Fusarium head blight resistance in Aegilops tauschii

Fusarium head blight (FHB), caused by Fusarium graminearum Schwabe [telomorph = Gibberella zeae (Schw.) Petch], is a persistent threat to wheat production. Development of resistant varieties and identification of germplasm carrying new sources of resistance is necessary to preserve grain quality and yield. Resistance to FHB has been identified both within the gene pools of cultivated wheat and wild wheat relatives. In this study, a collection of the D genome species, Aegilops tauschii Coss. was evaluated for resistance to FHB. A total of 109 accessions of Ae. tauschii Coss. subsp. tauschii and Ae. tauschii Coss. subsp. strangulata (Eig) Tzvelev were infected with F. graminearum by single floret inoculation. Disease severity was rated as the percentage of infected spikelets at 21 days post-inoculation. A strong relationship was identified between geographical origin of Ae. tauschii accessions and FHB resistance. Generally, accessions from areas receiving high levels of annual rainfall were resistant whereas accessions from areas of low rainfall, more susceptible to FHB. High levels of FHB resistance were identified in accessions collected from regions bordering the Caspian Sea. The majority of accessions from arid regions were susceptible to FHB. The resistant germplasm identified in this study will support long-term FHB resistance breeding efforts.