Physical Mutagenesis in Cereal Crops

Abstract

AbstractThe use of physical mutagens to induce heritable genetic variation in crop plants dates back to the beginning of the twentieth century. While X-rays were the first to be used for mutation induction in plants, gamma-rays have been the most widely used physical mutagen. Currently gamma induced mutations represents 60% of the registered mutant varieties in the Mutant Variety Database of the Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture. Beside gamma and X-rays, other physical mutagens include neutrons, beta particles, alpha particles, protons and ion beam. This chapter introduces the technique of physical mutagenesis with emphasis on gamma-ray and X-ray irradiation of seeds in cereals in the context of inducing genetic variation for resistance to the parasitic weed, Striga. Easy to follow step-by-step protocols are explained including sample preparation, treatment application and post-treatment handling of irradiated seeds. Data collection and graphic illustration are presented to estimate the optimum dose for bulk treatment to determine the radio-sensitivity of cereal crops. The last section briefly explains the development and handling of mutant populations by way of introduction to the rest of this book on mutation breeding in cereals for resistance to Striga.