Quantitative Differences in Powdery Mildew Resistance Among Spring Barley Cultivars

1986 ◽  
Vol 115 (3) ◽  
pp. 222-228 ◽  
Author(s):  
M. Heun
Keyword(s):  
Powdery Mildew ◽  
Powdery Mildew Resistance ◽  
Spring Barley ◽  
Mildew Resistance ◽  
Barley Cultivars

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 (85–100%) to most resistance genes were found. Lower virulence frequencies (14.1–40.1%) 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.

Powdery Mildew Resistance Genes in 127 Northwest European Spring Barley Varieties

1992 ◽  
Vol 108 (3) ◽  
pp. 210-228 ◽  
Author(s):  
H. P. Jensen ◽  
E. Christensen ◽  
J. Helms Jorgensen
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Powdery Mildew Resistance ◽  
Spring Barley ◽  
Mildew Resistance

scholarly journals Powdery Mildew Resistance of Foreign Spring Barley Varieties in Czech Official Trials

2011 ◽  
Vol 42 (No. 1) ◽  
pp. 1-8 ◽  
Author(s):  
A. Dreiseitl
Keyword(s):  
Powdery Mildew ◽  
Powdery Mildew Resistance ◽  
Spring Barley ◽  
Mildew Resistance ◽  
Homogeneous Varieties

In 1993–2005, resistance to powdery mildew was studied in 168 foreign varieties of spring barley included in Czech Official Trials in that period. Sixteen known resistances to powdery mildew were identified (Ab, Al, Ar, HH, Kw, La, Ly, MC, Mlo, N81, Ri, Ru, Sp, St, Tu, and We). Unknown resistances were found in 32 varieties, in nine of which these resistances were effective against all used pathotypes of the pathogen. Seven varieties (= 5%) exhibited heterogeneity in the examined trait, i.e. they are composed of lines (usually of two) with different resistances to powder mildew. The resistance Mlo, which was found in 75 homogeneous varieties (= 46%), dominated in the set. The resistances Ru, We, Ar and La were frequently present. The examined set includes 53% of varieties resistant to all used indigenous pathotypes of the pathogen.  

scholarly journals Powdery Mildew Resistance of Czech and Slovak Spring Barley Breeding Lines in Variety Trials

2011 ◽  
Vol 41 (No. 4) ◽  
pp. 160-166 ◽  
Author(s):  
A. Dreiseitl
Keyword(s):  
Powdery Mildew ◽  
Considerable Increase ◽  
Powdery Mildew Resistance ◽  
Spring Barley ◽  
Mildew Resistance ◽  
Breeding Lines ◽  
Breeding Station ◽  
Low Diversity ◽  
Mla Locus ◽  
The Given

In 2001–2005, resistance to powdery mildew was studied in 227 Czech and Slovak breeding lines of spring barley included in the breeding station trials or official trials. Seventeen known resistances were identified (Al, Ar, At, HH, Kr, La, Ly, Mlo, N81, Ri, Ru, Sp, St, Tu, We, Mla21, and Mlp1). Unknown resistances were found in 11 breeding lines, in five of which resistance was effective against all used pathotypes of the pathogen. Besides the identified resistances, unknown resistances were detected in another three breeding lines. Sixty-five breeding lines (= 29%) exhibited heterogeneity in the examined trait, i.e. they are composed of components with different resistances to powdery mildew. Comparison of current results with the previous ones shows a considerable increase in the proportion of breeding lines carrying the resistance Mlo (72%), on the account of the resistances located at the Mla locus, particularly Ru. The examined set is characterised by a high proportion of breeding lines resistant to all used Czech pathotypes of the given pathogen (78%), however of low diversity in the resistance.  

scholarly journals MILDEW LOCUS O Mutation Does Not Affect Resistance to Grain Infections with Fusarium spp. and Ramularia collo-cygni

2015 ◽  
Vol 105 (9) ◽  
pp. 1214-1219 ◽  
Author(s):  
Katharina Hofer ◽  
Andrea Linkmeyer ◽  
Katharina Textor ◽  
Ralph Hückelhoven ◽  
Michael Hess
Keyword(s):  
Cell Death ◽  
Powdery Mildew ◽  
Fungal Pathogens ◽  
Powdery Mildew Resistance ◽  
Natural Infection ◽  
Spring Barley ◽  
Susceptibility Gene ◽  
Fusarium Spp ◽  
Mildew Resistance ◽  
Barley Powdery Mildew

MILDEW LOCUS O defines a major susceptibility gene for powdery mildew, and recessive mlo resistance alleles are widely used in breeding for powdery mildew resistance in spring barley. Barley powdery mildew resistance, which is conferred by mlo genes, is considered to be costly in terms of spontaneous defense reactions and enhanced susceptibility to cell-death-inducing pathogens. We assessed fungal infestation of barley (Hordeum vulgare) grain by measuring fungal DNA after natural infection with Fusarium spp. and Ramularia collo-cygni or after inoculation with Fusarium spp. in the field. Powdery-mildew-resistant mlo5 genotypes did not show enhanced Fusarium spp. or R. collo-cygni DNA content of grain over four consecutive years. Data add to our understanding of pleiotropic effects of mlo-mediated powdery mildew resistance and contributes to the discussion of whether or not application of barley mlo mutations may support pathogenesis of cell-death-inducing fungal pathogens under field conditions.

Haplotype characterization and markers at the barley Mlo powdery mildew resistance locus as tools for marker-assisted selection

Genome ◽  
2006 ◽  
Vol 49 (8) ◽  
pp. 864-872 ◽  
Author(s):  
G Tacconi ◽  
V Baldassarre ◽  
N C Collins ◽  
D Bulgarelli ◽  
A M Stanca ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Marker Assisted Selection ◽  
Powdery Mildew Resistance ◽  
Resistance Locus ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Mildew Resistance ◽  
Barley Cultivars ◽  
Barley Powdery Mildew ◽  
Almost All

Recessive mlo alleles of the barley Mlo gene confer resistance to almost all known isolates of the powdery mildew fungal pathogen targeting barley (Hordeum vulgare). To characterize haplotypes present in the Mlo chromosomal region of cultivated Mlo and mlo barley genotypes, weconducted a polymorphism search in 3 predicted low-copy sequence regions adjacent to the Mlo gene by examining a sample of 4 Mlo and 3 mlo cultivars. Eight single-nucleotide polymorphisms (SNPs) and 1 insertion–deletion (indel) were detected, and easy to use PCR-based markers were developed for typing the SNPs. The PCR markers were used to characterize a collection of 46 Mlo and 25 mlo barley cultivars, identifying 3 distinct mlo-11 haplotypes, 1 mlo-9 haplotype, and 4 Mlo haplotypes. We summarized the haplotype and marker information obtained here and in a previous study to help breeders identify strategies for mlo marker-assisted selection. The ability of the markers to identify mlo-resistant genotypes in segregating populations was demonstrated using 2 resistance-characterized F2 populations derived by 3-way crosses.Key words: barley, powdery mildew resistance, mlo, SNPs, marker-assisted selection.

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