Why can wheat grow all over the world?

             Unlike rice, wheat today is grown all over the planet because it can adapt to a wide range of climatic conditions. It needs little water and is able to withstand relatively low temperatures. Human beings have been using wheat for over 10,000 years. During this period the plant has developed great genetic diversity, which is why this particular cereal is so adaptable. Two particular wheat genes are responsible for a large part of this diversity-the VRN1 and VRN2 genes. These control growth are reproduction, and determine when the plants are to flower. The VRN2 gene, for example, suppresses the production of flowers in winter wheat and so protects the plant form frost damage.