Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: October 10, 2004
Publication Date: December 10, 2004
Citation: Hartman, G.L., Miles, M.R., Frederick, R.D. 2004. Soybean rust: historical significance and u.s. perspective. Meeting Proceedings; 2004. Technical Abstract: Soybean rust, caused by Phakopsora pachyrhizi, occurs in all major soybean-growing regions of the world except the North American mainland. Soybean rust is one of the most destructive foliar disease of soybean. Yield losses of over 50% can occur when environmental conditions are conducive for disease development and no fungicides are applied. Heavily infected plants defoliate and mature more rapidly than plants not infected with rust. P. pachyrhizi has a broad host range and can infect many other legumes including some native to Australia. A number of physiological races of the fungus have been reported on these native legumes from Australia and on soybean. Four single genes for rust resistance were previously identified in four different soybean plant introductions. These sources of resistance also have been reported to be susceptible in some field locations and when challenged with certain isolates of P. pachyrhizi. Partial resistance, expressed as reduced pustule number and increased latent period, has also been reported, but has not been widely used in breeding programs. Yield stability, defined as the percentage of yield compared to fungicide control plots, has also been used in the past. Although soybean rust has not been found in the continental U.S., a proactive project to evaluate the USDA soybean germplasm collection for rust resistance was initiated in 2002 at the Fort Detrick BL-3 containment facility and at six international locations. Part of this project is to discover soybean lines with yield stability in the presence of rust, to find additional single genes for resistance, and define and utilize partial resistance. In addition to research on the host, there is also research on fungicide efficacy and application methods. Along with this, research is being developed on the epidemiology and its potential movement into the U.S. Lastly, there is a great deal of activity on educating growers, and scientists from industry and universities about soybean rust diagnosis and management of rust with the use of fungicides.