All wheat belongs to the genus Triticum. From that classification wheat can be divided into three groups based on their number of chromosomes. Diploid wheat (14 chromosomes) is the earliest grouping. Cultivated varieties in this group are rare and very unusual. The only example that was known to be cultivated is einkorn. Einkorn was cultivated by the ancient Egyptians and has been found in 4000 year old tombs of the Pharaohs.
Tetraploid wheat (28 chromosomes) is more common. This includes ancient varieties such as emmer and khorasan Triticum turgidum ssp.turanicum (sold as KAMUT® brand wheat) as well as modern varieties such as durum. Durum is most commonly used to make pasta. The most common wheat is hexaploid wheat (42 chromosomes) and includes spelt, modern bread wheat and soft wheat used for cookies and cakes.
Wild tetraploid wheat was thought to have occurred mostly in the Near East where it was first gathered by man. Varieties in early agriculture were not pure lines, but consisted of a mixture of closely related grain lines called land race varieties. This is in contrast to the varieties of single lines that occur today with modern agriculture. The diversity of these land races gave protection against attacks of disease or insects. If one strain was susceptible to an attack, other strains could be resistant and the whole crop would not be lost. The khorasan wheat which is grown today and sold under the KAMUT® brand name is a heritage grain and of a land race containing this same diversity and advantage of ancient land races.