Resistance of ‘Laverda’ to powdery mildew and its presence in some winter barley cultivars

2011 ◽  
Vol 39 (4) ◽  
pp. 569-576 ◽  
Author(s):  
A. Dreiseitl
2010 ◽  
Vol 40 (No. 4) ◽  
pp. 135-140 ◽  
Author(s):  
A. Dreiseitl

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.


2011 ◽  
Vol 41 (No. 2) ◽  
pp. 45-50 ◽  
Author(s):  
A. Dreiseitl

Powdery mildew resistances in Czech winter barley breeding lines were postulated on the basis of their reaction types to 32 pathotypes of the pathogen with different combinations of virulence genes. The results from testing 38 lines represent a substantial part of found variability in the examined trait with 13 found resistances. The resistances typical of winter barley cultivars dominated in six-row lines whereas the resistances typical of spring barley cultivars were more frequent in two-row lines. None of these resistances was effective enough to all used pathotypes. Desired effectiveness is present neither in the lines with a combination of corresponding resistances nor in the cases when their resistance is controlled by more (up to six) postulated genes. Resistances “Ch” (detected in the line CH 669) and “Lu” (detected in the line LU 1258/A/02) are novel, the former without any practical importance. A need of breeding winter barley cultivars resistant to powdery mildew is discussed since they are required for both conventional and particularly low-input farming systems.


Author(s):  
Antonín Dreiseitl

In 2006–2010, resistance to the powdery mildew pathogen was studied in 225 winter barley cultivars of which 86 two-rowed and 139 six-rowed. The examined set included 59 cultivars tested in the official variety trials and 166 cultivars in variety trials conducted by domestic breeding stations in that period. Thirteen known resistances were identified (Ar, Bw, Dr2, Ha, HH, IM9, La, Ly, Ra, Ru, Sp, St and We). No resistance was found in one cultivar only. The most frequent resistance was Ra detected in 114 cultivars (= 50.7%). The resistance Bw was found in 54 cultivars (24.0%). Resistances typical for spring barley cultivars (Ly, Sp, Ru and We) were also frequent (4.0% to 23.6%). Unknown resistances were found in 20 cultivars, in nine of which they were effective to all used pathotypes of the pathogen. Thirty-six cultivars (16.0%) exhibited heterogeneity in the examined trait, i.e. they were mostly composed of lines with different resistances. Research on cultivars possessing unknown resistances continues.


2011 ◽  
Vol 47 (No. 2) ◽  
pp. 64-68 ◽  
Author(s):  
A. Dreiseitl

In the last two decades, resistance to the powdery mildew pathogen has been investigated in a large number of barleys in the Czech Republic. Several tens of winter barley cultivars were identified with a resistance based on an unknown gene or unknown combinations of resistance genes. In this paper tests on 20 of these cultivars are presented. Thirty-two reference isolates of Blumeria graminis f.sp. hordei were used. All the 20 cultivars shared a particular, previously unknown resistance. Landi was the first cultivar registered with this resistance and it is recommended that this resistance be designated Ln. Isolates virulent to Ln were already found randomly in old European, and also in non-European pathogen populations, where cultivars possessing the resistance Ln were never grown. On the other hand, the resistance Ln has been highly effective even 13 years after Landi registration.


2009 ◽  
Vol 44 (No. 4) ◽  
pp. 160-166 ◽  
Author(s):  
A. Dreiseitl

Virulence frequencies to powdery mildew resistances in winter barley cultivars mostly registered in the Czech Republic were studied in 2007 and 2008. Random samples of the air populations originating from winter and spring barley fields were obtained by means of a mobile version of a jet spore sampler. Conidia were sampled by driving across the Czech Republic. In total 349 isolates were studied and 17 differentials were used. The virulence frequencies to specific resistances of given cultivars showed wide range from 0% to 100%. Nine differentials were used to distinguish 134 pathotypes, of which 32 representing 63.9% of isolates were detected in both years. Pathotype 773, which broke down the resistance of eight differentials, was the most abundant. In 2008, lower virulence frequencies to all differentials, and thus lower population complexity, were determined, which may be caused by different regional origins of the isolates examined. Importance of the study of the given pathogen population is discussed in terms of successful breeding of resistant barley cultivars.


2008 ◽  
Vol 43 (No. 3) ◽  
pp. 87-96 ◽  
Author(s):  
A. Dreiseitl

The results of evaluation of powdery mildew resistance in winter barley varieties in 285 Czech Official Trials conducted at 20 locations were analysed. Over the period, the number of varieties tested per year increased from four to seven in 1976−1985 to 53−61 in 2002−2005. To assess the resistance of varieties, only trials with sufficient disease severity were used. In 1976−2000, six varieties (1.7% of the varieties tested in the given years) ranked among resistant (average resistance of a variety in a year > 7.5) including NR-468 possessing the gene <i>Mla13</i>, KM-2099 with <i>mlo</i> and Marinka with the genes <i>Mla7</i>, <i>MlaMu2</i>. In 2001−2005, already 33 varieties (16.9%) ranked among resistant, of which Traminer possessing the genes <i>Ml(St)</i> and <i>Ml(IM9 </i> dominated. The proportion of susceptible varieties (average resistance ≤ 5.5) did not change in the two mentioned periods. Two-rowed varieties began to be tested as late as in 1990 (the first variety was Danilo), however, no difference was found in the resistance of two- and six-rowed varieties. Using an example of two pairs of varieties (Dura-Miraj and Marinka-Tiffany) with identical genes for specific resistance but with different resistance in the field, the efficiency of non-specific resistance is discussed. The resistance of domestic and foreign varieties was similar in 1994−2000; however, in 2001−2005 the difference was 0.75 point to disadvantage of domestic ones.


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