Funding fro the Tennessee Soybean Promotion Board is an absolute necessity to supplement USDA-ARS funds to aggressively target SCN, Charcoal rot (CR) and, Frogeye leaf spot (FLS) resistance research. These funds from TNSPB will be valuable for continued hiring of a trained full-time research technician for ongoing disease screenings in the greenhouse. The proposed research is a mandate because soybeans are planted on more acres than any other row crops in Tennessee, with one million acres grown annually. Each year, soybeans rank in the top three for cash receipts for row crops. Statewide yields are typically range from 38-46 bu/acre. Yield losses due to SCN alone averages 10% per acre and combined losses due to SCN, CRR and FLS are in excess of 20% per are in Tennessee. These losses remained stable at current levels for SCN with the use of resistant varieties but, over time nematode populations will evolve and adapt to deployed resistance genes in these resistant varieties thus rendering them susceptible. This means, all the resistant varieties developed by the major seed industries will continue to be at risk for SCN resistance. More durable and broad resistance is needed for SCN populations and can be achieved with the use of diversified sources. Currently, soybean cultivars with combined resistance to SCN, CR, and FLS are not readily available. We have identified these unique sources of resistance and crossed with elite soybean lines. The progenies are being advanced in field for selection of desirable lines having resistance to all three diseases. This is a multi-year project. However, to reduce the amount of time needed to develop soybean lines pyramided with genes for resistance to SCN, CR and, FLS, we are using ‘genetic markers’ tagged to some of these diseases that are applied in combination with traditional breeding methods. Concurrently, we also use greenhouse screenings for these diseases for confirmation of resistance in the selected lines. We also developed improved nematode populations from field populations for greenhouse tests to produce uniform reaction on soybean selections for resistance.

1. Develop high yielding soybeans adapted to Tennessee with broad resistance to emerging soybean cyst nematode (SCN) populations and stacking with resistance genes for predominately yield limiting pathogens in TN.
2. Develop, modify and use existing biotechnology in breeding for rapid gains especially, using DNA markers tagged to resistance.

The ongoing research with renewed funding from TNSPB will reduce the risk of economic losses by these yield reducing pathogens especially SCN for Tennessee soybean producers and will benefit by having productive soybeans developed in collaboration with UT by USDA-ARS in Jackson, TN. Further, with renewed interest in high yielding conventional soybeans having resistance to multiple pathogens, growers can also be benefitted by their adoption in Tennessee.