Mutagenicity of Selected Chemicals in Soybean Test Systems

Abstract

The use of Glycine max (soybean) in assessment of genetic damage by mutagenesis is rather new. The organism has been employed in three types of studies, viz., leaf mosaicism, tissue culture, and traditional progeny testing. Most of the work has been confined to the first type of system which has proven a very sensitive indicator of several types of genetic alterations produced by mutagens. The system makes use of spots induced on heterozygous or homozygous recessive genotypes which express damage in the form of spots of apparently homozygous or hemizygous origin on heterozygous background and heterozygous spots on homozygous leaves. As discussed later, distinction is possible between the induction of somatic crossing over, duplications, deletions, nondisjunction, and specific point mutations by a single treatment of the seed of selfed heterozygous parentage. Since the investigator uses only the colonies of leaf cells whose primordial ancestors have been treated with the mutagen, and there is minimal competition for these cells for expanding in one or a few layers, the system offers advantages over the progeny test method.