Based upon my experiences performing security cooperation duties in the Military Assistance Program (MAP) in Jordan, at a GCC, and at DISAM, I offer some thoughts and comments concerning the SDO/DATT concept.
No. Barley is not wheat at all. Barley and wheat are two different species of cereal grasses belonging to the family Triticeae. Barley does belong in the wheat family, which is, as mentioned, Triticeae, but is of an entirely different species from wheat. The species name for barley is Hordeum vulgare, and the species name for wheat is Triticum aestivum. No doubt either look similar, but both are quite different from the other.
Barley is not as cold tolerant as the winter wheats (Triticum aestivum), fall rye (Secale cereale) or winter triticale (Ã Triticosecale Wittm. ex A. Camus.), but may be sown as a winter crop in warmer areas of Australia and Great Britain. Barley has a short growing season and is also relatively drought tolerant.