Modification of mutagenic efficiency of ethyl methanesulfonate with ethidium bromide, iodoacetamide and sodium fluoride in barley

Abstract In order to modify the cellular sieves through which a pre-mutational lesion must pass before it can be realized as a phenotypic change, barley seeds were treated with ethyl methanesulfonate (EMS) in combination with non-toxic concentrations of ethidium bromide (EB), iodoacetamide (IA) and sodium fluoride (NaF). Treatments with EMS, EB, IA and NaF alone served as controls. Pre- and post-treatments with the modifying chemicals were also investigated. Seeds treated with EMS and three different modifiers served as the various controls. The parameters considered were germination, seedling injury, plants with chlorophyll chimeras, mitotic and meiotic aberrations, pollen sterility and seed set in M 1 and the frequency of chlorophyll mutations in M 2 . None of the modifiers at the concentrations used, induced chlorophyll mutations in M 2 . However, the presence of EB, IA and NaF at the same concentration during treatments with EMS, significantly enhanced the mutagenic effect of the latter. Pre- and post-treatment with IA also significantly enhanced the mutation frequency in M 2 seedlings. Pre- and post-treatments of EB and NaF did not bring about significant alterations in the mutation rates.