Field Evaluation of Anthracnose Resistance for Sorghum Germplasm from the Sikasso Region of Mali

Abstract

Sorghum anthracnose is a highly variable pathogen and occurs in most sorghum producing regions worldwide. The disease can be managed using resistant varieties, but additional sources of resistance are needed for sorghum improvement. Germplasm collections are an important resource for the identification of host plant resistance and the 132 sorghum landraces from the Sikasso region of Mali were inoculated with Colletotrichum sublineolum and evaluated for foliar anthracnose resistance in Isabela, Puerto Rico during the 2004 and 2005 growing seasons. A resistant response was observed for 109 accessions. For the 23 susceptible accessions, infection severity was low with a mean infected leaf area of 5.6%. Only one accession was rated as highly susceptible. Anthracnose resistant germplasm was more frequently associated with the southern administrative districts that experience higher annual rainfall. More than 80% of the accessions from the Bougouni and Sikasso districts showed a resistant response. The lowest mean infection severity, 1.5%, was observed for accessions from the Sikasso district. In comparison, 71% of the accessions from the drier, northern Koutiala district showed a resistant response, with a mean infection severity of 8.8% for the susceptible accessions from this district. Nearly all landraces from the Sikasso region were classified as race guinea and the guinea landraces that were further classified as margaritiferum were all rated as resistant. Results indicate that the Sikasso region of Mali could be an important source of anthracnose resistant germplasm and that ecogeographic origin and race classification could be used to select germplasm for additional disease evaluations.