عنوان مقاله [English]
نویسندگان [English]چکیده [English]
In order to identify fungi involving root and crown rot of wheat and to determine their distribution and frequency, wheat fields in different regions of Kermanshah province were sampled at seedling, tillering and heading stages during 2004-9. For isolation of fungi, some samples of infected roots, subcrown internode, crown and foot were surface sterilized and then placed on potato dextrose agar containing streptomycin sulfate. Pathogenecity test was performed by mixing of pasteurized soil with inoculum (colonized wheat seeds with an isolate) under greenhouse condition. Disease severity (D.S.) was evaluated by scoring from 1 to 5 (1= no symptoms, 5= extensive necrosis of the crown and stem base resulting in plant death). Besides other genera, 241 isolates of Fusarium spp.were isolated. Also the results revealed that Fusarium spp. exist in most parts of the province and their D.S. are from 1 to 2.9.Among Fusarium species Fusarium culmorum and F. pseudograminearum had the highest D.S., F. acuminatum, F.avenaceum, F. crookwellense, F. proliferatum and F. udum had medium D.S. and that of F. nygamai, F. reticulatumand, F. merismoides was the least amount. The species that could not cause disease were F .equiseti, F. lateritium, F. moniliforme, F. oxysporum, F. sambucinun, F. semitectum, F. solani and F. trisinctum. This is the first report of pathogenicity of F. udum, F. nygamai and F. merismoides on wheat root in the world.