Inheritance of Trifluralin Resistance in Green Foxtail (<i>Setaria viridis</i>)

In F 2 progeny, derived from F 1 hybrids, shoot growth of seedlings, measured 4 d after germination, distinguished susceptible (S) and resistant (R) phenotypes. Chisquare values indicated that the F 2 data fit a 3:1 (S:R) ratio for both populations and all trifluralin concentrations in which S and R phenotypes could be differentiated. Results indicate that trifluralin resistance in these green foxtail populations is controlled by a single, nuclear recessive gene. This study is the first to demonstrate recessive gene control of herbicide resistance in a weed species. The highly selfed nature and prolific seed production of green foxtail may have facilitated evolution of the recessive trait.