Submitted to: American Journal of Agricultural and Biological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/13/2009
Publication Date: 8/31/2010
Citation: Erpelding, J.E. 2010. Field assessment of anthracnose disease response for the sorghum germplasm collection from the Mopti region of Mali. American Journal of Agricultural and Biological Science 5(3):363-369. Interpretive Summary: Anthracnose is a fungal disease that can greatly reduce sorghum grain production. The disease typically appears as lesions on infected leaves and can rapidly spread to all leaves, which may result in plant death. The disease can be successfully controlled using resistant cultivars. However, the anthracnose pathogen can rapidly change resulting in a loss of resistance; thus, new sources of resistance are needed for sorghum improvement. The USDA, ARS National Plant Germplasm System maintains an extensive collection of sorghum germplasm and evaluation of this collection is being conducted to identify sources of anthracnose resistance. Sorghum germplasm collected from the Mopti region of Mali was evaluated at the USDA, ARS Tropical Agriculture Research Station in Isabela, Puerto Rico. From the 97 sorghum germplasm lines evaluated, 45 lines showed a resistant response when inoculated with the anthracnose pathogen. Sorghum germplasm lines from specific districts within the Mopti region were more frequently associated with disease resistance. Weather conditions in these districts could be more favorable for anthracnose disease development and farmers in these regions would most likely select anthracnose resistant germplasm lines as a source of seed for planting. Additionally, sorghum germplasm can be classified into different races based on plant characteristics and the germplasm from the Mopti region shows genetic diversity that may also suggest genetic diversity for anthracnose resistance. Sorghum lines classified as race guinea from the Mopti region were also more frequently associated with anthracnose resistance as compared to sorghum lines classified as race durra or race durra-bicolor. This study resulted in the identification of new sources of anthracnose resistance and information from this study can be used to aid in the selection of germplasm from the sorghum collection to enhance the further identification of anthracnose resistant sources.
Technical Abstract: Sorghum anthracnose (Colletotrichum sublineolum) is a highly variable pathogen and new sources of host plant resistance are required for the development of resistant sorghum varieties. Germplasm collections are an important source of host plant resistance and screening germplasm will be essential to identify new sources of resistance. Approach: The sorghum (Sorghum bicolor) collection from the Mopti region of Mali was inoculated with Colletotrichum sublineolum and evaluated for foliar anthracnose disease response in Isabela, Puerto Rico during the 2004 and 2005 growing seasons using a partially balanced lattice design with three replications. Results: A resistant response was observed for 45 of the 97 accessions in the collection and mean infection severity for the 52 susceptible accessions was 27.6%. An association was observed between resistance and the administrative district where the germplasm was collected. More than 50% of the accessions from the Bandiagara and Bankass districts showed a resistant response. The lowest frequency of resistant germplasm was observed for the Mopti district with 25% of the accessions showing a resistant response. The susceptible accessions from the Mopti district, however, showed the lowest mean infection severity. Approximately 44% of the accessions from the Douentza district showed a resistant response with the susceptible accessions showing the highest mean infection severity. These results suggest an association between annual rainfall and anthracnose resistance, with sorghum accessions from drier regions showing greater susceptibility. Anthracnose resistance also showed an association with sorghum race classification and race guinea accessions were more frequently resistant as compared to accessions classified as race durra or durra-bicolor. Conclusions: The results indicate that anthracnose resistant sorghum germplasm is frequent in the Mopti region of Mali, and that ecogeographic origin and sorghum characterization information can be used to aid in germplasm selection or germplasm acquisition to identify anthracnose resistant sources.