Farmers may have domesticated wheat without meaning to
Wild wheat ears shatter when ripe, scattering their grains. Stalks with tougher ears held on until harvest, so each season early farmers unknowingly resowed more of them. That accidental selection produced a crop so dependent on people that modern wheat can no longer survive in the wild.
Hunter-gatherers in West Asia gathered wild wheat for thousands of years, possibly from 21,000 BC, before cultivation began in the Fertile Crescent around 9600 BC. Einkorn was tamed in southeastern Anatolia, apparently in several places, with the first domestic grains appearing after about 8800 BC at sites such as Çayönü. Emmer, first grown in the southern Levant, was domesticated once. Barley dominated the earliest farms, and wheat became a staple only after about 8500 BC, grown with little labour by fencing out grazing animals and resowing harvested stands.
Its genetics are a tangle of ancient mergers. Einkorn carries two sets of seven chromosomes. Wild emmer arose when two wild grasses hybridised long before farming, doubling the count to four sets, and durum descends from it. Bread wheat came later, when emmer crossed with a goatgrass in farmers' fields to form a six-set hybrid; DNA from seeds at Çatalhöyük shows such wheat existed by around 6400 BC. The earliest wheat with enough gluten for yeasted bread so far was stored around 1350 BC in a Macedonian granary at Assiros.
The grain travelled fast. Emmer reached Cyprus by 8600 BC, Greece by 6500 BC and Egypt soon after 6000 BC, where bakers developed ovens and some of the first large-scale food production. Britain and Scandinavia had wheat by 4000 BC and China's lower Yellow River by about 2600 BC. After 1860, expanding American harvests cut world prices by 40 percent, making white bread, once a mark of status, everyday food.
No food crop is planted over a wider area: in 2024 wheat occupied 219.5 million hectares, and trade in it exceeds that in all other crops combined. Roots reach 2 metres deep, and the topmost flag leaf does much of the work of filling the grain. Oddly, the plant carries more breathing pores on the upper surface of its leaves than underneath.
Source: Wheat
