In order to investigate pathogenic variation in population of the causal agent of yellow rust, and evaluate resistance of wheat cultivars and advanced lines released before and after 1992, the year of epidemic of yellow rust in Iran, known genotypes for resistance to yellow rust, including yellow rust differential cultivars, yellow rust near isogenic lines, some sources for adult-plant resistance genes, and genotypes carrying factors for durable resistance, were evaluated in Northern, Northeast and West provinces of Iran. According to the results obtained, virulence factors for Yr1 were present in Neishabour, Torogh, and Jolgehh Rokh in Khorasan province (Northeast) for Yr2 in Neishabour, Torogh, and Jolgeh Rokh (Northeast), Kalaleh and Gharakhill (North) Ultan, Jafarabad, and Alagrogh (Northwest) for Yr3 in Neishabour for/Yr6, Yr7, and Yr9 in all regions for Yr8 in Jolgeh Rokh, Kalaleh, Ultan, Jafarabad, and Alarogh for Yrll in Torogh and Gorgan for Yr12 in Torogh, Gorgan, and Ultan for Yr18 in all regions except Agh Ghala and Torogh for Yr22, Yr23, Yr25, and YrA in all regions for YrSu in Lalaleh, lafarabad, and Alarogh for undesignated resistance genes present in Nugains cultivar (YrA1 and YrA2) in Neishabour, Torogh, Jolgeh Rokh, Gorgan, Jafarabad, and Alarogh for Yr27 (YrSK) in Torogh. For genes Yr4, Yr5, Yr10, Yr14, Yr15, Yr24, YrSD, YrCV, and YrSP virulence factors were not observed so far, thus these genes are recommended as effective genes, which can be used as resistance sources for use in breeding programs. All Iranian old wheat varieties, which had been released before 1992, were highly susceptible in all nurseries and among newly released varieties, Tajan was susceptible in Torogh Mahdavi in Neishabour Alamout and Zarrin in Torogh Alvand in Neishabour Chamran in Neishabour and Jolgeh Rokh. Wheat advanced lines C-73-5 and 8-75-20 were susceptible in Alarogh, M-75-10 in Jolgeh Rokh, M-75-19 in Kalaleh, and N-75-5 in Torogh. |