University of Guilan Cereal Research 2252-0163 10 4 2021 02 19 Identification of the virulence factors of Blumeria graminis f.sp hordei, the causal agent of barley powdery mildew in northeast and northern regions of Iran Identification of the virulence factors of Blumeria graminis f.sp hordei, the causal agent of barley powdery mildew in northeast and northern regions of Iran 339 349 4830 10.22124/cr.2021.18839.1648 FA Reza Aghnoum Research Assoc. Prof., Dept. of Seed and Plant Improvement Research, Khorasan Razavi Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Mashhad, Iran Mohammad Ali Dehghan Researcher, Dept. of Seed and Plant Improvement Research, Golestan Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Gorgan, Iran Shapoor Ebrahimnejad Researcher, Dept. of Seed and Plant Improvement Research, Mazandaran Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Sari, Iran Rahim Mehrabi Research Assoc. Prof., Dept. of Cereal Research, Seed and Plant Improvement Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran (The present address: Assoc. Prof., Dept. of Agricultural Biotechnology, Journal Article 2020 10 28 Powdery mildew of barley caused by the fungal pathogen, Blumeria graminis f.sp. hordei, is one of the most important leaf diseases of barley in Iran. This study was carried out to determine the virulence factors in the population of the fungus causing powdery mildew in major conductive regions of the disease in the northeast and north regions of Iran and to identify new sources of resistance. Trap nurseries (53 lines and cultivars) including cv. Pallas, 18 near-isogenic lines in the background of Pallas and a supplementary set including 34 cultivars carrying known or unknown resistance gene (s) were evaluated against powdery mildew under the natural conditions at four powdery mildew hotspot locations in northeast and north of Iran including Mashhad, Karaj, Gorgan and Ghaemshar, during three consecutive cropping seasons (2014-2016). The results of evaluation of near-isogenic lines and supplementary set in different regions showed that there was a variation in virulence spectrum of the pathogen in these locations. Virulence factors for Mlk(1), Mlp, Mlat, MlLa, Mlh, Mla22 and Mlk resistance genes appear to be common in all locations. These genes are reported as ineffective resistance genes in Iran. Virulence for the Mlp gene that was reported to be effective in many regions was appeared in Mashhad, Gorgan and Ghaemshar. The results of this study also indicated that the new virulence factors is appeared for the MlLa gene in Mashhad, Gorgan and Ghaemshar, for the Mlg and MlCP resistance genes in Mashhad and Gorgan and for the Mla3 resistance gene in Mashhad. The findings of this study indicate that the Mla7, Ml(No3), mlo5 Mla9, Mla13, ، Ml(Ru3), Mla10, Ml(Du2), Mla12, Ml(Em2) are effective in Iran and could be used as new sources of resistance in breeding programs. Powdery mildew of barley caused by the fungal pathogen, Blumeria graminis f.sp. hordei, is one of the most important leaf diseases of barley in Iran. This study was carried out to determine the virulence factors in the population of the fungus causing powdery mildew in major conductive regions of the disease in the northeast and north regions of Iran and to identify new sources of resistance. Trap nurseries (53 lines and cultivars) including cv. Pallas, 18 near-isogenic lines in the background of Pallas and a supplementary set including 34 cultivars carrying known or unknown resistance gene (s) were evaluated against powdery mildew under the natural conditions at four powdery mildew hotspot locations in northeast and north of Iran including Mashhad, Karaj, Gorgan and Ghaemshar, during three consecutive cropping seasons (2014-2016). The results of evaluation of near-isogenic lines and supplementary set in different regions showed that there was a variation in virulence spectrum of the pathogen in these locations. Virulence factors for Mlk(1), Mlp, Mlat, MlLa, Mlh, Mla22 and Mlk resistance genes appear to be common in all locations. These genes are reported as ineffective resistance genes in Iran. Virulence for the Mlp gene that was reported to be effective in many regions was appeared in Mashhad, Gorgan and Ghaemshar. The results of this study also indicated that the new virulence factors is appeared for the MlLa gene in Mashhad, Gorgan and Ghaemshar, for the Mlg and MlCP resistance genes in Mashhad and Gorgan and for the Mla3 resistance gene in Mashhad. The findings of this study indicate that the Mla7, Ml(No3), mlo5 Mla9, Mla13, ، Ml(Ru3), Mla10, Ml(Du2), Mla12, Ml(Em2) are effective in Iran and could be used as new sources of resistance in breeding programs.

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