Status of Sorghum Covered Kernel Smut and Reaction of Some Sorghum Cultivars in Northeast Ethiopia

Abstract

Covered kernel smut caused by the fungus Sporisorium sorghi is the major disease threatening sorghum [Sorghum bicolour (L.) Moench.] production in northeast Ethiopia. The present study was made to assess the distribution, incidence and severity of the disease in the area and to evaluate the reaction of some sorghum cultivars to the disease. A field survey was made in six predominantly sorghum growing woredas/districts from three zones of northeast Ethiopia in 2001 main crop season. Disease assessment was made in a total of 102 farmers' fields, drawn by random selection of a total of 17 peasant associations (PAs) and then 6 fields from each PA. According to the findings of the study, the disease was widely distributed in sorghum fields in northeast Ethiopia with different incidence and severity levels. The zonal mean incidence for North Wolio was 12%, South Wollo 5%, and Oromiya 6%. The highest zonal mean severity was in North Wollo (13%). The disease occurred on all the cultivars grown by farmers in the three zones with varying incidence and severity levels. The improved variety 76T#23 (27%) and the local cultivar Humera (21%) were severely affected. Whereas, the local cultivar Degalit had the lowest incidence (5%) and severity (4%). The improved cultivars were more susceptible. In the cultivar reaction study, 38 sorghum genotypes were evaluated for resistance to the disease under artificial inoculation condition in the field. According to the findings, 4 of the genotypes were highly resistant and 3 resistant, while the other accessions were moderately resistant to susceptible. In conclusion, covered kernel smut was highly distributed and severe in northeast Ethiopia. On the other hand, there were some highly resistant local cultivars that were highly resistant, resistant or moderately resistant, indicating the good opportunity in local cultivars as sources of resistance that could be used in developing improved sorghum varieties.