Degree Type


Date of Award


Degree Name

Master of Science




Plant Breeding

First Advisor

Asheesh Singh


Soybean [Glycine max (L.) Merr.] is an economical source of protein and oil for livestock and human consumption. Seed protein and oil are quantitatively inherited traits and commonly have a genetic by environment interaction. Genetic improvement of soybean has been negatively associated with seed protein due to an inherent inverse relationship, and positively associated with seed oil, making it difficult for breeders to improve seed yield, protein and oil simultaneously. Diverse soybean accessions are a useful source of genetic diversity and considered important to bring in novel protein and oil quantitative trait loci (QTL). The objective of this study was to identify protein and oil QTL in a diverse bi-parental recombinant inbred line (RIL) mapping population consisting of 118 F6- derived lines. These RILs along with parents and checks were grown over two years across two locations (IA and IL) in replicated tests, and one IL location in an un-replicated test. Protein and oil (%) were determined using near-infrared spectroscopy (NIR). The mapping population was genotyped using the BARCSoySNP6K BeadChip array and after quality control 843 SNP markers were used in QTL mapping. QTL mapping was done in IciMapping software. Significant differences were observed between RIL genotypes for oil and protein at each environment, and RILs with oil and protein content greater than the high protein and oil parents. QTL in linkage with oil and protein composition were identified. As expected, several QTL were only identified at individual locations due to the quantitative nature of the trait. However some stable QTL were identified across more than two environments. The QTL in this experiment were then co-localized with previous reported QTL for protein and oil to validate or propose new QTL.


Copyright Owner

Kyle Parmley



File Format


File Size

87 pages

Included in

Agriculture Commons