Winter wild oat (Avena ludoviciana) accessions’sresistance to clodinafop-propargyl herbicide in south of Kerman

To investigate the resistance of wild oat (Avena ludoviciana) accessions collected from wheat fields of Kerman province to clodinafop-propargyl herbicide, whole-plant bioassay pot experiment was performed on 16 winter wild oat accessions (15 suspected and one sensitive accessions) in a research greenhouse in Jiroft, Kerman during 2019-2020. First, the screening test was performed with the recommended dose (1 L/ha) of clodinafop-propargyl (EC 8%) herbicide in a randomized complete block design with four replications. Then, in a dose-response experiment, wild oat accessions were sprayed at 2- to 4-leaf stage with 9 doses of clodinafop-propargyl including 0, 0.25, 0.5, 1, 2, 4, 8, 16, and 32 times of recommended dose for resistant accessions and 0, 0.0625, 0.0125, 0.25, 5) 0, 1, 2 and 4 times of recommended dose for the susceptible accessions. Four weeks after spraying, fresh and dry weights and survival percentage of the plants were measured. According to the results, the resistance of 14 accessions to clodinafop-propargyl was confirmed according to the Adkins and Moss methods. The results of the dose-response test based on the fresh weight showed that F3 (14.3) and R4 (3.9) had the highest and lowest resistance index, respectively. Furthermore, based on the survival, M3 and M4 accessions with 14.1 and 2.4 resistance index showed the highest and lowest resistance level to the herbicide, respectively. Therefore, the first case of wild oat resistant to clodinafop-propargyl was recorded in Kerman province.