Mutagenesis: Generation and Evaluation of Induced Mutations

Mutation breeding is one of the approaches to enhance the spectrum of beneficial alleles of agronomic and economic significance in crop improvement program. It has been demonstrated in oleiferous Brassica species too. Physical and chemical mutagens were used to isolate mutations for reduced plant height and yield-contributing characters. Wide range of variability for flower morphology has been isolated. Yellow seed coat mutants and their use in crossbreeding program have resulted in the development of high oil content lines. Ethyl methane sulfonate (EMS) has played an important role to tailor fatty acid composition of rapeseed-mustard. Mutations for reduced erucic acid and increased oleic acid have been achieved using EMS. Use of mutations for modified fatty acids in crossbreeding has improved oil quality and seed yield potential. The haploid system was found to be beneficial in Brassica napus for the induction of mutation for herbicide resistance, disease resistance, and oil and meal quality. Mutation breeding has been successfully employed to develop high-yielding varieties. So far 31 high-yielding varieties have been developed and released for cultivation all over the world. Compared to important cereal and oilseed crops, limited work on mutation breeding has been undertaken in rapeseed-mustard. Therefore, efforts need to be strengthened to enhance the wide range of variability for agronomical, morphological, biochemical, and biotic and abiotic stress-tolerant characters and to use them in breeding program to break the yield barriers in Brassica crop species. Analysis of mutant at molecular level would reinforce the understanding on mechanism of mutations in the era of genomics.