POLLEN DISPERSAL ABILITIES OF ALS TARGET-SITE RESISTANT BLACK-GRASS (ALOPECURUS MYOSUROIDES HUDS.)

Target-Site Resistant (TSR) black-grass individuals were introduced in a field, at different growing stages to be synchronised with autochthonous population. Patches of susceptible black-grass were created by setting protective canvas on few areas (from 0,5 up to 32m²), during herbicide spraying and they were removed afterwards. Those patches were disposed along rays starting from the introduction point at distances from 2 to 128 meters. In those patches, local black-grass grew regularly and was able to receive some pollen from the resistant individuals, located in the centered emitting area. The herbicide field treatment (mesosulfuron+iodosulfuron : 15+3 g.a.i.ha-1) was efficient, confirming that the local population is susceptible to ALS inhibitors, was preceded by another herbicide treatment targeting only broad-leaves weeds, performed on the entire field, including patches, such as the rest of cultural practices such as fertilization, and fungicide and insecticide treatment. All seeds were harvested in each patches separately and tested in glasshouse. Seed samples were sprayed with sulfometuron, herbicide active ingredient known not to be affected by non-target site resistance, in a way to detect the percentage of resistant black-grass that can be engendered after the introduction of TSR individuals and to determine the distance resistant pollen can cover. DNA analyses were performed on surviving plants to confirm the presence of the mutation.