Wheat has been cultivated domestically at least since 9,000 B.C. and probably earlier.
Domesticated Einkorn wheat at Nevali Cori 40 miles northwest of Gobekli Tepe in Turkey has been dated to 9,000 B.C.
Which Came First, Monumental Building Projects or Farming?, Archaeo News, Dec 2008.
At Nevali Cori, a Neolithic village 40 miles northwest of Schmidt's site, archaeologists found seeds of domesticated einkorn wheat dating from 9000 BCE.However domesticated barley has been dated to 23,000 B.C. and some say this is also true of wheat.
Eureka Alert (Aug 2004): Oldest Evidence for Processing of Wild Cereals: Starch Grains from Barley, Wheat, on Grinding Stone.
When the water level in the Sea of Galilee dropped in 1989, archaeologists rushed to excavate Ohalo II, an ancient human settlement. On the floor of one hut they found a large, flat, basaltic stone. The stone's uneven surface yielded starch grains of grass seeds, mostly from wild barley and possibly also from wheat. This evidence presented in the journal Nature (August 5, 2004), pushes back the date for the processing of close wild relatives of domesticated wheat and barley, a key step in cultural development, to 23,000 years before the present era. "Ten thousand years before people were cultivating cereals, they were processing wild barley: starch grain analysis establishes a clear link between an intensive exploitation of wild cereals and the subsequent development of plant cultivation and domestication in the region " explains Dolores Piperno, lead author.Piperno, D.R., et al., Processing of Wild Cereal Grains in the Upper Palaeolithic Revealed by Starch Grain Analysis, Nature, 430, Pages 670-673, Aug 2004
Barley (Hordeum vulgare L.) and wheat (Triticum monococcum L. and Triticum turgidum L.) were among the principal 'founder crops' of southwest Asian agriculture. Two issues that were central to the cultural transition from foraging to food production are poorly understood. They are the dates at which human groups began to routinely exploit wild varieties of wheat and barley, and when foragers first utilized technologies to pound and grind the hard, fibrous seeds of these and other plants to turn them into easily digestible foodstuffs. Here we report the earliest direct evidence for human processing of grass seeds, including barley and possibly wheat, in the form of starch grains recovered from a ground stone artefact from the Upper Palaeolithic site of Ohalo II in Israel. Associated evidence for an oven-like hearth was also found at this site, suggesting that dough made from grain flour was baked. Our data indicate that routine processing of a selected group of wild cereals, combined with effective methods of cooking ground seeds, were practiced at least 12,000 years before their domestication in southwest Asia.It is obvious that corn is over 80,000 years old.