Subclasses are soft white, white club and western white. SRW is used for cakes, pastries, flat breads, crackers and snack foods. This fall-seeded wheat comprises about fourteen percent of U.S. wheat exports. There are no subclasses of this class. Durum, the hardest of all U.S. wheats, provides semolina for spaghetti, macaroni and other pasta products.
Durum comprises nearly five percent of total U.S. wheat exports.
Subclasses are hard amber durum, amber durum and durum.