There are four main types of wheat blending:

1. Blending of different varieties of the same wheat species, such as hard red winter and soft white spring wheats.
2. Blending of different species of wheat, such as hard red winter and durum wheats.
3. Blending of different classes of wheat, such as bread and durum wheats.
4. Blending with other grains, such as oats or rye to create a multi-grain flour blend.

Wheat blending is often used to create flours with specific characteristics, from texture and flavor to nutritional content and baking performance.