Results on KPI’s met, 1, 2, 3, and 4.
• Analysis of the Soybean Germplasm Collection identified, PI 229343, with high sucrose (>8.0%) and low stachyose (2.44%), and PI 417015 with high sucrose (>8.0%).
• For low RFO’s, one new accession, FC 31721, was identified and confirmed to be low raffinose (0.55%) and relatively low stachyose (1.9%) levels.
• Two new accessions with high sucrose, PI 229343 and PI 417015, were crossed to develop recombinant inbred line mapping populations for genetic mapping.
• Six F2 populations were developed from crosses of these two PIs and other high yielding elite lines for genetic mapping and breeding purposes.
• A new source of low raffinose, FC 31721, was also crossed with other PI lines and with a null trypsin inhibitor (KTI) line, PI 524044, for further genetic study and breeding.
• Analysis showed that stachyose and raffinose content typically segregated for a phenotypic segregation ratio of 3:1 and was genetically controlled by the SS gene. This genetic Indel marker was subsequently utilized to detect lines with desired genotypes of RFO’s content in six new breeding populations.
• In combination with a newly developed a co-dominant Indel marker of the SS gene and existing SNP markers of the st/st gene, it can be demonstrated that soybean molecular breeding for low RFO’s can be effectively conducted to develop new germplasm or variety with desirable target levels of stachyose and raffinose content.
• As of June, 2014, a total of 30 new crosses were produced, generating several F2 populations. Of these, several populations are currently being advancing in the winter nursery in Costa Rica to develop inbred lines for breeding program.
• PI 524044 has low trypsin inhibitor and elite line KB07-15 has low raffinose and low stachyose. These accessions have been used to develop several breeding populations. F5 lines developed from these populations were genotyped using a newly developed Indel marker and existing SNP marker (st/st) to select desirable genotypes. Approximately 15 lines with desired genotypes from each population were selected and then transplanted into a greenhouse in an attempt to confirm sugar content. Results showed a perfect correlation between the phenotypic data and the marker data. Fourteen lines with low RFOs (stachyose + raffinose = 2.0-2.8%) were increased in the winter nursery in Costa Rica.