The identity of Rps alleles and loci conferring resistance to phytoph-thora root rot can ordinarily be determined by means of a hypocotyl screening procedure. However, if more than one Rps allele pair is included in a line, allele identification by this procedure can be very difficult. Several soybean/phytophthora breeding programs are including two or three Rps allele pairs in single lines, in order to provide resistance to all of the races of Phytophthora megasperma f. sp. glycinea (Pmg) in their area (Athow, pers. comm.).