Tausch's goatgrass or rough-spike hard grass (Aegilops tauschii) is found in temperate Asia and the Caucasus region. It is the diploid progenitor of the bread wheat (Triticum aestivum) D-genome, providing important evolutionary information for wheat. The bread wheat genome is a hexaploid, resulting from the hybridisation of the wild A. tauschii with a cultivated tetraploid wheat, Triticum dicoccoides. This spontaneous event occured about 8,000 years ago in the Fertile Crescent.