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Kroměříž, Czech Republic

Dreiseitl A.,Agricultural Research Institute Kromeriz Ltd.
Annals of Applied Biology | Year: 2011

Information on disease severity assists greatly with making decisions about crop protection systems. However, there are no published long-term field trials in different locations to determine the severity of individual diseases. National trials that relate to the agronomic traits of varieties, including disease responses, are available. The current article describes the use of such data to determine disease severity based on official Czech variety trials. In total, 838 and 334 field trials of spring and winter barley, respectively, conducted from 1976 to 2005, were analysed. To compare year to year powdery mildew severity, five parameters were used. Annual disease severity in both crops differed substantially, whereas similarity of the disease severity was rare. During the last 15 years, disease severity in spring barley was stable despite a rapid increase in the area of fully resistant spring barley varieties, particularly those with the gene mlo. During the period 1976-2005, the mean disease severity in winter barley accounted for 64.1% of the mean disease severity in spring barley. The effect of deployment of the resistance genes and growing areas of winter barley on the determined disease severity was analysed. The method described here allows easy comparisons to be made of disease severity among years, locations and different crops and diseases if similar scoring scales for disease infection evaluation are used. © 2011 The Author. Annals of Applied Biology © 2011 Association of Applied Biologists. Source

Dreiseitl A.,Agricultural Research Institute Kromeriz Ltd. | Krianova K.,HORDEUM Ltd. Novy
Cereal Research Communications | Year: 2012

Spring barley was the second largest crop in Slovakia. Resistance genes in cultivars registered in Slovakia from 2000 to 2010 were identified using the postulation method. Forty-three cultivars including 30 individually harvested plants, two parents 'Meltan' and 'Pax' and a standard line SK5968 were tested at the seedling stage for their reaction to 40 selected isolates of Blumeria graminis f. sp. hordei. In total, 19 resistance spectra were detected and the following 13 resistance genes were postulated, namely mlo, Mla1, Mla6, Mla12, Mla13, MlaRu4, Mlat, Mlg, MlLa, Ml(Ab), Ml(Hu4), Ml(Ro) and Ml(St). Two unknown resistances were detected in 'Calcule' and 'Spilka'. Two cultivars ('Madonna' and 'Nadir') exhibited heterogeneity for mildew resistance. The most frequent gene was mlo, which was present in 25 of the tested cultivars. Some new results to previously published data were found. Source

Dreiseitl A.,Agricultural Research Institute Kromeriz Ltd. | Dreiseitl A.,Hermitage Research Facility | Platz G.,Hermitage Research Facility
Crop and Pasture Science | Year: 2012

Barley (Hordeum vulgare L.) is a major crop in Australia and powdery mildew (Blumeria graminis f. sp. hordei) is one of its most common diseases. Genes for resistance to powdery mildew were postulated for 86 Australian barley varieties and nine advanced breeding lines using 40 reference isolates of the pathogen. Fifty isolates collected in Australia in 2011 were used for additional tests of some varieties. In total, 22 known resistance genes [mlo, Mla1, MlaAl2, Mla3, Mla6, Mla7, Mla8, Mla9, Mla12, Mla13, Mlat, Mlg, MlGa, Mlk1, MlLa, Mlra, Ml(Ab), Ml(Ch), Ml(Dr2), Ml(He2), Ml(Lo) and Ml(St)] were detected. The most frequent genes were Mla8 and Mlg present in 43 and 34 varieties, respectively, while MlGa was found in 12 varieties. Each of the specific resistance genes Mla1, Mla3, Mla6, Mla9, Mla13, Ml(St) and the non-specific recessive gene mlo was found in one variety only. The varieties Maritime and Stirling appear to carry no specific resistance genes. Fifteen unknown resistances were detected. It is recommended that Australian barley breeding programs exploit European varieties possessing mlo to improve the resistance to powdery mildew in new varieties. © CSIRO 2012. Source

Repkova J.,Masaryk University | Dreiseitl A.,Agricultural Research Institute Kromeriz Ltd.
Euphytica | Year: 2010

PI284752, an accession of wild barley (Hordeumvulgare ssp. spontaneum) resistant to powdery mildew caused by Blumeriagraminis f.sp. hordei, was studied with the aim of identifying genes involved in powdery mildew resistance. An F2 population (456 plants) was established from a cross between the winter barley variety 'Tiffany' and PI284752. This cross demonstrated a two-locus model of resistance. Linkage analysis using polymorphic DNA markers was carried out on 180 plants. The RGH1a gene sequence from the Mla locus was used as a source for developing the RGH1aE2I2 marker. By interval mapping on chromosome 1HS, one resistance gene was found to be tightly linked with RGH1aE2I2 and it was found to be located 2 cM from GBMS062. In F2 plants exhibiting resistance reaction type (RT) 0, specific DNA fragments for the RGH1aE2I2 marker were amplified. In plants with RT1 to RT2-3, the resistance was conferred exclusively by the second R gene that we identified, which is linked with Bmac0134 and GBMS247 on chromosome 2HS. The aforementioned markers may be valuable candidates for marker-assisted selection of resistant genotypes conferred by one or both genes. © 2009 Springer Science+Business Media B.V. Source

Powdery mildew caused by the airborne biotrophic fungus Blumeria graminis f. sp. hordei is a common disease of barley. Although it can be controlled by fungicide applications, genetic resistance is an efficient and more environmentally acceptable way of limiting its effect on yield and quality. Spring barley is the second largest cereal crop in the Czech Republic and seventy spring barley cultivars (cvs.) were registered from 1996 to 2010. Seedlings of 43 cvs. were tested for reaction to selected isolates of the pathogen and resistance genes were identified using the postulation method. The following 12 known resistance genes were postulated namely, mlo, Mla6, Mla8, Mla12, Mla13, MlaRu4, MlaN81, Mlg, MlLa, Ml(Ab), Ml(Ro) and Ml(St) and two unknown resistances were found in Paulis and Prosa. Four cvs. (Azit, Paulis, Respekt and Tocada) were heterogeneous for mildew response. The most frequently found gene was mlo, which was present in 29 cvs. In nine of 15 cvs. without mlo, Mlg occurred and in seven cvs. genes located in the Mla locus were postulated. A newly identified resistance in Prosa will be further characterised. This report demonstrates that resistance gene postulation from multi-race tests remains an essential research tool for postulating genes for resistance to plant pathogens. © 2012 Springer Science+Business Media B.V. Source

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