I want to irradiate the seeds of okra(Abelmoschus esculentus)seeds for inducing mutant plants. Kindly let me know how to prepare the seeds for mutation treatment. And I would like to know which physical mutagens(gamma rays/ ion beam/ neutron beam)  or chemical (EMS) are better for inducing mutations in cytoplasmic genes (mitochondrial or chloroplast DNA) of plant cells I mean if I take seeds as mutation material? Thank You.