Mutation breeding in ornamentals: An efficient breeding method?

Scientific interest in mutation breeding has drastically decreased during the last 15 years. Interest in research has shifted towards development and application of molecular techniques as tools in breeding and transformation of plants. Such strategies allow a more directed approach in pursuance of the breeding goal. Molecular techniques, however, generate high developmental costs and require sophisticated equipment and a highly trained staff. The investment in such expensive methods does not seem adequate in case of many ornamental species with their limited economic importance as compared to agricultural crops and their sometimes very short marketing periods in consequence of permanent demand for new fashionable products. In addition, genetically modified ornamental plants are not marketed in Europe at the time being due to low acceptance of consumers and the uncertain legal situation. On the other hand, ornamental plants appear to be ideal systems for mutation breeding as many characters of economic interest, i.e. flower traits or the growth habit are easily monitored after mutagenic treatment. Furthermore, many ornamental species are heterozygous and often propagated vegetatively thus allowing the detection, selection and conservation of mutants within the M1-generation. Appropriate strategies in mutation induction as application of fractionated doses and recurrent irradiation combined with in vitro culture techniques may lead to rapid success also in homozygous, polyploid species. Inspite of its accidental character, mutation induction continues to be an attractive method for creating genetic variability in ornamentals whenever the desired characters can be expected within the genetic scope of a given species. Practical mutation breeding nowadays has become a routine technique in many vegetatively propagated ornamental plants and is being used by commercial breeding companies.