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.
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”. During the winter of 2008-2009 a number of F1 plants from 50 crosses of elite and exotic soybean lines, each from crosses with the elite variety IA3023 were grown in the greenhouse at both the University of Illinois and the University of Nebraska, Lincoln. These 50 crosses with the common parent IA3023 were selected from a total of 120 crosses with IA3023 based upon an analysis of the elite and exotic parents with 1364 SNP DNA markers. This analysis was conducted in order to assure that a broad spectrum of genetic diversity was represented among the crosses that are used for the development of experimental lines to be used for the identification of genetic factors that positively impact soybean yield. The selected crosses were made by soybean breeders in a number of states including Arkansas, Illinois, Indiana, Ohio, Tennessee, Missouri, and Nebraska. 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.