in order to evaluate the competitive ability (ca) of canola cultivars against wild mustard, two experiments were conducted at the gorgan institute in iran during the 2005-2007 cropping seasons. the experimental factors were canola cultivars (1st year: zarfam, option500, hayola330, hayola401, talayh, rgs003 and sarigol; 2nd year: zarfam, hayola330, rgs003 and option500) and weed density (1st yea...