Anthracnose disease response in the Burundi sorghum germplasm collection

Abstract

The United States National Plant Germplasm System maintains 151 sorghum accessions from Burundi of which 148 accessions were evaluated for resistance to Colletotrichum sublineolum at the Tropical Agriculture Research Station in Isabela, Puerto Rico in replicated evaluations during the 2007 and 2008 growing seasons. For the 2007 experiment, 120 accessions showed a resistant response with 89 of these accessions rated as resistant in 2008. The resistant accessions showed reddening of inoculated leaves with no acervuli development, whereas accessions rated as susceptible showed acervuli development on inoculated leaves. Mean infection severity based on the percentage of infected leaf area for the susceptible accessions was 2% in 2007 and 2.5% for the 2008 experiment. Only four accessions showed an infection severity more than 10% and eight accessions showed a susceptible response across replications and growing seasons. Results of this study indicate that sorghum germplasm from Burundi is an important source of anthracnose resistance for sorghum improvement and that germplasm from regions of high annual rainfall is frequently associated with anthracnose resistance.