Wheat is the most important crop in the world in terms of area harvested (220 million hectares in 2014). The main types of cultivated wheat are the hexaploid bread wheat, and tetraploid durum wheat. Other types of wheats, such as einkorn, emmer, spelt and kamut, are still grown in some regions.
The earliest forms of domesticated wheat originated in Southeast Turkey. From there, the crop spread to the Near East, with hexaploid forms first appearing there 9,000 years ago. The dispersal of the crop into Europe occurred through Greece (8,000 BP). It reached the Balkans, the Danube, and southern Europe by 7,000 BP. Wheat was brought to China through Iran and Central Asia (3000 BP), and it entered Africa through Egypt. Later, the Spanish introduced the crop to Mexico in the 16th century.
Wheat is expected to be negatively impacted by climate change. Due to its importance in diets and livelihoods, a global effort led by [CIMMYT] (http://wheat.org/) is harnessing the genetic diversity of wheat to produce more resilient, productive and nutritious varieties.