Investigating the resistance of wild mustard (Sinapis arvenisis L.) biotypes to tribenuron methyl herbicide in wheat fields of Ramiyan Township

More than twenty years after registration of tribenuron methyl herbicide in Iran, there are reports on its lack of efficacy in controlling broad leaved weeds in wheat fields of Ramiyan Township. To investigate the occurrence of resistance to tribenuron methyl in wild mustard (Sinapis arvensis L.), a series of experiments were conducted at Gorgan University of Agricultural Sciences and Natural Resources in 2016. Putatively resistant wild mustard biotypes were gathered from wheat fields of the Township. A susceptible biotype was also gathered from the fields with no history of spraying. Putative biotypes were first screened with the recommended dose. Then, response of susceptible and resistant biotypes to various doses of tribenuron methyl herbicide was investigated. The results of dose-response assay implied occurrence of resistant to tribenuron methyl in some wild mustard biotypes. Resistance factors of RAM-R-14, RAM-R-27, RAM-R-25, RAM-R-30 and RAM-R-5 were obtained respectively 3.90, 4.10, 3.96, 2.66 and 2.36. Distribution map of fields infested with susceptible and resistant wild mustard biotypes was drawn using geographic information system and it was revealed that the gathered biotypes were observed in the fields which possessed unsuitable cropping pattern and weed management was based on chemical control. The results of the present study may be utilized to implement herbicide-resistant weed management practices as well as prevention of development of these plants to other regions.