Bread wheat is academically called common wheat with a Latin name as T. aestivum, is a widely cultivated allohexaploid (2n = 6x = 42, AABBDD). It formed ∼8000 years ago as a hybrid between an early-cultivated allotetraploid and a diploid species.
T. turgidum ssp. dicoccoides Thell is also named Triticum dicoccoides sometimes. It is a tetraploid wheat with 28 chromosomes (2n = 4x = 28, AABB). It is considered to be the wild form of all domesticated emmer wheats, i.e. wild emmer wheat (WEW).
Aegilops tauschii (2n=2x=14, DD) is the diploid progenitor of the D genome of hexaploid wheat (Triticum aestivum, genomes AABBDD) and an important genetic resource for wheat.
The initial domestication of the allo-tetraploid wild emmer wheat [WEW; T. turgidum ssp. dicoccoides (Körn.) Thell.; genome BBAA] and the subsequent evolution of hulled domesticated emmer wheat (DEW; T. turgidum ssp. dicoccum Schrank) led to the selection of free-threshing durum wheat [T. turgidum ssp. durum (Desf.) MacKey, or DW].
Triticum urartu (diploid, AA, 2n=2x=14) is the progenitor of the A subgenome of tetraploid (Triticum turgidum, AABB) and hexaploid (Triticum aestivum, AABBDD) wheat.