Evaluation of sorghum genotypes and influence of weather variables on anthracnose ( Colletotrichum sublineolum ) disease development under field conditions at Jimma, southwestern Ethiopia

The severity and temporal dynamics of sorghum anthracnose on six and nine sorghum genotypes were evaluated on field plots during 2014 and 2015 cropping years in Southwestern Ethiopia, respectively. Anthracnose severity was assessed as the proportion of leaf area affected by the disease. 12 consecutive time point anthracnose severity assessments and their mean severity, disease progress rate, AUDPC, grain yield and yield related components were used to evaluate the response of the genotypes. In the year 2014 and 2015, the mean anthracnose severity was varying from 65 to 79 PSI and 54–82 PSI among six and nine sorghum genotypes, respectively. AUDPC varied from 5063 to 6113%-day and 4171 to 6383%-day in the year 2014 and 2015, respectively. BRC-378 and BRC-245 genotypes consistently had the lowest disease levels and highest grain yields during the two experimental years. The disease pressure was reduced, whereas grain yield and 1000-seed weight of the genotypes were increased in 2015 cropping year. Anthracnose severity was strongly correlated with weather variables and showed strong negative associations with grain yield of all tested sorghum genotypes.