Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/27/1998
Publication Date: N/A
Technical Abstract: Phytophthora rot, caused by Phytophthora sojae, is a very destructive disease of soybean. Races of P. sojae have been identified in Indiana, Iowa, Ohio, and other states that fail to activate the commonly used race specific resistance genes in soybean, resulting in a susceptible reaction by the host. If these races are prevalent in Illinois, soybean breeders will need to incorporate other sources of resistance to this pathogen into cultivars in their breeding programs. The objectives of this study were to isolate and identify races of P. sojae in the state of Illinois. Isolates obtained from 192 soil samples collected from throughout Illinois in 1997 were identified to race by inoculating a set of Williams isolines. Preliminary results indicate that many isolates are virulent on Rps 1 d and there appears to be some isolates with virulence combinations not previously reported. Results of this race survey will be presented and the implications for future cultivar development will be discussed.