Location: Corn, Soybean and Wheat Quality ResearchTitle: Quantitative Trait Loci for Partial Resistance to Phytophthora Sojaei in Soybean [Glycine Max (L.) Merr.]) Author
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/30/2010
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Phytophthora root and stem rot of soybean, caused by the oomycete, Phytophthora sojae, is one of the most destructive diseases to limit soybean production in the US. Although fourteen resistance genes (Rps) to P. sojae have been identified, adaptation of by the pathogen has made many of these ineffective. In addition to single-gene resistance, partial resistance or quantitative resistance to P. sojae is present in soybean. Such quantitative resistance provides effective long term defense against multiple isolates. The purpose of this study was to identify QTLs conferring partial resistance against P. sojae from new genetic sources, PI 398841 and PI 427861. Two F7 recombinant inbred line (RIL) populations, ‘OX20-8’ x ‘PI398841’ and ‘OX20-8’ x ‘PI407861’, with 350 and 165 individuals, respectively were used to map the QTL. The level of partial resistance was evaluated on 10 seven-day-old seedlings of RILs which were inoculated on the root approximately 20 mm below the stem/root interface with the P. sojae isolate C2S1 and OH25, respectively. Lesion size was measured 7 dai. The Illumina® Golden Gate 1536-plex SNP analysis was performed at the USDA-ARS Soybean Genomics and Improvement Laboratory in Beltsville, MD to detect polymorphism between parents. More than 500 SNPs were polymorphic between each pair of parents. Over 200 SNP markers were mapped in each population with 94 RIL lines using the Illumina® Bead Express assay. The QTL identified in these populations as well as their importance in soybean germplasm development will be presented.