Analysis of information sources in references of the Wikipedia article "Five Grains" in English language version.
They variously distinguish five, six or nine kinds of grain. The term wu ku or five kinds of grain seems to refer to the oldest classification of grain. It is attributed to the Emperor SHEN NUNG. The ancient commentators enumerated these five kinds as follows: 1.– tao, Rice. 2.– mai, comprising Wheat and Barley. 3.– tsi, Panicum miliaceum, the common Millet. 4.– shu, Panicum miliaceum, glutinous variety. 5.– shu, the Soy bean, Soja hispida. Some commentators have liang, Setaria italica, instead of tsi, others substitute ma, hemp, Cannabis sativa, for tuo, rice.
民人食肉饮血,衣皮毛;至于神农,以为行虫走兽,难以养民,乃求可食之物,尝百草之实,察酸苦之味,教人食五谷