Effects of some systemic fungicides on the chiasma frequencies in Hordeum vulgare

Four systemic fungicides-thiabendazole, fuberidazole, carboxin and oxycarboxin have been tested for effects on chiasmata in barley. All compounds excepting thiabendazole have depressed chiasma frequencies significantly. The source of such a variation could be laid a) fairly very early in development as the treatment was done during the first DNA synthetic period in the seeds or b) much later during development because the compounds are systemic in nature. The observations are likely to be useful in genetic toxicology and in dealing with experimental crop populations.