Weed resistance to herbicides is one of the major barriers to agriculture worldwide. In Brazil, Euphorbia heterophylla (EPHHL) is especially known for presenting resistance to more than one herbicide action mechanism. This work was carried out to identify morphophysiological characteristics and ecological adaptability between Euphorbia heterophylla biotypes with multiple resistance to ALS inhibitors and PROTOX, and with resistance only to ALS inhibitors and susceptible from Southwestern Paraná. The experiment was conducted in a greenhouse and arranged in a completely randomized design, with four replications. The morphophysiological characteristics evaluated were: dry matter of leaves + cotyledons, roots, stems+petioles and total, plant height, number of branches per plant, leaf area and number of leaves per plant. In determinations made at a later time, biotype S presented smaller dry matter of leaves+cotyledons, stems+petioles and total, as well as smaller leaf area, number of leaves per plant and height than biotypes R to ALS and R to Protox.
adaptability; competition; biological behavior; height; wild poinsettia
