in vitro evaluation of oilseed rape genotypes against blackleg disease caused by phoma lingam

blackleg disease of oilseed rape, caused by leptosphaeria maculans, is one of the three most important diseases of the plant in iran. it is also considered as one of the most important diseases of oilseed rape worldwide which causes serious yield losses. during 2010 the oilseed rape fields were surveyed at province golestan and plant samples demonstrating suspected symptoms of the disease were collected. isolation, purification and mass-production of the isolates were done at the plant pathology unit of oilnseeds crops research department in karaj. the the isolates were studied based on production of pigments in culture medium pda. employing representative isolate from golestan province, 25 lines and cultivars of oilseed rape were tested against the disease. the well developed and expanded leaves of three- month- old plants were inoculated in central area with the pathogen inoculum, and the diameter of induced lessions was measured. based on the results lines hw101, hw104, and sw104 demonstrated resistance against the disease.