Origins of Wheat
The origins of our modern wheat, according to genetics, are found in the Karacadag mountain region of southeastern Turkey. There, some 10,000 years ago or so, two types of wheat were domesticated: einkorn or Triticum monococcum and emmer (reported both as T. araraticum and T. turgidum ssp. dicoccoides). Spelt, T. spelta, and T. timopheevii were ancient forms of wheat developed by the late Neolithic, neither of which have much of a market today.The main differences between the wild forms of wheat and domesticated wheat are that domesticated forms have larger seeds and a non-shattering rachis. When wild wheat is ripe, the rachis--the stem that keeps the wheat shafts together--shatters so that the seeds can disperse themselves. But that naturally useful brittleness doesn't suit humans, who prefer to wait until the wheat is ripe to harvest it, and so, the theory goes anyway, selected wheats with rachis that didn't become brittle at harvest time.
Wheat in Archaeology
Recent studies in wheat origins include a report of a field experiment on the yield potential of the various forms of wheat; a study on the genetic propensity of wheat to dynamically react to bottlenecks by generating new variations; and a genetic study attempting to discriminate the 'new wheat' of the late Neolithic/Bronze Age, T. timopheevii from emmer wheat.Archaeological evidence for domesticated wheat has been found at several sites in the Fertile Crescent, sites such as Abu Hureyra (Syria), Jericho (West Bank), and Cayönü (Turkey). The oldest evidence for both einkorn and emmer wheats found to date was at Abu Hureyra, in occupation layers dated to 9600 years ago.
Sources
This article on the domestication of wheat is a part of the About.com Guide to Plant Domestications, and part of the Dictionary of Archaeology. Any mistakes are the responsibility of Kris Hirst.
Boscato, Paola et al. In press. Molecular markers for the discrimination of Triticum turgidum L. subsp. dicoccum (Schrank ex Schubl.) Thell. and Triticum timopheevii (Zhuk.) Zhuk. subsp. timopheevii. Journal of Archaeological Science in press.
Doebley, John F., Brandon S. Gaut, and Bruce D. Smith. 2006. The molecular genetics of crop domestication. Cell 127: 1309-1321.
Dubcovsky, Jorge and Jan Dvorak. 2007. Genome plasticity a key factor in the success of polyploid wheat under domestication. Science 316:1862-1866.
Heun, Manfred et al. 1997. Site of einkorn wheat domestication identified by DNA fingerprinting. Science 278:1312-1314.
Miller Rosen, Arlene and Stephen Weiner. 1994. Identifying ancient irrigation: a new method using opaline phytoliths from emmer wheat. Journal of Archaeological Science 21:125-132.
Van der Veen, Marijke and Carol Palmer. Environmental factors and the yield potential of ancient wheat crops. Journal of Archaeological Science 24:163-182.
