Response of Sorghum Accessions from Three African Countries to Anthracnose, Grain Mould and Rust

Louis K. Prom, Hugo E. Cuevas, Ezekiel Ahn, Thomas Isakeit and Clint Magill

Background and Objective: Sorghum is one of the most indispensable crops, especially in the drier tropics where many millions of people rely on it for their daily calories intake. However, the crop is hampered by several biotic stresses, causing annual economic losses estimated at hundreds of millions of dollars. The study aimed to evaluate diverse sorghum germplasm for resistance against pathogens causing anthracnose, grain mould and rust. Materials and Methods: A total of 179 accessions from Ethiopia, Gambia and Senegal were evaluated for resistance to anthracnose, grain mould and rust during the 2017 and 2018 growing seasons. Seeds were planted in a randomized complete block design and each accession was replicated 3 times at the USDA Research Station, Isabela, Puerto Rico. Disease assessment and germination rate were based on published procedures. Results: Out of the 179 accessions evaluated, 138 were resistant to anthracnose. Among these anthracnose resistant accessions, 41 accessions, including PI276832, PI534001, PI533903 and PI665159 also were resistant to Puccinia purpurea, which causes rust. Three accessions PI514411, PI514318 and PI514538 out of the 138 anthracnose resistant accessions were also resistant to grain mould. Two accessions PI514318 and PI514538 from Senegal were resistant to all 3 diseases. Among the anthracnose resistant accessions, 20 recorded a 90% or above germination rate. Germination rate was correlated with the sorghum responses to the 3 diseases, a positive correlation was found between germination rate and severity to rust, while negative correlations were detected between germination rate and severities to anthracnose and grain mould. Conclusion: The work is significant because it has identified 2 accessions that are resistant to anthracnose, grain mould and rust. The identified accessions may be useful in breeding programs to introgress the resistance genes they possess into elite or parental lines beyond Puerto Rico.

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