Yield Losses in Sorghum Due to Covered Kernel Smut in Northeast Ethiopia

Abstract

A study to determine yield losses in four cultivars of sorghum (Sorghum bicolor) due to covered kernel smut caused by Sporisorium sorghi was made at Sirinka and Kobo, both located in Northeast Ethiopia, during 2001 and 2002. Seeds of cultivars Jigurty, Gambella 1107, 76Ti#23 and Meko were artificially inoculated with teliospores of covered kernel smut. The control treatment was protected from the disease using fungicide. Different levels of covered kernel smut infection were produced among the cultivars in the inoculated plots, causing significant grain yield reductions. At Kobo, higher grain yield reduction (40.2%) occurred in 2001 when
disease incidence was 32.6% and severity 4.7 than in 2002 (12.9%) when disease incidence was 35.0% and severity 3.2. Similarly, at Sirinka, higher yield reduction occurred in 2001 (9.9%) at 4.0% disease incidence and 2.8 severity than in 2002 (7.8%) at mean disease
incidence of 20.5% and severity of 2,5. There were highly significant positive (p < 0.05) correlations between covered kernel smut severity and grain yield losses. The findings indicated that grain yield was highly influenced by disease severity. The levels of yield loss
were found significant enough to justify control of the disease.