Buckwheat and Food grain

Buckwheat noun - Grain ground into flour.

Food grain and buckwheat are semantically related. In some cases you can use "Food grain" instead a noun "Buckwheat".

Food grain noun - Foodstuff prepared from the starchy grains of cereal grasses.

Buckwheat and food grain are semantically related. Sometimes you can replace term "Buckwheat" with "Food grain", this terms are similar.