8th INTERNATIONAL WHEAT CONFERENCE

geNeTIC dIVeRSITy of The fuNgAL WheAT PAThogeN
myCoSPhAeReLLA gRAmINICoLA IN IRAN
Somayyeh Fallahi-Motlagh 1 , Ramin Roohparvar 2
and Mohammdreza Zamanizadeh 1
1 Department of Plant pathology, Science and Research Branch, Islamic Azad University,
Tehran, Iran
2 Department of Cereal Research, Seed and Plant Improvement Research Institute (SPII), P.
O. Box 31585-4119, Karaj, Iran
E-mail Address of presenting author: fallahisomaiea@yahoo.com
Septoria leaf blotch (Septoria tritici blotch: STB) caused by the ascomycetous fungus Mycosphaerella
graminicola (anamorph: Septoria tritici) is one of the most devastating foliar
diseases of wheat in many parts of the world, especially in areas with high rainfall where
heavily fertilized plants show dense foliage. Recent severe epidemics of STB in Iran have
led to extensive fungicide applications in the country. Nevertheless, disease management
relies mainly on successful strategies of breeding for resistance which depends on primary
data of genetic diversity of the pathogen population and their virulence in infected areas.
To study the genetic diversity of M. graminicola, 23 strains were isolated from wheat
leaves with STB symptoms sampled in wheat fields from different locations in Iran. All
isolates were individually inoculated on 20 differential wheat cultivars each carrying one
or more Stb resistance genes in seedling stage under greenhouse condition. Virulence
was visually assessed at 21 days post inoculation (dpi) by evaluation of the leaf necrotic
surface covered with pycnidia. The fungal pathotypes were differentiated based on their
virulence on cultivars and the related Stb gene/s. None of the isolates showed virulence
on cultivar TE 9111 carrying Stb11. Three isolates proved to be the same pathotype by
showing the same virulence pattern on Stb genes, whereas other isolates showed different
virulence patterns on wheat differential cultivars. In this study, 21 M. graminicola
pathotypes were identified which demonstrates a high genetic diversity amongst Iranian
M. graminicola populations.
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