ERGOT RESISTANCE IN SORGHUM IN RELATION TO FLOWERING, INOCULATION TECHNIQUE AND DISEASE DEVELOPMENT

Ergot is an important disease of sorghum (Sorghum bicolor) in parts of Africa and Asia. Studies were conducted to determine the relationship between flowering biology and ergot infection, and to develop an arti ficial field-screening technique to identify ergot resistance in sorgh um. Spikelets resisted infection after anthesis, but each day's delay in anthesis after inoculation supported 8.3% more ergot. The screening technique consisted of three components: trimming of panicles to remo ve pollinated spikelets before inoculation, a single inoculation of tr immed panicles, and panicle bagging for 7-10 days. Inoculated panicles were evaluated by a qualitative visual rating method (on a 1-5 scale) and a quantitative spikelet counting method. Selected accessions from the world collection of sorghum germplasm were screened at Karama Res earch Station, Rwanda, for two seasons and 12 ergot-resistant lines we re identified. These were also resistant at ICRISAT Centre, India.