Update:
refer to final report

This is the final technical report for the 2nd year period (FY2017) of a 3-year project initiated in FY2016. The project was built on our previous discovery of four novel Rps genes (Rps11, RpsUN3, Rps1-das, and Rps2-das) conferring excellent resistance to a broad spectrum of Phytophthora sojae races and aims to incorporate these novel Rps genes into elite soybean cultivars for enhanced and long-lasting resistance.

Specific activities and objectives are:
1) Introgress the genomic regions carrying Rps11, Rps12 (or RpsUN3), Rps1-das, and Rps2-das into the elite cultivars, including two Purdue cultivars and two Illinois cultivars.
2) Develop Rps11, Rps12, Rps1-das, and Rps2-das isogenic lines using Williams as recurrent parental lines in backcrosses with the donor lines of these four genes.
3) Determine if Rps1-k, RpsUN1, and Rps1-das, and Rps2, RpsUN2, and Rps2-das in the two resistance gene clusters are different genes.
4) Pyramid more than one of the four novel genes and/or the two known genes into same elite cultivars. The proposed work in the FY2017 project is very similar to that from the FY2016 project, but the materials have been advanced for an additional generation in 2017 in the Agronomy farm.

The progresses of specific objectives are summarized below:

1) Introgress the genomic regions carrying Rps11, RpsUN3, Rps1-das, and Rps2-das into the elite cultivars, including two Purdue cultivars and two Illinois cultivars.

Progress: By the end of October 31,2018, the 3rd generation of backcrosses as the process of introgression of the four Rps genes into four elite soybean cultivars have been made successfully in the Purdue Agronomy farm. Molecular markers lined to these genes were used to examine seeds from the backcrosses for precise selection of progeny with each of the four genes.

2) Develop Rps11, RpsUN3, Rps1-das, and Rps2-das isogenic lines using Williams as recurrent parental lines in backcrosses with the donor lines of these four genes.

Progress: The 3rd generation of backcrosses of progeny lines with individual Rps genes to Williams for have been made in the Purdue Agronomy farm during this just ended soybean growing season, and molecular markers lined to these genes were used to examine seeds from the backcrosses for precise selection of progeny with each of the four genes, towards development of the four genes' isogenic lines in the Williams genetic background.

3) Determine if Rps1-k, RpsUN1, and Rps1-das, and Rps2, RpsUN2, and Rps2-das in the two resistance gene clusters are different genes.

Progress: F2 and/or F3 seeds derived from crossed between two of the Rps1-k, RpsUN1, and Rps1-das lines and between two of the Rps2, RpsUN2, and Rps2-das lines have been evaluated for resistance in greenhouse. However, because the genes in a same chromosomal region are closely linked, allelic test does not seem top be efficient. Alternatively, we are fine mapping Rps1-das and Rps2-das, and the results suggest that Rps2-das is a novel gene different from RpsUN2 and Rps2, and Rps1-das is most likely a novel allele at the Rps1 locus. Evaluation of these genes with a large set of P. sojae isolates collected from Indiana State also suggests these two genes are either novel genes or novel alleles.

4) Pyramid more than one of the four novel genes and the two known genes into same elite cultivars.
Progress: No progress has been directly made for this objective. Nevertheless, continuing introgression of one of the four Rps genes into single cultivars will facilitate the final pyramiding of different Rps genes into a same cultivar that was planned to be conducted in year 3.