Minnesota: Screened 280 ancestral lines for resistance or partial resistance to P. sojae in duplicate runs of rice inoculum assay and F. graminearum in duplicate runs of rice inoculum and rolled towel assays.
Association mapping of phenotypic with genotypic data detected no significant marker trait associations for partial resistance to P. sojae. Population size and/or marker density combined with environmental error in measurement of traits possessed insufficient power to detect significant marker-trait associations. As alternative to association mapping, six crosses were made between diverse sources, resistant and susceptible lines, for use in biparental mapping of resistance to P. sojae. Grow out of seed from crosses will be conducted in South American location to make seed available for 2016 growing season.
In phenotyping for resistance to F. graminearum measures of resistance included reduced root necrosis score and maintenance of relative root weight and relative root length when inoculated plants are compared to uninoculated. Association mapping detected a significant marker associated with reduced root necrosis (1 marker on chromosome 8) and multiple markers (10 markers on multiple chromosomes) for maintenance of relative root dry weight and root length.

Purdue: Narrowed location of RpsUN1 to 81kb from original 1,300 kb and RpsUN2 to 64kb from original 430kb. Pinpointed the candidate gene for RpsUN2. Begun haplotype analysis by comparing this region between PI 567139B and other genotyped soybean accessions to deduce RpsUN1 and RpsUN2 region-unique SNPs for use as molecular markers. RpsUN1 and RpsUN2 are being introgressed into elite breeding lines.

During this project year tests of multiple methods of inoculation with F. graminearum were conducted to validate the methodology, effectiveness, and consistency of the method used to conduct screening for resistance to seed, seedling, and root rot caused by F. graminearum. Based on these tests, the rolled towel assay and rice inoculum method were selected as the most reliable screening methods for assessing root rot and root development.
Utilizing these methods, rolled towel and rice inoculum assay, we completed phenotyping and association mapping of results obtained from multiple phenotyping assays of 280 ancestral lines for resistance or partial resistance to P. sojae and F. graminearum.
Association mapping performed on results obtained in P. sojae and F. graminearum phenotyping indicating the location of markers for partial resistance to F. graminearum. In 280 ancestral lines two categories of marker were identified that indicated resistance to F. graminearum, one marker located on chromosome 8 indicating resistance to root necrosis and 10 markers distributed on multiple chromosomes associated with resistance to loss of root mass. These markers may also be good targets for genomic selection for root rot resistance. Association mapping of phenotypic data for P. sojae partial resistance did not detect significant marker- trait associations for resistance to P. sojae although phenotyping indicated that 280 lines differed widely in response to P. sojae inoculation. To examine this phenomenon more closely we have elected to examine the results of biparental crosses between cultivars exhibiting a wide divergence of resistance to P. sojae inoculation. For this reason we completed six crosses of lines with divergent resistance characteristics, resistant and susceptible, for use in biparental mapping of resistance and partial resistance to P. sojae.
First run consisting of one rep of evaluation of 280 lines for resistance or partial resistance to P. ultimum is underway.
Pinpointed location of RpsUN1 and RpsUN2, identified RpsUN2 candidate gene, and began haplotype analysis to identify SNP markers associated with RpsUN1 and RpsUN2. Introgressed RpsUN1 and RpsUN2 into prebreeding lines and elite breeding lines.