Covered kernel smut, caused by Sporisorium sorghi is a major threat to sorghum (S. bicolor L. (Moench) production globally resulting in yield losses as high as 75% on susceptible sorghum in Zimbabwe. Twelve sorghum genotypes were screened to determine the incidence and severity of covered kernel smut under field conditions during the 2014/15 growing season. In addition, the trial was done under artificial field inoculation to observe the reaction of the sorghum genotypes, where two artificial inoculation techniques which include seed dressing with dry teliospores and stem injection were used. The experiment was set up using randomised complete block design with three replicates in the field. The disease incidence was highly distributed and it varied significantly (p < 0.001) between the sorghum genotypes. A range of 0 to 40% incidence of the disease was recorded with varieties SV-1 and ICSR 93034 having 0 and 40%, respectively. Similarly, severity also followed the same trend as that of incidence with SV-1 having a mean score of 1, while ICSR 93034 had 4.66. NL 2015 produced the highest mean grain yield of 1.7467 tonnes/ha, while NL 2014 had the lowest mean grain yield of 0.1903 tonnes/ha. Grain yield loss was 24.3%. The screened sorghum genotypes namely SV-1, NL 2015 and ICSR 93024 exhibited high levels of resistance to covered kernel smut pathogen.

Keywords: Covered kernel smut, sorghum, genotypes, disease and yield.