Soybean cyst (SCN), root-knot (RKN), and reniform (RN) nematodes are the most yield limiting soybean pests in the southern US. Varieties are needed with resistance to all three species. Several SCN resistant plant introductions (PIs) have resistance to all three nematodes. Other sources with novel resistance genes/quantitative trait loci (QTL) can be discovered to collectively breed for resistance. The goals of this project are to evaluate SCN resistant and other sources with additional resistance to root-knot and reniform nematodes to discover unique genes for resistance to all three nematode species and to incorporate these genes into productive cultivars/germplasm.

Achieving the objectives:
• Screened over 600 soybean PIs for resistance to six SCN HG types. Identified 44 PIs, including unreported genotypes, showing high resistance to single- or multiple-SCN HG types.
• Completed phenotyping the 44 PIs for resistance to RKN and RN. Dual resistances of SNC and RKN was found for PIs 4004198B, P417091, 438489B, 468915, 494182, 507354, 507471, 548349, and 567516C. Seven of these lines PIs 404198B, 417091, 438489B, 468915, 507354, 507471, and 567516C have resistance to RN, as well, making them resistant to all 3 nematodes.
• Four mapping populations (Magellan x 438489B, Magellan x PI437690, Magellan x PI404198B) are being utilized for QTL mapping of multiple nematode resistances. Four QTL were identified in the 438489B populations- on Chromosomes 18, 8, 11, and 10.
• The genome wide association study (GWAS), using the 50,000 SNPs dataset developed by Drs. Cregan and Hyten, was completed using over 500 PIs from MG III-V evaluated for SCN HG type 0. In this study, six new loci were identified.
• Marker-assisted backcrossing (MABC) to develop near-isogenic lines (NILs) was progressed. Several BC4F2 crosses were made to develop NILS to use for identifying novel QTL regions on chromosomes 10 and 18.
• Fine-mapping of novel QTL on chromosome 10 with RILS of Magellan
• Fine-mapping of novel QTL O on Chr. 10 using 315 recombinant inbred lines (RIL) of the Magellan x PI 567516C population was completed. SSR markers associated with the QTL were developed, as were six additional SSR markers to be used for fine-mapping. To date the regions has been narrowed down 300 kb.
• Developed several productive lines with resistance to multiple nematode species. Twenty six advance breeding lines are being tested in yield trial in Missouri. All of the lines to PI437654 resistance. Two soybean varieties, S11-20356 and S11-20124, both with moderate resistance to SCN races 1, 2, 3, 5, and 14, RKN and RN were released in 2014. Both releases are also tolerant to salt and have frogeye leaf spot resistance.
• Other lines are being developed to add unique the SCN resistant alleles from PI 438489B and PI 567516c to elite lines with resistance to multiple nematode species in conventional and Roundup Ready backgrounds.

Not achieving objectives:
• None at this time.