The use of Cochliobolus sativus culture filtrates to evaluate barley resistance to spot blotch.

Arabi M. I. E. & Jawhar M. (2012) The use of Cochliobolus sativus culture filtrates to evaluate barley resistance to spot blotch.

Sydowia 64 (1): 13–18

Spot blotch (SB) caused by Cochliobolus sativus is a serious foliar disease that is particularly important in areas that are warm and moist during the barley growing season. In this study, the potential was assessed for using culture filtrates from potato-dextrose broth cultures of C. sativus in a fast, effective screening pro-cedure for SB resistance in barley. The C. sativus culture filtrates were capable of eliciting SB symptoms on leaves as observed under field conditions, and no clear-cut distinction could be made between leaf symp-toms produced by the culture filtrates and by the pathogen itself. Control plants treated with un-inoculated potato-dextrose broth or autoclaved water did not develop symptoms. A high correlation coefficient between the percentage of the leaf area infected (LAI) by C. sativus and the percentage of the necrotic leaf area (LAN) by the culture filtrate was observed (r = 0.94, P < 0.001). The established method using culture filtrates enables a fast assessment of the resistance of barley to SB and should be useful for many types of studies on this disease.

Keywords: Bipolaris sorokiniana, Hordeum vulgare, resistance test.