Tracing resistance of wild mustard (Sinapis arvensis L.) to Tribenuron methyl and evaluation of relative fitness of its susceptible and resistant ecotypes in Eslamabad-Gharb, Kermanshah

This study was conducted to determine the resistance, as well as the effect of temperature, drought and acidity on the relative fitness of wild mustard ecotypes. Sampling was performed from 313 rain-fed wheat farms in Eslamabad-Gharb located in Kermanshah. After sowing the seeds in the greenhouse, the seedlings were treated by the recommended dose (15 g.a.i.ha-1) of Tribenuron methyl (granstrar) 75% WP in the 2-4 leaf stage and sensitive and resistant ecotypes of wild mustard were identified. The results of dose-response test (Tribenuron methyl concentrations: zero, 3.75, 7.5, 15, 30, 60, 120, 240, 480 g.a.i.ha-1) showed that the amount of LD50 in the susceptible and the resistant ecotype were 22.2 7 and 39.85 g.a.i.ha-1, respectively and the resistance index was 5.52 resistant ecotype. Susceptible ecotype at 20 and 25 ° C had higher germination percentage and vigor than resistant ecotype. In general, wild mustard was sensitive to reduction of soil osmotic potential, but the sensitivity of the resistant mass was higher than the susceptible ecotype. The highest germination percentage in both susceptible and resistant ecotypes was observed in slightly acidic to neutral pH (6 to 7) that the germination percentage of resistant ecotypes in this range was significantly higher than the susceptible ecotype. Considering the temperature conditions, drought stress of rain-fed fields and also the alkalinity of the soil in the study area, it seems that if the pressure caused by herbicide application is relieved, the susceptible ecotype will have more fitness to environment condition of studied region.