Identification of Resistance Sources to Yellow Rust in Some Genotypes of Bread Wheat Collection of the National Plant Gene Bank of Iran

To identify resistance sources to wheat yellow rust (Puccinia striiformis. f. sp. tritici) in bread wheat collection of the National Plant Gene Bank of Iran, 41 genotypes of bread wheat were evaluated against four races of yellow rust. The isolates collected from Gorgan, Karaj, Mashhad and Sari, propagated as single pustules and inoculated on differential sets to determine the races. Genotypes were evaluated in three replications in a green house at seedling stage, separately for each race. By investigating on the reaction of the differential sets to the isolates, four isolates of Gorgan, Karaj, Mashhad and Sari were designated as 6E6A+, 134E134A+, 134E142A+ and 6E4A+, respectively. All four races were virulent on Yr2, Yr6, Yr7, Yr9, Yr25, Yr24 and YrA. None of the races were virulent on Yr1, Yr3, Yr4, Yr5, Yr8, Yr10, YrSD, YrCV and YrSP. Twenty-nine genotypes (46.7%) were resistant to all four races. These genotypes were from different origin (East-Azarbayjan, Khorasan, Kordestan, Kermanshah, Lorestan, Markazi, Hamedan, Portugal, China). Comparison of reaction genotypes against the studied races in comparison with differential varieties indicated that some genotypes may have a different resistance gene than the differential varieties do or they may contain a combination of two or more resistance genes. In conclusion, the results of this research indicated the potential of genetic resources for resistance to yellow rust in bread wheat collection of the National Plant Gene Bank of Iran.