Submitted to: Canadian Journal of Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/21/2004
Publication Date: 1/11/2005
Citation: Bradley, C.A., Hartman, G.L., Mueller, D.S., Hoffman, D.D., Nickell, C.D., Pederson, W.L. 2005. Genetic analysis of partial resistance to rhizoctonia solani in the soybean cultivar 'savoy'. Canadian Journal of Plant Pathology. 27:137-142 Interpretive Summary: Rhizoctonia root rot, caused by the fungus Rhizoctonia solani, is a common disease of soybean in the north central United States and causes pre- and postemergence damping off in addition to rotting of the hypocotyl and roots. A previous study, in which several soybean cultivars were evaluated for resistance to R. solani, reported that the cultivar Savoy had partial resistance, while the cultivar Jack was susceptible. The objectives of this study were to determine the inheritance of this partial resistance. A population from a cross between the soybean cultivar Savoy and Jack was evaluated in the greenhouse. Reaction to R. solani in segregating generations indicated that resistance was inherited as a quantitative trait. This is the first report of genetic analysis of resistance to R. solani in a soybean cultivar, and provides information that may allow soybean breeders to select lines with partial resistance to R. solani more efficiently.
Technical Abstract: Rhizoctonia root rot, caused by Rhizoctonia solani Kühn, is a soilborne disease that can cause yield loss in soybean (Glycine max L. (Merr.)). The soybean cultivar 'Savoy' has partial resistance to R. solani. 'Savoy' was crossed to 'Jack', a cultivar that is susceptible to R. solani. Progeny from this cross was evaluated in the greenhouse for reaction to R. solani. Reaction to R. solani in segregating F2 and F3 generations indicate that resistance behaves as a quantitative trait. Heritability estimates indicate that selection for resistance to R. solani in soybean based on F2:3 family means would be more efficient than selecting on a single F2 plant basis.