Evaluation of Ethiopian sorghum accessions for resistance against Colletotrichum sublineolum

Field experiments were conducted in the 2007 and 2008 cropping seasons in Wolayta, southern Ethiopia, to assess the reaction of 56 Ethiopian sorghum accessions and two susceptible checks (AL70 and BTx623) to anthracnose from naturally occurring inoculum. Final anthracnose severity (FAS), relative area under the disease progress curve (rAUDPC, where a commonly used susceptible cultivar, AL70, was set to 1), and anthracnose progress rate were used as evaluation parameters. All the evaluation parameters revealed significant variation among the tested accessions. In 2007, anthracnose severity varied between 6.6 and 77.7%, and in 2008 it ranged from 9.7% to 76%. The Ethiopian sorghum accessions had rAUDPC ranging from 0.13 to 0.88 in 2007 and from 0.18 to 1.35 in 2008. Anthracnose progress rate varied between 0.02 and 0.06 and from 0.01 to 0.05 units per day in 2007 and 2008, respectively. Results from the three parameters were highly correlated (0.18–0.87), suggesting FAS would be a suitable selection parameter for germplasm screening. Fifteen accessions in 2007 and 18 in 2008 were rated as resistant, with six accessions rated as resistant in both years, suggesting germplasm from Ethiopia would be useful for breeding resistance to anthracnose.