Characterization and mapping of RpsYu25, a novel resistance gene to Phytophthora sojae

P>Phytophthora root rot (PRR), caused by Phytophthora sojae Kaufm. and Gerd., is one of the most devastating diseases of soybean [Glycine max (L.) Merr.] worldwide. Growing PRR resistant cultivars is the major method of controlling this disease. However, populations of P. sojae, existing in many soybean-growing regions, cause disease on plants with the known Rps (Resistance to P. sojae) genes. Consequently, the need for new resistance loci is great. Chinese soybean lines 'Yudou 25' and 'Zheng 92116' showed different reaction types to P. sojae isolates as compared with those with known Rps genes, which suggests that these lines may carry novel resistance loci or alleles. To map the possible gene(s) for PRR resistance in 'Yudou 25' and 'Zheng 92116', two soybean populations, 'Yudou 25' x 'NG 6255' and 'Zheng 92116' x 'NH 5', were evaluated to determine their responses to P. sojae and genotypes of SSR markers. Results indicated that the resistance in these lines was conferred by the same single dominant gene, which is located on MLG N and temporarily designated RpsYu25.