1a.Objectives (from AD-416)
Develop SNP markers for soybean aphid resistance genes for marker assisted breeding for the Rag2 gene.
1b.Approach (from AD-416)
SNP (single nucleotide polymorphism) markers will be identified in the genomic regions of the aphid resistance genes using appropriate RIL mapping populations and near isogenic lines. The Solexa sequencing and Illumina and other genotyping platforms will be used for mapping the SNPs.
Rag2 is being fine mapped using 400 recombinant inbred lines (RIL) (F5:6) lines of the FG05 x PI 243540. We are mapping 7 Simple Sequence Repeat and 10 Single Nucleotide Polymorphism markers in a 3 cM region flanking the Rag2 gene on linkage group F. Phenotyping of the RILs was completed in May, and genotyping of the Rag2 region is currently underway. The Rag2 gene has now been mapped to an interval of less than 0.5 cM with SNP and SSR markers. A Light Cycler 480 assay will be developed and candidate genes will be identified for resistance to the aphids. We genotyped and phenotyped more than 2000 BC6F2 progeny and narrowed down the Rag2 gene in a window of <200 kb.
Recently, we have harvested more than 3000 BC4F2 seeds for finding more recombination closer to the Rag2 gene. More sequencing was done and two dozen primers designed for finding new polymorphic markers.
This research relates to objective 2A (Characterize and map aphid resistance genes in three soybean plant introductions) of the parent project.
The progress is monitored by monthly telephone conversation between the Co-PI and the authorized department officer's designated representative (ADODR) and quarterly written progress reports from Co-PI to ADODR. Also, face to face meetings of the Co-PI and ADODR at soybean breeder’s workshop once a year.