It is composed of large cells, mostly inactive, filled with starch grains. This is the part that supplies sugar to the germinating seed for energy and for synthesis of all cell components. The embryo is the young plant of the new generation, the product of the developing zygote. This is commercially known as the germ, and is rich in proteins, vitamins, and oil. The bran consists of the outer layers of old fruit wall, seed coat, and aleurone layer.
Most layers are fibrous and contain little of nutritious value.
Milling of grain separates the parts. Whole-grain products are more nutritious mostly because of the presence of the germ or embryo. Adapted to cool dry climate, 12-36 in. rain per year. Durum wheats descended from emmer. Used for pasta, noodles.