Abstract

A potential source of resistance to septoria nodorum blotch had been identified in an accession of the wild wheat, Aegilops tauschii. A cross was made between the resistant Ae. tauschii accession, AUS21712, and a susceptible accession, CPI110889, to study the genetics of resistance. The parental accessions and the F₁, F₃, and F₄ progeny were screened in the glasshouse as seedlings. The resistant parent took significantly longer to develop symptoms, developed significantly fewer lesions, and expressed significantly lower levels of disease than the susceptible parent. The F₁ mean response for disease severity indicated resistance was dominant. The genotypic ratios generated from the screening of the F₃ and F₄ generations were not significantly different from the genotypic ratio expected for a single gene. The efficacy of the resistance and its simple genetic control in the Ae. tauschii accession AUS21712 means that the potential exists to use this Ae. tauschii resistance gene in a bread wheat breeding program.