affected by the year season (the largest lesions were found in summer) and by the presence of naturally occurring P. alni infections in the sampled trees (the lesions were five times larger in healthy trees and trees recovered from natural P. alni infections compared to trees with active disease development).

Antioxidant potential of spinach, peas and sweet corn in relation to freezing periodOriginal Paper

Daniel BAJČAN, Ján TOMÁŠ, Gabriela UHLÍŘOVÁ, Július ÁRVAY, Pavol TREBICHALSKÝ, Radovan STANOVIČ, Vladimír ŠIMANSKÝ

Czech J. Food Sci., 2013, 31(6):613-618 | DOI: 10.17221/529/2012-CJFS

We evaluated changes in the content of total polyphenols and antioxidant activity of frozen spinach, peas, and sweet corn in relation to the storage period. Total polyphenol content and antioxidant activity in analysed samples were determined by colorimetric methods. Both parameters were analysed in frozen samples monthly and the changes were monitored during storage in a freezing box at a temperature of -18°C for 10 months. Freezing had a different influence on the levels of total polyphenol content and antioxidant activity in individual analysed samples. The greatest decrease in antioxidant activity during the entire period of freezing was recorded in spinach (79.4%), while the lowest decrease was observed in peas (26.8%). A relatively significant decrease in antioxidant activity was also found in sweet corn (62.7%). On the contrary, the greatest decrease of total polyphenol content throughout the period of freezing was found in peas (62.0%), and lowest decrease was recorded in sweet corn (only 5.0%). The total polyphenol content in spinach decreased by 43.1% after 10 months of storage.

The influence of whey, whey component and malt on the growth and acids production of lactobacilli in milkOriginal Paper

Šárka HORÁČKOVÁ, Pavla SEDLÁČKOVÁ, Marcela SLUKOVÁ, Milada PLOCKOVÁ

Czech J. Food Sci., 2014, 32(6):526-531 | DOI: 10.17221/214/2014-CJFS

The effect of whey powder, whey protein concentrate, caseinomacropeptide, and malt addition into milk on the growth and acid production of lactobacilli (Lactobacillus casei Lafti L-26, Lactobacillus acidophilus CCDM 151, and Lactobacillus casei CCDM 198) was evaluated. The ability of these strains to use different types of saccharides from milk and plant sources was also tested. Glucose, galactose, fructose and maltose were utilised by all tested strains. The results showed that the addition of malt positively affected the growth of lactobacilli strains compared to the growth in milk enriched by whey ingredients. The addition of malt increased significantly the production of d(-)isomer of lactic acid by Lactobacillus acidophilus CCDM 151 and Lactobacillus casei CCDM 198 and the production of acetic acid by Lactobacillus casei CCDM 198.

Amelioration of salt affected soils in rice paddy system by application of organic and inorganic amendmentsOriginal Paper

M. Shaaban, M. Abid, R.A.I. Abou-Shanab

Plant Soil Environ., 2013, 59(5):227-233 | DOI: 10.17221/881/2012-PSE

Combined application of organic and inorganic amendments was known to play a significant role in improvement of soil properties. A field experiment was conducted to explore the effects of gypsum, farmyard manure and commercial humic acid application on the amelioration of salt affected (saline sodic) soil. During this study, soil pH, electrical conductivity, sodium adsorption ratio, responses of root length and rice paddy yield were examined. Application of gypsum with or without farm manure and commercial humic acid decreased soil pH (8.26%), electrical conductivity (from 6.35 dS/m to 2.65 dS/m) and sodium adsorption ratio (from 26.56 to 11.60), and increased root length (from 9.17 cm to 22.6 cm) and paddy yield (from 695.7 kg/ha to 1644 kg/ha). A negative but significant correlation was observed between root length and electrical conductivity, sodium adsorption ratio (r = -0.93; -0.94, respectively, P ≤ 0.05), whereas positive and significant correlation with paddy yield (r = 0.96; P ≤ 0.05).

Preying capacity of different established predators of the aphid Lipaphis erysimi (Kalt.) infesting rapeseed-mustard crop in laboratory conditionsOriginal Paper

Kuldeep SINGH, Narendra N. SINGH

Plant Protect. Sci., 2013, 49(2):84-88 | DOI: 10.17221/66/2011-PPS

Experiments on the preying capability of different stages of larvae of coccinellid and syrphid flies on the mustard aphid, Lipaphis erysimi (Kalt.), were conducted in a laboratory during the winter cropping seasons of 2009-2010 and 2010-2011. Results revealed that grubs of the Coccinella septempunctata Linn. preyed the highest number of mustard aphids (average 61.42 aphids/day) followed by Syrphus confrater Wied (34.81 aphids/day), Syrphus balteatus Deg. (32.26 aphids/day) and Ischiodon scutellaris Fab. (27.76 aphids/day) during their larval span. Among the larval stages of the coccinellid and syrphid predators, it was also analysed that the last juvenile stage of the predators was proved the mightiest devourer against the aphid L. erysimi. These predators could be used effectively for the management of L. erysimi on rapeseed-mustard crop.

Structure of 0+ juvenile fish assemblages in the modified upper stretch of the River Elbe, Czech RepublicOriginal Paper

Z. Valová, M. Janáč, J. Švanyga, P. Jurajda

Czech J. Anim. Sci., 2014, 59(1):35-44 | DOI: 10.17221/7192-CJAS

In August 2007, the 0+ juvenile fish assemblage of the upper River Elbe was surveyed using electrofishing. Thirty-six localities were sampled along a 177 km long section between the towns of Verdek and Brandýs nad Labem (river km (RKM) 136-313). Four localities with natural riverbeds, 14 channelized stretches, nine beaches, and nine backwaters were sampled. Altogether, 4521 0+ juvenile fishes were caught, belonging to 26 species. A decrease in species richness and abundance was evident near Hradec Králové, while decreased species abundance was noted along the navigated stretch below Přelouč. The highest catch-per-unit-effort (CPUE), species richness, and Shannon index values were observed at beach habitats, the lowest in channelized habitats, and intermediate values in backwaters. Generally, rare beach habitats had significantly more rheophilic species than other habitats, while backwaters had significantly more eurytopic species and higher CPUE for limnophilic species. Backwaters and channel habitats, however, did not differ in any other 0+ fish assemblage parameter studied. The study demonstrated the importance of beaches for fish assemblages along navigable channels. Surprisingly, however, backwaters were not confirmed as important nursery habitats.

Technical exploitation parameters of grinding rolls work in flour millOriginal Paper

R. Opáth

Res. Agr. Eng., 2014, 60(10):S92-S97 | DOI: 10.17221/41/2013-RAE

The proposed research paper analyses power consumption in grinding rolls of a flour mill. The observed mill has 15 grinding passages. The hourly efficiency of grinding roll on the first passage is 3,006.72 kg/h. The specific power consumption of individual grinding rolls ranges from 4.955 to 24.26 kWh/t. The thesis also contains results of research of grinding effects on grist. The greatest effect on grist was observed on the first grinding passage, where particle size after grinding was only 12% of the original grain size, as determined by sieve analysis. On the second through fifth passage, it was 85 to 96% (or 78 to 85% with shelling) of the original size. It was discovered during scouring that, in some cases, the sieve size of particles after grinding increased from 101 to 104% of the original size. This is due to shear force causing trituration of grist.

Evaluation of the variability in runoff and sediment loss in successional fallow vegetation of Southern NigeriaOriginal Paper

Anthony I. IWARA

Soil & Water Res., 2014, 9(2):77-82 | DOI: 10.17221/27/2013-SWR

The effects of three different ages of natural fallow vegetation on runoff and sediment loss were investigated in a part of the rainforest zone of Nigeria. Measurements of runoff amount and sediment loss were made for the months of March to November in 2012 rainy season using runoff plots of 40 m2. The average runoff amount for the 5-year-old, 3-year-old, and farmland plots were 0.47, 0.26, and 0.41 mm respectively. The average sediment loss on the 5-year-old, 3-year-old, and farmland plots were 209.24, 50.54, and 124.68 kg/ha, respectively. The lowest losses for both runoff and sediment were recorded on the 3-year-old plot, while the 5-year-old plot experienced the highest losses. The variations in runoff and sediment loss among the treatments were significant at P < 0.001. The results evidently showed that rainfall was principally responsible for the erosional losses on all the fallow treatments, and that ground cover (density of herbs) and girth helped to reduce sediment loss on the 3-year-old and farmland surfaces, respectively. The high amount of erosional losses experienced on the 5-year-old fallow than on the 3-year-old fallow and farmland plots imply that fallow that is not adequately protected by ground cover experiences accelerated soil erosion. The continuous loss in topsoil rich in plant nutrients may prolong the optimal capacity of the soil to regain its loss nutrient for subsequent food crop cultivation.

Effect of Oriental beech root reinforcement on slope stability (Hyrcanian Forest, Iran)Original Paper

E. Abdi

J. For. Sci., 2014, 60(4):166-173 | DOI: 10.17221/93/2013-JFS

Vegetation significantly affects hillslope mechanical properties related to shallow landslides and slope stability. The objective of this study was to investigate and quantify the effect of Oriental beech root reinforcement on slope stability. A part of Hyrcanian forest in northern Iran was selected for the study area. To do the research, the Wu model (WM) was used and data related to the distribution and tensile strength of Oriental beech roots were collected. Root distribution was assessed using the concept of the root area ratio and trenching method. Laboratory tensile tests were conducted on fresh roots for strength characteristics. The factor of safety was calculated for two different soil thicknesses (1 and 2 m) and slope gradients between 10 and 45°. The results showed that the root distribution generally decreased with increasing soil depth and the mean root strength value was 38.23 ± 1.19 MPa for 0.35-5.60 mm diameter range. The results verified a power relationship between tensile strength and root diameter. The reinforcement effect (Cr) decreased with depth and the strongest reinforcement effect was in the second soil layer (10-20 cm) which showed a shear strength increase of 1.47 kPa. The increased factor of safety due to the presence of roots in one- and two-metre soil thicknesses was 27-44% and 15-26%, respectively. The improvement effect of roots was increased with increasing slope gradient and shallower soil thicknesses.

Nutritional and sensory value of conventionally vs organically grown Chinese radish (Raphanus sativus L. var. longipinnatus)Original Paper

M. Jurica, K. Petříková

Hort. Sci. (Prague), 2014, 41(2):64-70 | DOI: 10.17221/200/2013-HORTSCI

The nutritional and sensory value of Chinese radish, cv. Jarola F1, grown in organic and conventional systems was evaluated. The experiments were based on certified organic land and conventional land of the Czech University of Life Sciences Prague at the experimental station of Troja. Radish was grown in two spacings. Radish from the organic cultivation system exhibited a significantly lower dry matter content compared to the conventional production, 62.4 g/kg and 68.9 g/kg, respectively. This can be explained by growing under unwoven textile. Furthermore, radish cultivated organically had a significantly lower content of monosaccharides (17.2 mg/kg, while the conventional production contained 26.1 mg/kg) and significantly higher contents of nitrates. The content of vitamin C in organic production tended to be higher (212 mg/kg, in conventional production 169 mg/kg). The crude fibre content or the content of minerals was not significantly affected by the growing system. Growing spacing did not affect the nutritional value. Organically produced radish had better sensorial evaluation.

Chemical induction of haploid gynogenesis in sterlet Acipenser ruthenus Original Paper

I. Lebeda, I. Gazo, M. Flajshans

Czech J. Anim. Sci., 2014, 59(7):310-326 | DOI: 10.17221/7530-CJAS

Chromosomal manipulations in sturgeons, particularly gynogenesis, are interesting due to the potential to change female ratio in progeny that can be useful for caviar production. The optimization of UV treatment for induction of gynogenesis is complicated due to high and variable optical density of the milt due to differential spermatozoa concentration, and because of sensitivity of spermatozoa's motility apparatus. Therefore in this study we compared chemical methods of sperm treatment as an alternative to short wave-length UV treatment; evaluation considers impact on spermatozoa motility, DNA integrity, and efficiency of DNA inactivation. Dimethyl sulfate (DMS) in concentrations of 2.5-30mM was applied to spermatozoa in order to inactivate DNA. Also ethidium bromide (EB), psoralen (PS), and 4'-aminomethyl-4,5',8-trimethylpsoralen (AMT) were used to increase sensitivity of spermatozoa's DNA to long wavelength UV-A light (360 nm). CASA analyses of treated sperm showed strong negative effects on spermatozoa motility with the increasing concentration of active substances. Additionally in case of PS, EB, and DMS treatment comet assay did not reveal significant DNA damage of sperm at the range of concentrations relatively safe for spermatozoa motility. Flow cytometric analysis of relative DNA content in larvae resulting from activation of normal ova of sterlet with the treated sperm showed low efficiency of haploid gynogenesis induction. The putative gynogenetic larvae were found after treatment with PS in concentrations higher than 18µM and EB higher than 10µM followed by UV-A irradiation at the dose of 900 J/m2 and DMS up to 5mM. Because of an overwhelming impact on the sperm motility and relatively low DNA damage, treatment of sperm with PS, EB or DMS did not prove efficient compared with a widely used UV-C irradiation treatment. In contrast, treatment with AMT followed by UV-A showed lower influence on spermatozoa motility and higher efficiency of DNA damaging resulting in the higher percentage of gynogenotes in the progeny, thus could be considered as a possible substitution for UV-C treatment.

Effect of drying method on the phenolic content and antioxidant capacity of spearmintOriginal Paper

Antia Orphanides, Vlasios Goulas, Vassilis Gekas

Czech J. Food Sci., 2013, 31(5):509-513 | DOI: 10.17221/526/2012-CJFS

The changes in total phenolics, hydroxycinammic acid derivatives, and antioxidant properties of spearmint after five drying treatments (convection oven drying, freeze-drying, microwave drying, and air drying with the sun exposure and without the sun exposure) were investigated. Phenolic composition of dried spearmint was analysed by spectrophotometric assays, while DPPH radical scavenging activity and Ferric reducing/Antioxidant power (FRAP) assay was used to measure the antioxidant properties. The results showed that freeze drying produced dried spearmint that had the highest total phenolics (34.6 ± 1.9 mg/g) content and the most potent antioxidant capacity (126.2 ± 0.4 mg/g for FRAP and 88.1 ± 5.9 mg/g for DPPH, respectively). On the other hand, spearmint that was dried by convection oven and microwave drying presented the lowest amount of phenolic compounds (12.0 ± 0.5 mg/g) and antioxidant potency (49.3 ± 0.7 mg/g for FRAP and 26.9 ± 1.6 mg/g for DPPH, respectively). This might be attributed to the fact that heat-sensitive phenolics were degraded or biotransformed at high temperatures. The loss of phenolic compounds and antioxidant activity reached up to 60% compared to freeze drying.

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