Assessing the vulnerability of selected sorghum lines from the United States of America to long smut (Sporisorium ehrenbergii Vánky) disease

Long smut is a limiting factor in sorghum productivity in some countries and therefore, a threat to food security. Long smut (Sporisorium ehrenbergii Vánky) disease response was assessed in experiments on 51 sorghum accessions including 31 commercial hybrids and 20 cultivars from the United States of America (USA) 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 in 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%, whereas B.9612 and R.9645 consistently recorded low levels of infection. These 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 USA 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.