A single gene controls resistance to septoria nodorum blotch in the Aegilops tauschii accession AUS21712

A potential source of resistance to septoria nodorum blotch had been identi fied 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 acc essions and the F-1, F-3, and F-4 progeny were screened in the glasshouse a s seedlings. The resistant parent took significantly longer to develop symp toms, developed significantly fewer lesions, and expressed significantly lo wer levels of disease than the susceptible parent. The F-1 mean response fo r disease severity indicated resistance was dominant. The genotypic ratios generated from the screening of the F-3 and F-4 generations were not signif icantly different from the genotypic ratio expected for a single gene. The efficacy of the resistance and its simple genetic control in the Ae. tausch ii accession AUS21712 means that the potential exists to use this Ae. tausc hii resistance gene in a bread wheat breeding program.