The discovery of radioactivity at the end of the nineteenth century played a key role in a series of historical landmarks that would lead to contemporary mutation breeding in agricultural crops. The aim of the earliest experiments was to test the effects of radiation on living organisms beginning with fruit flies. Exposure of plants to X-rays provided the first incontrovertible proof that phenotypic changes could be induced. Chemicals were a second type of mutagen tested from the 1940s and both forms are used today. This chapter is an overview of some of the historical developments that led to the use of mutagenesis in plants, with a focus on barley, a model species for mutation genetics and breeding as well as a major cereal crop. Perhaps the most well-known examples of mutant barley cultivars are Diamant, Golden Promise, and their hybrids.
Keywords: Barley (Hordeum vulgare); Chemical mutagenesis; Mutation history; Radiation mutagenesis.