Induction of mutations for cytoplasmic male sterility and some rare phenotypes in Indian mustard (Brassica juncea L.)

Four chemical mutagens, ethyl methane sulfonate (EMS), ethidium bromide (EBr), ethyl nitroso urea (ENU) and streptomycin were used to induce mutations in Brassica juncea. EMS and EBr were found to be highly efficient and yielded mutants for all the traits examined. Ninety seven mutants were recovered in the M₂ generation of 800 families. Several novel mutations such as terminal flower, tri-and tetra-locular siliqua, multiple anthers and non-shattering pods were obtained and have been described. In addition, agronomically valuable mutants such as yellow seeds and cytoplasmic male sterility have been isolated. Almost all these mutations were recessive, although some of them appeared in M, generation itself. The results show that mutagenesis is still relevant in polyploid species. Ethidium bromide, in particular, appears to be a very potent mutagen for Brassica.