Pathotype Diversity of Phytophthora sojae in Eleven States in the United States

• DOI: 10.1094/pdis-08-15-0879-re
• Publication Date: 2016-02-11T12:48:31Z
• Authors: A. E. Dorrance; J. Kurle; A. E. Robertson; C. A. Bradley; L. Giesler; K. Wise; V. C. Concibido
• Keywords: Phytophthora sojae

Pathotype diversity of Phytophthora sojae was assessed in 11 states the United States during 2012 and 2013. Isolates P. were recovered from 202 fields, either soil samples using a soybean seedling bioassay or by isolation symptomatic plants. Each isolate inoculated directly onto 12 differentials; no Rps gene 1a, 1b, 1c, 1k, 3a, 3b, 3c, 4, 6, 7, 8. There 213 unique virulence pathotypes identified among 873 isolates collected. None genes effective against all collected but Rps6 Rps8 majority northern regions sampled area. Virulence toward Rps1a, 1k ranged 36 to 100% each state, while less than 10%, respectively. Depending on effectiveness Rps3a totally susceptible more 40% isolates. complexity has increased populations States, emphasizing increasing importance stacked combination with high partial resistance as means limiting losses sojae.