School of Agricultural, Earth and Environmental Sciences

Dr Girma Mengistu Digafe.

Tackling Devastating Crop Disease to Improve Ethiopia’s Sorghum Production

Dr Girma Mengistu Digafe was awarded his PhD in Plant Breeding at UKZN’s Spring Graduation. His study investigated the pre-breeding of sorghum for agronomic traits and anthracnose disease resistance in western Ethiopia.

Sorghum is Ethiopia’s third most important crop after tef and maize, and is the fifth most important cereal crop globally. Its production in western Ethiopia is threatened by several biotic and abiotic factors, including diseases, insect pests, and weeds. Sorghum anthracnose is the most devastating disease in the region, causing yield losses of up to 70% on susceptible varieties.

Given that use of anthracnose resistant sorghum genotypes is regarded as the most economic and environmentally friendly control option, Digafe set out to breed new sorghum populations with anthracnoseresistance and better yield gains.

‘In this region, there was no breeding effort aimed at developing sorghum cultivars with anthracnose resistance,’ said Digafe. ‘Some introduced cultivars and cultivars developed by the national sorghum programme were released in the past 10 years; however, farmers did not adopt them due to their inherent short plant height, low biomass yield, early maturity and susceptibility to bird and disease attacks.’

He began by assessing farmers’ perceptions and preferences, and the constraints affecting sorghum production and productivity in western Ethiopia, moving on to determine the genetic variability present among the country’s sorghum landraces. The lines were genotyped using SNP markers, and found to be genetically unique and distantly related, useful for genetic gain for yield and yield components through heterosis breeding.

Digafe developed new breeding populations with moderate resistance to anthracnose and with the traits preferred by farmers, that will be used in sorghum breeding and direct production to improve sorghum productivity.

He said that the skills he acquired during his PhD will assist him to develop improved cereal crops, focusing on sorghum, and ultimately contribute to improved production and productivity and sustainable production of the crop by smallholder farmers in Ethiopia.

‘My study helped me to learn advanced crop breeding methods and the development of improved crop varieties that integrate farmers’ preferred traits, otherwise farmers become reluctant to grow the improved varieties,’ said Digafe.

Having studied at Haroyama University in Ethiopia for his prior degrees, Digafe chose to pursue his PhD at UKZN because of its strength in plant breeding with a focus on practical application and problem-solving oriented research that considers farmers’ needs.

Digafe published three scientific papers from his research in high impact journals, with further papers under review. South Africa’s National Research Foundation (NRF) and the Agricultural Growth Programme of the Oromia Agricultural Research Institute (OARI) in Ethiopia, where Digafe works as a senior researcher in the Crop Directorate, funded his research.

Digafe thanked his supervisor, Professor Hussein Shimelis, his co-supervisor Professor Mark Laing, and his in-country supervisor, Dr Dagnachew Lule, for their support, advice and encouragement. He acknowledged the NRF for funding received and the Biosciences Eastern and Central Africa Integrated Genotyping Service and Support platform for assisting with genotyping of the sorghum accessions. He also thanked OARI for enabling him to pursue his PhD studies, and UKZN for providing an excellent academic environment.

Words: Christine Cuénod

Photograph: Supplied