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The effects of the herbicides 2,4-dichlorophenoxy acetic acid and isoproturon on 3 wheat (Triticum aestivum L.) varieties (HUW 234, HUW 468, and HUW 533) were studied with regards to mitotic abnormalities and chromosomal behavior. Pre-soaked seeds were treated with both herbicides at concentrations of 50-1200 ppm. Both 2,4-D and isoproturon were highly mito-inhibitory and induced chromosomal abnormalities, such as precocious movement, stickiness, and chromosome bridges, with and without laggards and fragments at the anaphase and telophase. The frequency of chromosomal anomalies in almost all the targets used was high at the maximum dose of both herbicides, individually as well as in combination. Isoproturon was more toxic, as it resulted in high-level chromosomal damage in all the varieties. Both herbicides had a dose-dependent impact on the mitotic index (MI) and relative abnormality rate (RAR). These parameters collectively indicate that variety HUW 468 was more susceptible to the mito-depressive and chromotoxic action of the 2 herbicides. [ABSTRACT FROM AUTHOR]