Mining exotic germplasm for genetic improvement of protein quantity and quality in soybean (glycine max)

Authors: SOUZA, RENAN - University Of Georgia; BUCKLEY, BLAIR - Louisiana State University; Mian, Rouf; LI, ZENGLU - University Of Georgia

Submitted to: Plant Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2024
Publication Date: 3/6/2024
Citation: Souza, R., Buckley, B., Mian, R.M., Li, Z. 2024. Mining exotic germplasm for genetic improvement of protein quantity and quality in soybean (glycine max). Plant Breeding. https://doi.org/10.1111/pbr.13165.
DOI: https://doi.org/10.1111/pbr.13165

Interpretive Summary: Soybean is the second largest row crop in USA after corn. Soybean is the number one source of plant protein worldwide, however, its amino acid profile is not ideal because it has low concentrations of cysteine (Cys) and methionine (Met). A plant introduction from South Korea (PI 399000) was crossed cultivar ‘Woodruff’ to develop a recombinant inbred line (RIL) population for mapping quantitative trait loci (QTL) for seed composition. The population was grown in six environments and protein, oil, Cys, and Met concentrations were determined with near-infrared spectroscopy. RILs were genotyped with the SoySNP6K BeadChip and 1865 SNPs were used for QTL analysis. Entry mean-based heritability was 0.93, 0.92, and 0.82 for protein, oil and Cys + Met, respectively and a negative correlation between protein and Cys + Met was observed (-0.48). QTL analysis identified three loci on chromosomes (Chrs) 6, 15, and 17 in at least five environments for protein, six QTLs on Chrs 4, 6, 10, 14, 17, 19 in at least two environments for oil, three QTLs on Chrs 3, 6, and 10 for Cys and Met in at least two environments and two QTLs for seed size on Chrs 17 and 20 in all environments. Stacking of protein and Cys + Met QTLs in this population can increase both traits simultaneously and 13 breeding lines were identified with improved seed composition. The markers linked to the QTLs for high protein and elevated amino acid concentration and the germplasm developed in this research will be useful to the soybean community in the U.S. and beyond.

Technical Abstract: Soybean meal is the main protein source for animal feed, but its amino acid profile is not balanced, having low concentrations of cysteine (Cys) and methionine (Met). In this research, an exotic germplasm (PI 399000) was crossed with ‘Woodruff’ to develop a recombinant inbred line (RIL) population for mapping quantitative trait loci (QTL) for seed composition. The population was grown in six environments and protein, oil, Cys, and Met concentrations were determined with near-infrared spectroscopy. RILs were genotyped with the SoySNP6K BeadChip and 1865 SNPs were used for QTL analysis. Entry mean-based heritability was 0.93, 0.92, and 0.82 for protein, oil and Cys + Met, respectively and a negative correlation between protein and Cys + Met was observed (-0.48). QTL analysis identified three QTL on chromosomes (Chrs) 6, 15, and 17 in five environments for protein, six QTLs on Chrs 4, 6, 10, 14, 17, 19 in two environments for oil, three QTLs on Chrs 3, 6, and 10 for Cys and Met in two environments and two QTLs for seed size on Chrs 17 and 20 in all environments. Stacking of protein and Cys + Met QTLs in this population can increase both traits simultaneously and 13 breeding lines were identified with improved seed composition. The markers linked to the QTLs for high protein and elevated amino acid concentration can be used to develop soybean cultivars with improved soybean meal.