Stem Rust, Tan Spot, Stagonospora nodorum Blotch, and Hessian Fly Resistance in Langdon Durum–Aegilops tauschii Synthetic Hexaploid Wheat Lines

Diseases and pests of wheat (Triticum aestivum L.) cause serious yield and quality losses to wheat grown worldwide. In the current study we tested synthetic hexaploid wheat (SHW) lines developed from various lines of Aegilops tauschii Cosson crossed with the tetraploid durum wheat (T. turgidum L.) cultivar Langdon. These SHW lines were tested along with their durum wheat and A. tauschii parents for resistance to stem rust (caused by Puccinia graminis Pers.:Pers. f. sp. tritici Eriks. and E. Henn.), tan spot [caused by Pyrenophora tritici‐repentis (Died.) Drechs.], and Stagonospora nodorum blotch [SNB; caused by Phaeosphaeria nodorum (E. Mull.) Hedjar] as well as for resistance to Hessian fly [Mayetiola destructor (Say) (Diptera: Cecidomyiidae)]. Langdon durum and all SHW lines were resistant to all races tested for stem rust. Although the durum parent Langdon was susceptible to tan spot, SNB, and Hessian fly, resistance was identified in several synthetic lines for each disease or pest indicating that the A. tauschii lines used in constructing the SHW lines are potentially useful sources of resistance. These resistant SHW lines are presently being used to characterize new sources of the resistance and introgress the resistance into bread wheat.