Plant cell and tissue culture methods are useful for mutation induction with radiation as well as chemicals. However, radiation is the preferred method to make genetic changes because of the ease in treating large populations, and the problems of handling and disposing of chemicals. Usually, mutations are induced in well-known and well-adapted plant varieties grown in a particular region. Selected and disease-free plants of these varieties are cultured in vitro, and irradiated with gamma, UV and X-rays. The irradiated plants, tissues, or cells are then multiplied many times, in vitro, from...