AbstractCrude extracts from maize plants treated with varying concentrations of AAtrex, an s‐triazine herbicide, were tested for the induction of gene conversion in a diploid strain of Saccharomyces cerevisiae heteroallelic at two loci. These extracts were then subjected to analysis by high pressure liquid chromatography (HPLC), and the fractions collected in water, 50% methanol, and 100% methanol were similarly tested. Dose‐dependent convertogenic activity observed in the 50% methanol fractions suggested that the mutagen(s) is recovered in this fract