1a. Objectives (from AD-416)
The discovery of genes or quantitative trait loci (QTL) that control yield per se in elite soybean germplasm.
1b. Approach (from AD-416)
The high yield reference genotype, IA3023, was crossed to 25 diverse accessions to create 25 populations with 200 recombinant inbred lines (RILs) each. Thus, each population shares the reference genotype as one of the parents. The 5000 RILs will be phenotyped by collaborators and genotyped with SNPs as per a typical QTL population analysis. The 25 diverse accessions will be extensively genotyped or sequenced which allows for high marker density which can be extrapolated to all the RILs in the 25 populations, thus greatly increasing the power to detect and fine map QTL. Using this approach, essentially all SNPs present in all 5000 RILs can be determined and the most common QTL among the 25 diverse lines can be discovered.
3. Progress Report
Funds are provided by the United Soybean Board, as part of Project #9241 entitled “Nested Association Mapping to Identify Yield QTL in Diverse High Yielding Elite Soybean Lines”. This project is being undertaken for the purpose of identifying genetic factors that positively impact soybean yield. Soybean inbred progeny are being developed from matings of the high yielding soybean cultivar (IA3023) with a broad spectrum of soybean lines from soybean breeders in Arkansas, Illinois, Indiana, Ohio, Tennessee, Missouri, and Nebraska. In the fall of 2009, seeds of individual F2 plants from 50 matings grown in Lincoln, NE and Urbana, IL were harvested. F3 seeds were subsequently planted in Puerto Rico as the first of two single–seed-descent generation advances. In the spring of 2010, F5 seeds of the 50 matings were harvested in Puerto Rico and subsequently planted in the field at Lincoln, NE and Urbana, IL with the objective of selecting F5 plants with maturity similar to IA3023. A leaflet was collected from each F5 plant for the purpose of DNA isolation. Progress is monitored via quarterly written reports and by frequent phone conferences with the collaborators at the University of Illinois and the University of Nebraska and via e-mail correspondence concerning the progress of the project.