Evaluation of Selected Genotypes of Soybean for Resistance to Phakopsora pachyrhizi

Soybean rust, caused by Phakopsora pachyrhizi Syd. & P. Syd., is one of the most destructive diseases of soybean [Glycine max (L.) Merr.] worldwide. To identify sources of resistance to domestic soybean rust fungus populations for plant breeding, our strategy has been to evaluate soybean lines that were previously identified as resistant to foreign isolates. In this study, two sets of plant introductions (PI) were evaluated using P. pachyrhizi urediniospores collected in Mississippi in 2006. The first set of PIs contained 10 lines previously identified as resistant in Paraguay, four PIs with known single genes for resistance to P. pachyrhizi, and Freedom and Williams 82 as susceptible checks. The second set included 17 lines that were selected based on information from Germplasm Resources Information Network (GRIN) and susceptible Williams 82. PI567102B was one of the most resistant lines to a Mississippi bulk isolate of P. pachyrhizi with the lowest severity rating, no sporulation, and red-brown lesion type.

Accepted for publication 25 April 2009. Published 15 June 2009.