Genetic variation of virulence in Iranian isolates of Mycosphaerella graminicola using wheat differential cultivars

For resistance to septoria tritici blotch, information on genetic variation of Pathogenicity and virulence in population of the causal agent is necessary to improve resistant cultivars based on the effective genes in a region. To determine the genetic variability of Mycosphaerella graminicola, the cause of septoria tritici blotch disease, seedling reaction of 21 differential cultivars, containing one or few resistant genes (Stb) each, together with four susceptible check cultivars was evaluated against 13 isolates of the pathogen collected from Goleta, Khuzestan and Liam provinces of Iran during 2011-2013. The experiment was carried out in a completely randomized design in greenhouse of Cereal Research Department, Seed and Plant Improvement Institute in Karaj. The reaction of seedlings was assessed based on percentage of necrotic areas and pycnidial coverage of leaves and Avirulence / Virulence formula for each isolate was determined.Based on the results, thirteen different Pathotypes were determined. Differential cultivars Arina, Riband and M3 containing Stb15, 6, Stb15 and Stb16, 17, respectively were resistant to all isolates. According to the frequency of virulence genes of M. graminicola isolates, virulence factors were not exist for resistance genes Stb15, Stb16 and Stb17.