Phytophthora stem and root rot (PRR) can result in severe yield losses, especially during wet growing seasons. The most cost effective way of managing PRR is through host resistance that incorporates major gene resistance (Rps) and partial resistance (multigenic). The proposed research will lead to the development of elite soybean lines with major single gene resistance to P. sojae as well as high partial resistance, thus improving the currently available disease management options for Phytophthora root rot. The lines introgressed with RpsN will provide additional protection for yields there by increasing the profitability for the farmers.

Summary of accomplishments:
1. Screening of the two RIL populations with P. sojae isolate R17 (1b,1d,3a,3b,3c,5,6) and combined R17 and Val12-11 (1a,1b,1c,1d,1k,2,4,7) isolates resulted in 2 genes and a single gene segregation, respectively.
2. Populations were screened with twelve polymorphic SSR markers identified in the parental lines and 3 were successfully mapped in one of the RIL populations.
3. Genetic maps were regenerated and the mapping was conducted using ICIMapping software.
4. F2 seeds of the AX20925 population are being screened to determine the gene action.
5. DNA pools of the resistant and susceptible RIL are currently being sequenced.

1. Generate molecular markers linked to RpsN.
2. Backcross RpsN into elite soybean germplasm lines.
3. Identify candidate RpsN genes.

1. Identification of useful molecular markers for marker assisted selection (MAS) for the novel RpsN gene –near completion.
2. Isolation of the candidate RpsN genes – expected to be accomplished in year 3 (FY2014- FY2015).
3. Transgenic lines carrying candidate RpsN genes will be developed – expected in the 3 year (FY 2014- FY 2015).
4. Progenies of the transgenic soybean lines will be analyzed to identify RpsN – expected in the 3rd year (FY2014-FY 2015).
5. Germplasm lines carrying the novel Rps gene which can be used to develop high yielding, P. sojae resistant experimental lines.
6. Data will be shared directly with soybean growers at field days and grower meetings organized and conducted by State University Extension and by the agribusiness industry.
7. Data will be shared with peers at scientific meeting.

Update:

Update:
See attached final report

View uploaded report

Manuscripts in progress
Matthiesen, R., Abeysekara, N., Maroof, S. and Robertson A.E. XXXX. Combining isolates to screen for novel sources of resistance to Phytophthora sojae in soybean. Plant Disease
Abeysekara, N., Bhattacharrya, M., Cianzio, S., Dorrance, A.E. and Robertson, A.E. XXXX. Identification of novel sources of resistance (Rps/QTL) in soybean with an inoculum mixture of three Phytophthora sojae isolates that vary in pathotype. Crop Science

1. Improved management of Phytophthora root rot in Iowa and throughout the North central region
2. Improved stand establishment and reduced yield losses
3. Increased farmer profitability