Abstract
Resistance to chlorpyrifos is shown to be a dominant character that segregates as a single locus (Chl). The linkage of Chl with Gpd (coding an alpha-glycerophosphate-dehydrogenase) and Est-2 (coding an esterase which polymorhism was found to be strongly correlated to resistance - See Pasteur and Sinègre 1975). The three genes are located on the same linkage group (linkage group III)