Wheat rusts, caused by the fungal pathogen Puccinia sp. are serious economic diseases of wheat worldwide. Surveillance, monitoring and new virulence identification are prerequisites for future race prediction and for effective breeding programs. Therefore, we decided to compile the endeavours done for surveillance over eight cropping seasons in Lebanon. The extensive field surveys were conducted yearly in major bread and durum wheat areas over the period 2009-2017 using the Borlaug Global Rust Initiative surveillance protocols. Over eight years, 136 locations were surveyed, 56 samples were collected from mainly stripe and stem rust, and X samples were phenotyped using a robust set of standards differentials lines used worlwide at Tel Hadya - ICARDA, 6 phenotyped at INRA - Grignon, 4 phenotyped at the Global Rust Reference Center (GRRC), until the season 2015-2016 the cereal rust laboratory at LARI became autonomous in race analysis. Six samples were genotyped. The latest phenotyping showed that pathotypes had combinations of the virulence for the widely deployed genes Yr2, Yr6, Yr7, Yr8, Yr9, Yr25 and Yr27 resembling to the aggressive strain PstS2, the invasive high temperature tolerant isolate. Resistance genes Yr1, Yr3, Yr4, Yr5, Yr10, Yr15, Yr17, Yr32, and YrSP were effective against all isolates. Race typing of the stem rust sample using the North American stem rust differential sets indicated presence of TKTTF in surveyed wheat growing areas as well as at ICARDA's research station in Terbol. Identified races have been used in field artificial inoculation of ICARDA's breeding program during the last two years. In conclusion, the races PstS2 and TKTTF were the dominant prevalent races in the country for yellow and stem rust respectively. This information could be useful for the region for better integrated disease management and wider diversification of resistance genes deployment in breeding programs.
Summary on the pathogenic variability of wheat rusts in Lebanon over the period 2009-2017
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