In addition to the ionizing radiations, the other commonly used physical mutagens are the high energy ionizing particles, alpha (α) and beta (β) particles and neutrons. The properties of physical agents that are used in inducing crops to mutate are summarized in Table 2. The mutagenicity of these agents derives from a combination of their ability to produce dimmers and reactive ions which in turn cause damage to living organisms; the damage caused ranges from aberrations at the DNA level (breaking the chemical bonds in DNA molecules, deleting or adding nucleotides and by substituting one nucleotide for the other) to gross chromosomal breakages and rearrangements.