Greenhouse and laboratory studies were conducted to evaluate the effects of rye residues on germination and growth of three triazine-resistant weed species, barnyardgrass, willowherb, and horseweed. Soil containing rye roots was used to determine rye residue influence on seed germination. Willowherb and horseweed germination was inhibited up to 50% with the highest rate of rye, but there was no inhibition of barnyardgrass germination. Aqueous extracts of rye shoot tissue inhibited incubator germination of horseweed and willowherb, but did not significantly influence barnyardgrass germination. Although there were no germination differences between the susceptible and resistant biotypes, both were totally inhibited when a 5% w/v solution was used. Growth inhibition of the selected weeds was evaluated using rye root residues in soil. All combinations of biotypes, species, and rye seeding rates showed significant growth inhibition.
