Study on Dielofop-Methyl Resistance in Wild Oat(Avena Ludoviciana): A Comparison Between the Whole Plant and the Seed Bioassays

In order to investigate the resistance of wild oat populations to diclofop-methyl agreenhouse and laboratory experiments were carried out during 2006 . the collected wild oatbiotypes have already shown several cases of resistance to diclofop-methyl in differentlocations in iran. greenhouse experime nts included screening tests and dose responseexperime nts where as, seed bioassay experiment included id50 determination and doseresponse experi ments. the treatments consisted of wild oat popul ations included fr fr2,fr3, fr4, collected from fars provi nce, mr mr2, mr3, collected from markazi province,kr kr2, kr3, collected from khuzestan province and s, collected from a location whichhad never been treated previously with any graminicide. results indicated that kr kr2 andkr3 popu lations showed resistance to diclofop-methyl according to whole plant and seedbioassay trials. resistance ratios tested populations were different and ratios that obtained atseed bioassay were lower than those obtained at whole plant assay . it is also concluded thatthe seed bioassay could be used as a simple, comparatively rapid, inexpensive and accuratemethod for identifying wild oat populations resistant to acetyl coa carboxylase inhib itors