Success Story of Induced Mutagenesis for Development of New Ornamental Varieties

Induced mutagenesis is well recognized as one of the most important technology for the development of new varieties through genetic manipulations. Mutation techniques, using physical and chemical mutagens, have successfully produced quite a large number of new promising varieties in different ornamental plants. This technique has been most successful in ornamental plants due to some additional advantages. Changes in any phenotypic characteristics like colour, shape or size of flower and chlorophyll variegation in leaves can be easily detected. Heterozygous nature of many of the cultivars offers high mutation frequency. The main advantage of mutation induction in vegetative propagated crops is the ability to change one or a few characters of an otherwise outstanding cultivar without altering the remaining and often unique part of the genotype. Voluminous literature for successful application of classical induced mutagenesis have been generated on radio-sensitivity, selection of materials, methods of exposure to gamma rays, suitable dose, detection of mutations, mutation frequency and spectrum, isolation of mutants and commercial exploitation of mutants. Different treatment methodology like recurrent irradiation, combined treatment, split dose, colchicine treatment, ion beam technology, space breeding, TILLING, EMAIL, etc., have been precisely determined for successful development of new varieties. The main bottlenecks in mutation breeding of vegetatively propagated plant are formation of chimeras. Therefore, attempts were made to find out the ways to overcome this situation. Management of chimera and in vitro technique have opened a new way for isolating new flower colour/shape ornamental cultivars through retrieval of mutated cells. Step wise advancement/refinement of practical approaches for application of classical induced mutagenesis and recent techniques for improvement of ornamental crops have been highlighted. _____________________________________________________________________________________________________________