Submitted to: Crop Protection Journal
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/13/2007
Publication Date: 12/1/2007
Citation: Prom, L.K., Cisse, N., Ndoye, O. 2007. Assessing the vulnerablitiy of selected sorghum lines from the United States of America to long smut (Sporisorium ehrenbergii Vanky) disease. Crop Protection. 26:1771-1776. Interpretive Summary: Long smut of sorghum is an important disease in Africa and Asia and in several other countries. In the United States, long smut is not present. As a result, there is little or no information on how the U.S. sorghum lines will react to the disease when they are exposed to it. In this study, selected U.S. commercial hybrids and sorghum cultivars were screened in areas in Senegal, West Africa where long smut is present. No infection was noted on hybrids 3552 and A571 in 2005 at both locations. Hybrids 730, 837, P84552, TR438, TR65G, and Wac660 have low levels of infection. Apart from the two cultivars B.9612 and R.9645 which may be resistant to long smut, all other promising sorghum U.S. cultivars and parental lines tested have different levels of infection. These results suggest that commercial sorghum hybrids/cultivars which have one or more of the parental lines in their backgrounds are likely to be infected with long smut when they are exposed to the disease. Since long smut cannot be controlled with chemical seed treatment, it is important that sources of resistance from U.S. sorghum lines be identified. In the future, if long smut is observed in the U.S., sound control methods could be put in place immediately to protect sorghum growers and the seed industry.
Technical Abstract: Long smut is a limiting factor in sorghum productivity in some countries and therefore, a threat to food security. To assess long smut (Sporisorium ehrenbergii Vanky) disease response, experiments were conducted with 51 sorghum accessions including 31 commercial hybrids and 20 cultivars from the United States in 2004 and 2005 at the Agronomic Research Stations in Bambey and Nioro, Senegal, West Africa. The highest disease incidence of 44.33% in 2004 and 16.47% in 2005 was observed in hybrid A425, and no infection was noted on hybrids 3552 and A571 in 2005 at both locations. Hybrids 730, 837, P84552, TR438, TR65G, and Wac660 exhibited low levels of infection. Among the cultivars and parental lines, SRN39 recorded the highest disease incidence of 48.0% followed by B.Tx623 with 45.8% where as B.9612 and R.9645 consistently recorded low levels of infection. The two cultivars B.9612 and R.9645 may possess genes for long smut resistance. All other promising sorghum cultivars and parental lines to be released/registered in the U.S. exhibited varied levels of susceptibility. In order to establish the sources of long smut resistance, it is of paramount importance to conduct additional screenings of aforesaid hybrids/lines in a wide spectrum of selections that would be carried out under varied environmental conditions.