Abstract :
The stripe (Yellow) rust in wheat is one of the most important plant diseases in Iran. Since 1993 several epidemics have occurred in Iran causing the breakdown of widely utilized sources of resistance in wheat cultivars. Twenty-seven pathotypes were identif ied during 2003 and 2004 in greenhouse tests. Pathotypes 6E6A+, 6E22A+, 6E130A+, 6E134A+, 6E142A+, 6E158A+, 134E130A+ and 134E142A+ were more common during the course of this study. Virulence on plant/s with gene/s Yr2, Yr6, Yr7, Yr8, Yr9, Yr24,Yr25, YrSD, YrSP, Yr3N, Yr2+, Yr6+, Yr9+, Yr7+, Yr32+ and YrA was detected under greenhouse conditions. The majority of isolates with a high f requency (more than 88%) showed virulence on plant/s with Yr2, Yr6, Yr7, Yr9, YrA and Yr24 genes. No virulence was detected on plant/s with Yr1, Yr3V, Yr4, Yr5, Yr10 and YrSU genes. In a greenhouse test, f requency of virulence to wheat genotypes with the Yr32+, YrSP and YrSD gene was less than 7%; f requency of virulence to all other wheat genotypes was between 19 and 100%. During three years of f ield study, virulence on wheat genotypes Heines Kolben (with genes Yr2 and Yr6), Kalyansona (Yr2), Lee (Yr7), Avocet R (YrA), Federation*4/Kavkaz (Yr9) and TP1295 (Yr25) was common. No virulence was observed on plants with Yr1, Yr3V, Yr3N, Yr4, Yr5, Yr8, Yr10, Yr18, Yr24, Yr32+, YrSP, YrSD and YrSU genes in the trap nurseries. The coefficient of inf ection (C. I.) of the adult plant resistance gene, Yr18, was between 16-64 with moderate susceptibility and is going to be used in the breeding program in combination with other resistant sources
