The common wheat planted now is formed by two natural distant hybridization of three wild plants and more than 9000 years of natural selection and artificial selection. The earliest wheat planted by human beings is called a wheat, and the yield of a wheat is very low; After that, there were two wheat grains, which were produced by the natural distant hybridization between a wheat grain and Spielbert goat grass. Two grains of wheat have high yield and gradually replace one grain of wheat. Ermai met another weed called Aegilops tauschii in the field. The oldest common wheat was formed by cross dyeing of Ermai and Aegilops tauschii. After more than 5,000 years of natural selection and artificial selection, the common wheat we planted today was formed.