Successful plant breeding depends on genetic variation in useful traits. Induced mutations (chemical and physical) are effective tools in obtaining new cultivars and broadening the genetic base of crops. About 70% mutant varieties were released directly as mutants while remaining 30% were developed through cross breeding programme where mutants served as a source of desirable alleles (Maluszynski et al., 2000). To date, 2,428 crop varieties have been released through mutagenesis; among them 501 are rice varieties.