Influence of Some Nitrogen and Carbohydrate Sources on Growth, Sporulation and Pathogenicity of Bipolaris Species

Abstract

Isolates of Bipolaris sacchari and B. australiensis that had been isolated from stem base and roots of wheat grown in Hamadan province, have shown tendencies to give a differential pathogenic response when used to inoculate the root and foliage of several cereals including barley and wheat cvs. They grew well on a number of inorganic and organic nitrogen and carbohydrate sources. There was some evidence of a differential pathogenicity of B. sacchari and B. australiensis on wheat and barley, with inoculums grown on media containing argenine produced less leaf and stem-base lesions on barley and wheat cultivars in comparing with others, even the control. In the case of B. australiensis, the most pathogenic response on foliage and stem-base occurred with inoculums grown on peptone, whereas in the case of B. sacchari inoculums grown on media containing galactose and glucose were more effective. All nitrogen and carbon sources tested, supported some growth with the possible exception of Arginine and asparagines. Maximum growth of fungal colony occurred on peptone as well as mycelium dry weight on media containing glucose and cellubiose.