Author
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SLAMINKO, TARA - University Of Illinois |
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Bowen, Charles |
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Hartman, Glen |
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 11/29/2009 Publication Date: 3/1/2010 Citation: Slaminko, T., Bowen, C.R., Hartman, G.L. 2010. Multi-Year Evaluation of Commercial Soybean Cultivars for Resistance to Phytophthora sojae. Plant Disease. 94:368-371. Interpretive Summary: Phytophthora sojae is a pathogen of soybean that causes damping off, root rot, and stem rot of soybean. The use of resistance has been one of the primary management tools used to control this disease. The Varietal Information Program for Soybeans at the University of Illinois evaluates soybean cultivars for resistance to a number of diseases including Phytophthora root rot. The objectives of this research were to evaluate Phytophthora root rot resistance among commercial or near-commercial cultivars from private and public soybean breeding programs, and to compare these results with the company-provided information on PRR resistance. Each year from 2004 to 2008 between 600 and 900 cultivars were evaluated for resistance. Single resistance genes were reported in 51% of the entries. This information is useful to soybean scientists in public institutes and private companies that develop soybean cultivars. Technical Abstract: Phytophthora sojae causes damping off, root rot, and stem rot of soybean, particularly in poorly drained soils. The use of resistance has been one of the primary management tools used to control this disease, with the most commonly used genes being Rps1c and Rps1k, followed by Rps1a. The Varietal Information Program for Soybeans (VIPS) at the University of Illinois evaluates soybean cultivars for resistance to a number of diseases including Phytophthora root rot (PRR). The objectives of this research were to evaluate PRR resistance among commercial or near-commercial cultivars from private and public soybean breeding programs, and to compare these results with the company-provided information on PRR resistance. Each year from 2004 to 2008 between 600 and 900 cultivars were evaluated for resistance to either race 17 or 26 of P. sojae using the hypocotyl inoculation method. P. sojae single resistance genes were reported in 1,808 or 51% of the entries. Of these, the most commonly deployed resistance genes were Rps1a (10%), Rps1c (50%), and Rps1k (40%). Used to a much lesser extent were Rps1b (0.2%), Rps3a (0.3%), and Rps7 (0.2%). For the duration of the 5-year testing period, almost half of the cultivars had no reported resistance genes, and only nine out of a total of 3,533 entries contained a combination of resistance genes. Agreement between company-reported genes and the VIPS trials was highest for Rps1c (90%) and Rps1k (83%), followed by Rps1a (70%). |