Three primary types of sunflower are grown: (1) oilseed for vegetable oil production, (2) nonoilseed for human food and bird food markets and (3) Conoil, which can be used for the dehull confection, oil or bird food markets. The oilseed hybrids may be of three fatty acid types: linoleic, mid-oleic (NuSun) or high oleic. They are usually black seeded and have a thin hull that adheres to the kernel. Seed of the oilseed varieties contains from 38% to 50% oil and about 20% protein. Some black-seeded oil types go into the hulling market for birdseed. Nonoilseed sunflowers also has been referred to as confectionery sunflower, and seeds usually are white striped and large. Nonoilseed sunflowers generally have a relatively thick hull that remains loosely attached to the kernel, permitting more complete
dehulling. Seed of the nonoilseed hybrids generally is larger than that of the oilseed types and has a lower oil percentage and test weight. Sunflowers are a major source of vegetable oil in the world.