Durum wheat and Wheat

Durum wheat noun - Wheat with hard dark-colored kernels high in gluten and used for bread and pasta; grown especially in southern Russia, North Africa, and northern central North America.

Wheat and durum wheat are semantically related. In some cases you can use "Wheat" instead a noun phrase "Durum wheat".

Wheat noun - Annual or biennial grass having erect flower spikes and light brown grains.

Durum wheat and wheat are semantically related. Sometimes you can replace phrase "Durum wheat" with "Wheat", this terms are similar.