scholarly journals Virulence analyses of the powdery mildew population on wheat in the CzechRepublic in 1995–1998

1999 ◽  
Vol 35 (No. 2) ◽  
pp. 57-62
Author(s):  
K. Klem
Keyword(s):  
Czech Republic ◽  
Powdery Mildew ◽  
Blumeria Graminis ◽  
Spore Trap ◽  
Gametic Disequilibrium ◽  
The Czech Republic ◽  
High Frequencies ◽  
B Values ◽  
One Year ◽  
Virulence Frequency

In 1995–1998, the frequency of selected virulences in the powdery mildew ( Blumeria graminis f. sp. tritici ) population on wheat in the Czech Republic was investigated. Samples of conidia were collected by a mobile version of a spore-trap. A total of 1739 one-colony isolates were analysed on a set of five varieties as differentials. High frequencies (> 50%)  were found for virulences Vm2, Vm3a, Vm5 and Vml7, lower frequencies(< 50%) for combinations Vm9,2,1 and Vm2,6 and for Vm4b. There were no significant changes in virulence frequencies except for genes Vm5 and Vm9,2,1 that showed one-year variations. Differences between the eastern part (Moravia) and western part (Bohemia) of the Czech Republic were mostly insignificant for most exam­ ined genes. A significantly higher virulence frequency was found in Moravia for genes Vm3a (in 1995) and Vml7 (in 1996), and in Bohemia for the combination Vm9,2,1 (in 1995). A significant correlation (tested by Kendall's tau B values) existed between Vm2 and Vm5 in 1997 and 1998, and between Vm4b and Vm5 in 1995 and 1998. Values of gametic disequilibrium were also studied. Changes in the complexity of isolate virulence were determined to be small and showed no definite trend.  

scholarly journals Virulence and Diversity of Blumeria graminis f. sp. hordei in Israel and in the Czech Republic

Plant Disease ◽  
2006 ◽  
Vol 90 (8) ◽  
pp. 1031-1038 ◽  
Author(s):  
Antonín Dreiseitl ◽  
Amos Dinoor ◽  
Evsey Kosman
Keyword(s):  
Czech Republic ◽  
Hordeum Vulgare ◽  
Wild Barley ◽  
Natural Populations ◽  
Blumeria Graminis ◽  
The Czech Republic ◽  
Virulence Frequency

Three hundred and nine isolates were obtained from three natural populations of Blumeria graminis f. sp. hordei occurring on wild barley (Hordeum vulgare subsp. spontaneum) at two locations in Israel during 1997 and 1999. Their virulence frequency was determined on 32 differential lines. No isolate was virulent on the differential lines possessing the genes Mla13, mlo, Mlf1, and Mli, and conversely no isolate was avirulent on the differential lines possessing the genes MlRu2, MlLa, Mlh, Mla8, Mla25, and Mlj. The frequencies of isolates overcoming the genes Mlg, Mla7, and Mla27 were 0 to 16% at individual locations; frequencies of isolates overcoming the genes Mla9, Mla17, and Mla18 ranged from 37 to 78%, and frequencies of virulences to genes Mla1, Mla3, Mla6, Mlp1, Mlat, Mla12, Mlra, Mlk1, Mla19, Mla20, Mla26, Mla28, Mla29, Mla30, Mla32, and mlt1 were 79 to 99%. Based on examination of 376 isolates collected in the same years from the Czech Republic, these populations differed greatly from the Israeli ones. The Czech populations showed greater diversity of virulence and lower mean virulence complexity than the Israeli populations. Diversity in the Israeli populations differed also among clusters of niches at the same location.

scholarly journals Changes in the population of Blumeria graminis f.sp. hordei in the Czech Republic from 2009 to 2010

2012 ◽  
Vol 47 (No. 2) ◽  
pp. 43-51 ◽  
Author(s):  
A. Dreiseitl
Keyword(s):  
Czech Republic ◽  
Powdery Mildew ◽  
Spring Barley ◽  
Blumeria Graminis ◽  
The Czech Republic ◽  
Barley Cultivars ◽  
Wide Range ◽  
Pathogen Populations

Virulences to powdery mildew resistances in barley cultivars mostly carrying unknown resistances were determined in 2009 and 2010. Random spore samples of the airborne pathogen populations originating from winter and spring barley fields were obtained by means of a mobile version of a jet spore sampler by travelling across theCzech Republic. In total 301 isolates were studied, 55 differentials carrying mostly unknown resistances were used and 80 pathotypes were found, of which 26 representing 73.1% of isolates were detected in both years. Virulence frequencies showed a wide range from 0% to 100%. Complexity of the 2010 population slightly increased, mostly due to increasing frequencies of virulence to new resistances, whereas the complexity of virulences to resistances in most other differentials decreased. Pathotype 00027 was the most abundant (10.0%). Diversity of the 2010 population  considerably increased due to changes in virulence frequencies.

scholarly journals Evaluation of gooseberry cultivars resistance to the American gooseberry powdery mildew Sphaerotheca mors uvae Schwein and its chemical control

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 583-587
Author(s):  
M. Vaverka ◽  
S. Vaverka
Keyword(s):  
Biological Activity ◽  
Czech Republic ◽  
Powdery Mildew ◽  
Chemical Control ◽  
Biological Effect ◽  
Field Trials ◽  
The Czech Republic ◽  
Biological Efficacy ◽  
Extensive Field ◽  
Susceptibility Evaluation

In the course of 1993–2001 extensive field trials were carried out to evaluate the resistance (susceptibility) level of 34 gooseberry cultivars to the American gooseberry powdery mildew Sphaerotheca mors uvae Schwein. Cultivars originated from the Czech Republic and from other European countries. Each tested cultivar had 7 trees (5–10 years old). Beside the resistance (susceptibility) evaluation, biological efficacy of 9 fungicides using EPPO methods has been checked at the same number of cultivars and at the same number of gooseberry trees. Highly significant differences of resistance or susceptibility were observed among gooseberry varieties. Analogical results (differences in biological activity of fungicides) have been attained in the course of chemical treatment. 18 cultivars has been classified as low resistant, 12 cultivars as moderate resistant and 4 cultivars as high resistant. None of the tested fungicides proved perfect biological efficacy (100% healthy berries). 4 of them proved high biological effect (more than 90% healthy berries), 3 proved low biological activity (less than 75% healthy berries) and 2 proved moderate biological activity (75–90% healthy berries).

Emerging Blumeria graminis f. sp. hordei pathotypes reveal ‘Psaknon’ resistance in European barley varieties

2015 ◽  
Vol 154 (6) ◽  
pp. 1082-1089 ◽  
Author(s):  
A. DREISEITL
Keyword(s):  
Powdery Mildew ◽  
Central Europe ◽  
Powdery Mildew Resistance ◽  
Quantitative Resistance ◽  
Spring Barley ◽  
Blumeria Graminis ◽  
Winter Barley ◽  
Cereal Crops ◽  
Alternative Source ◽  
The Czech Republic

SUMMARYBarley (Hordeum vulgare L.) is one of the most important cereal crops in the world and powdery mildew caused by the airborne fungus Blumeria graminis f. sp. hordei is a worldwide disease that causes frequent epidemics in Central and Northwestern Europe. Psaknon was one of first varieties in which powdery mildew resistance (Mlp1) was found, but no commercial variety with this resistance and no pathotype with the corresponding virulence have been recorded. In 2014, four isolates collected in the Czech Republic and virulent to Mlp1 were tested on 25 varieties and were also virulent to seven other resistances, including Venezia. These isolates revealed the presence of Mlp1 in six commercial spring and winter barley varieties from Southeastern and Central Europe and in six German winter barley candidate lines for registration in Czech variety trials. Based on the combined results of virulence and resistance, it was concluded that Vp1 is becoming a major factor contributing to increased virulence complexity and pathotype diversity in Central Europe. In breeding, employment of the non-specific resistance Mlo for spring barley and accumulation of quantitative resistance genes for winter barley can still be recommended in addition to exploiting a non-host resistance from an alternative source such as that present in Hordeum bulbosum.

scholarly journals Long-lasting changes in the species spectrum of cucurbit powdery mildew in the Czech Republic – influence of air temperature changes or random effect?

2010 ◽  
Vol 45 (Special Issue) ◽  
pp. S41-S47 ◽  
Author(s):  
A. Lebeda ◽  
B. Sedláková ◽  
E. Křístková ◽  
M. Vysoudil
Keyword(s):  
Czech Republic ◽  
Powdery Mildew ◽  
Air Temperature ◽  
Mixed Infection ◽  
Random Effect ◽  
Morphological Characteristics ◽  
Infection Prevalence ◽  
The Czech Republic ◽  
Field Crops ◽  
Influence Spreading

Two ectoparasite powdery mildew species <i>Golovinomyces cichoracearum</i> (<i>Gc</i>) and <i>Podosphaera xanthii</i> (<i>Px</i>) occurring on cucurbits differ, besides other characteristics, by specific ecologic requirements. While <i>Px</i> is common in subtropical and tropical areas and greenhouse crops, <i>Gc</i> occurs more frequently in temperate and cooler areas under field conditions. Their presence on cucurbit field crops (<i>Cucurbita pepo</i>, <i>C. maxima</i>, <i>Cucumis sativus</i>) was monitored in the Czechoslovakia (1979–1980) and in the Czech Republic (1995–2007). Their identification was carried out by microscopic observation of the morphological characteristics of the dry conidia on 1527 leaf samples. Data on air temperature in 1979–2007 were provided by the Czech Hydrometeorological Institute. In 1979–1980 <i>Gc</i> was identified in 86.0% of samples, <i>Px</i> in 14.0% samples, there was no mixed infection; prevalence of <i>Px</i> was recorded in South Slovakia and South Moravia, and on crops under cover. Since 1995 species <i>Px</i> was recorded each year on field crops in different locations of Bohemia and Moravia, usually in mixed infection with <i>Gc</i>. The average year temperature of 8.1°C for period 1992–2007 was higher than corresponding value of 7.4°C in 1979–1983. Similarly, average temperature in vegetation season of 16.2°C in 1992–2007 was higher than corresponding value of 15.7°C in 1979–1983. The higher air temperature can positively influence spreading of <i>Px</i> in the Czech Republic. Climate variability and effect of their changes are discussed in relationship to the geographic distribution and geographic patterns of cucurbit powdery mildews.

scholarly journals  Faecal shedding of verotoxigenic Escherichia coli in cattle in the Czech Republic

2011 ◽  
Vol 56 (No. 4) ◽  
pp. 149-155 ◽  
Author(s):  
P. Alexa ◽  
L. Konstantinova ◽  
Z. Sramkova-Zajacova
Keyword(s):  
Escherichia Coli ◽  
Czech Republic ◽  
Dairy Cattle ◽  
Age Groups ◽  
Immunomagnetic Separation ◽  
The Other ◽  
Somatic Antigen ◽  
The Czech Republic ◽  
E Coli ◽  
One Year

A survey to estimate the prevalence of verotoxigenic E. coli (VTEC) or enterohaemorrhagic E. coli (EHEC) in rectal swabs from healthy dairy cattle aged three weeks, three months and one year was conducted in three herds from the Czech Republic. Screening for the presence of the stx1, stx2 and eaeA genes in faecal swab cultures was performed by PCR, and in positive samples, isolated colonies were examined. Immunomagnetic separation was used for the isolation of the VTEC serogroup O157 from samples. VTEC were detected in animals from all three herds under study. In the group of 3-week-old calves, VTEC were only detected in samples collected in the summer months. However, in the other age-groups, VTEC were detected in both the summer and winter months. EHEC shedding was observed in 30 to 100% of the total samples collected from cattle aged three months and one year in the summer months, and in 30 to 60% of samples taken in the winter months. EHEC strains of serogroup O157 were detected in two herds. The range of verotoxins shed by VTEC isolates of serogroup O157 differed between herds. Besides serogroup O157, additional EHEC belonging to the antigen groups O26, O103, O128 and O153 have been identified, and in some of them, no somatic antigen was detected.

First record of powdery mildew on Homalocladium platycladum in the Czech Republic

2007 ◽  
Vol 56 (4) ◽  
pp. 722-722 ◽  
Author(s):  
A. Lebeda ◽  
B. Mieslerová ◽  
V. Rybka ◽  
M. Sedlářová ◽  
I. Petrželová
Keyword(s):  
Czech Republic ◽  
Powdery Mildew ◽  
First Record ◽  
The Czech Republic

scholarly journals Severity of powdery mildew on winter barley in the Czech Republic in 1976–2005

2008 ◽  
Vol 43 (No. 3) ◽  
pp. 77-85 ◽  
Author(s):  
A. Dreiseitl
Keyword(s):  
Czech Republic ◽  
Powdery Mildew ◽  
Disease Severity ◽  
Field Trials ◽  
Winter Barley ◽  
Sources Of Resistance ◽  
The Czech Republic ◽  
High Infection ◽  
High Disease Severity ◽  
Important Disease

Results of scoring the reaction to powdery mildew of 240 winter barley varieties that were gradually included in 392 Czech Official Trials conducted at 21 locations were analysed. The reaction of the varieties was determined on the basis of the level of infection by the disease. Therefore, the data can also be used to assess the disease severity in years and at locations. Several characteristics indicative of disease severity were considered, including the disease severity coefficient (= average infection of susceptible varieties in trials with a high disease severity/the proportion of such trials). The value of the coefficient is inversely proportional to disease severity. The highest powdery mildew severity was found in 1976, and the years 1988, 1990 and 2003 were characterised by high infection of the examined varieties. In contrast, the disease was practically absent in 1979 and 1982, and its severity was also low in 1978, 1981, 1985, 1991 and 1998. Very low disease severity was found for the period 1977–1982 when insufficient disease severity was found on average in 78% of the trials and high disease severity in only 6% of the trials. The highest disease severity was found at locations Trutnov, Horažďovice and Chrastava. The analysis of data from a large number of field trials conducted at various locations for a period of 30 years confirmed that powdery mildew is an important disease of winter barley in the Czech Republic. Known genetic sources of resistance and current methods, such as marker assisted selection, enable breeders to solve this problem.

scholarly journals Fabian two-row winter barley

2013 ◽  
Vol 49 (No. 4) ◽  
pp. 175-177
Author(s):  
Z. Nesvadba ◽  
J. Špunar ◽  
M. Kadlíková
Keyword(s):  
Czech Republic ◽  
Powdery Mildew ◽  
Plant Height ◽  
Cold Hardiness ◽  
Medium Density ◽  
The Czech Republic ◽  
Variety Trials ◽  
Growing Conditions ◽  
Moderate Resistance ◽  
Very High

Fabian is a medium-late two-row feedin barley of winter habit developed at Agrotest Fyto, Ltd., Kroměř&iacute;ž, Czech Republic (breeders&rsquo; rights holder) and registered in the Czech Republic in 2011. In the Official Variety Trials it showed high grain yields under intensive growing conditions (104.5%) and medium yields under low input conditions (101.1%). Fabian has the highest cold hardiness of the registered two-row winter barleys and regenerates very well in the spring. Its resistance to powdery mildew is very high (score 8.2 on a 1&ndash;9 scale). It has medium plant height, moderate resistance to lodging and large yellow kernel. The spike is long and of medium density.

scholarly journals Virulence frequencies to powdery mildew resistance genes of winter barley cultivars

2010 ◽  
Vol 40 (No. 4) ◽  
pp. 135-140 ◽  
Author(s):  
A. Dreiseitl
Keyword(s):  
Czech Republic ◽  
Powdery Mildew ◽  
Resistance Genes ◽  
Powdery Mildew Resistance ◽  
Spring Barley ◽  
Winter Barley ◽  
The Czech Republic ◽  
Mildew Resistance ◽  
Barley Cultivars ◽  
Random Samples

The virulence frequencies to powdery mildew resistance genes possessed by winter barley cultivars registered and newly tested in the Czech Republic were studied in 2000, 2002 and 2004. Random samples of the populations originating from winter and spring barley fields were obtained from the air by a mobile version of a jet spore sampler mounted on a car roof. Conidia were sampled by driving across the Czech Republic. Fourteen differentials, carrying 18 out of 20 currently identified resistance genes present in winter barley cultivars, were used. High virulence frequencies (85&ndash;100%) to most resistance genes were found. Lower virulence frequencies (14.1&ndash;40.1%) were found to only three resistance genes that have not been described yet; their preliminary designations are Ml(Va), Ml(Dt) and Ml(Ca). The importance of resistance of winter barley cultivars is discussed with respect to limiting the speed with which the pathogen adapts to genetic resistances possessed by commercial cultivars of both winter and spring barley, and to the necessity of lowering the costs for powdery mildew control in barley.

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