The common wheat is hexaploid with 2n = 42 and is derived from three diploid species : (i) AA = Triticum aegilopoides (2n = 14), (ii) BB = Aegilops spelloides (2n = 14), (iii) DD = Aegilops squarrosa. The hexaploid wheat therefore, is designated as AABBDD, the tetraploid (2n = 28) as AABB and diploid (2n = 14) as DD.