3.1. Choice of Mutagen
A long held notion, which probably has been influencing the choice of mutagen types (chemical vs. physical), is that chemical mutagens preferentially induce point mutations while physical mutagens induce gross lesions, such as chromosomal breakages and rearrangements. This view has probably been aided by the relative ease for procuring chemical mutagens as well as simpler set-up requirements. Current empirical data do not support this conclusion; rather the more plausible inference from available information is that the frequency and types of mutations are direct results of the dosage and rate of exposure or administration of the mutagen rather than its type. This implies therefore that the extended immersion of plant propagules in high concentrations of EMS or NaN3 would be equally as deleterious or even lethal as extended exposures to high doses of ionizing radiation. In all cases, optimal doses of mutagens should always be determined prior to large-scale induction of mutations. It should also be pointed out that chemical mutagens are very toxic poisons that usually require elaborate detoxification of laboratory ware and disposal of used reagents. Relatively, the risks to health posed by physical mutagens are far less. In the end, the choice of a mutagen will be based on the particular researcher’s circumstances such as the availability of the mutagens, associated costs and available infrastructure.