Chapter 12 - Influence of gamma radiation on maize (Zea mays) starch granules morphology

The starch is the main source of energy for the most people in the world, and it is widely used in many industries. In most cases the only way to modify the starch composition and content is by using chemical or physical mutagens in order to meet the specific industrial needs. The particular properties of starch are based mainly on the amylose/amylopectin ratio and number of small and large granules. Mutagenesis (both chemical and physical) is a powerful tool that helps the breeder to develop new plant varieties with altered starch composition and content. Last but not least, the use of mutagenesis can significantly enlarge the diversity of initial plant material. This is especially important for maize for at least two reasons – firstly the inbred lines are the ‘key to success’ in breeding the cross-pollination species, and secondly, maize is the main source of starch for most of the world. Technology professionals pay special attention to the waxy maize (amylose content less than 2%) starch, as well as to other waxy cereal (wheat, barley, millet) starches, because of the desirable properties of amylose-free starch. In this context, developing new inbred maize lines is relevant. In this chapter results of breeding a new maize amylose-free line, developed from F 3 mutant population after gamma irradiation at 100 Gy are presented. This mutant line is different from the original line by the colour of grain and relationship among small and large starch granules in seed. This line is provided for use in the Ukraine National Breeding Programme to produce amylose-free hybrids and registration in the National Center of Plant Resources of Ukraine.