Induction of maize chromosome altered plants by seeds irradiation pre-soaked in metronidazole

Mutation induction by gamma radiation has been used to obtaining plants with chromosome alteration. However, most times the use of higher dosages makes unfeasible the survival of the mutants and consequently their perpetuation. The use of radiosensitizing compound allows that smaller dosages can be applied increasing the chances of mutants survival. In this work we verified the radiosensitizing effect of metronidazole through cytogenetical analysis and its potentiality to produce plants with chromosome alterations without viability loss. Maize seeds were pre-soaked in five concentrations of metronidazole and then submitted to four radiation dosages. Part of the seeds was used for cytogenetical analysis and another planted for survival analysis to obtain M2 seeds. Cytogenetical analysis showed a radiosensitizing effect of metronidazole mainly in the dosages of 30 and 60 Gy. At 90 Gy, the harmful effect of the radiation hindered the analysis of the radiosensitizing effect. The alterations found in M1 reappeared in M2, indicating that those abnormalities are not in their totality due to somatic origin. The use of a radiosensitizing compound can be useful tool for mutant production in plants.