Plant architecture genes affect seed composition and seed weight in soybeans grown in the Midsouth USA

Authors: Bellaloui, Nacer; Smith, James; RAY, JEFFERY - Retired ARS Employee; Kumar, Neeraj; Feng, Chunda; ABDELRAHEEM, ABDELRAHEEM - Oak Ridge Institute For Science And Education (ORISE)

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/16/2026
Publication Date: 3/9/2026
Citation: Bellaloui, N., Smith, J.R., Ray, J.D., Kumar, N.N., Feng, C., Abdelraheem, A. 2026. Plant architecture genes affect seed composition and seed weight in soybeans grown in the Midsouth USA. Frontiers in Plant Science. 17:1-13. https://doi.org/10.3389/fpls.2026.1785158 .
DOI: https://doi.org/10.3389/fpls.2026.1785158

Interpretive Summary: The Early Soybean Production System (ESPS) in the Midsouth is characterized by high humidity, high heat, water deficient, and disease pressure. Therefore, optimizing soybean plant architecture adapted to the ESPS is essential for maximizing seed yield and seed composition (nutrition). The objective of this research was to investigate the effect of plant architecture (stem termination genes) on seed composition/nutrition (seed protein, oil, fatty acids, and sugars), and seed size (100-seed weight). We evaluated four developed breeding lines of maturity group (MG) five (V) that were adapted to the ESPS in the Midsouth. The four breeding genotypes are: indeterminate, tall determinate, semi-determinate, and determinate. Two cultivars were used as checks. A 3-year field experiment was conducted in 2022, 2023, and 2024 at Stoneville, MS. The results showed that the semi-determinate and Osage had higher seed protein content than the determinate (det), indeterminate (indet), and tall-determinate (tall-det) genotypes. Oil content in the semi-det was also higher than both checks, and comparable with the other genotypes. Oleic acid was higher in the semi-det and indet genotypes than in the det in 2022 and 2023. Raffinose content was higher in the tall-det and det isolines than in the semi-det isoline in 2022 and 2023, while stachyose was higher in the tall-det and indet isolines than in the semi-det type in 2023 and 2024. The 100-seed weight was highest in the semi-det, tall-det, and determinate in all three years. Across the three years, and among the all lines, semi-det had the highest protein, oleic acid, and 100-seed weight. To our knowledge, this is the first report comparing these four plant architecture types in a MG V genetic background in the ESPS in the Midsouth. This research demonstrated that the semi-det stem termination type contained the highest seed protein, acceptable levels of oil, and larger seed size than the other types, all potentially desirable traits for soybean producers and the seed industry. This research contributes to the USDA priority to increase profitability of farmers.

Technical Abstract: The Early Soybean Production System (ESPS) in the Midsouth is characterized by high humidity, high heat, water deficient, and disease pressure. Therefore, optimizing soybean plant architecture adapted to the ESPS is essential for maximizing seed yield and seed composition (nutrition). The objective of this research was to investigate the effect of plant architecture, i.e., stem termination genes on seed composition/nutrition (seed protein, oil, fatty acids, and sugars), and seed size (100-seed weight). We used a set of four near-isogenic stem termination lines from maturity group (MG) V that were adapted to the ESPS in the Midsouth. The four germplasm near-isogenic lines are USDA-ARS-GDS-880Dt1 (indeterminate), USDA-ARS-GDS-880dt1-t2 (tall determinate), and USDA-ARS-GDS-880Dt2 (semi-determinate), and determinate-dt1, with differing plant architectures derived from different stem termination genes. This set of near-isogenic lines was developed by a backcrossing, using DS-880 (PI 659348; dt1) as the recurrent parent. These isolines are F5-derived bulked lines, and each backcrossed line has approximately 97% genotype of the recurrent parent (DS-880). A 3-year field experiment was conducted in 2022, 2023, and 2024 at Stoneville, MS. DS49-142 (check1) was used as the MG V high protein check, and ‘Osage’ (check2) was used to represent MG V cultivars, and both are determinate. The results showed that the semi-determinate (semi-det), DS49-142, and Osage had higher seed protein content than the determinate (det), indeterminate (indet), and tall-determinate (tall-det) isolines in 2022, 2023, and 2024. Oil content in the semi-det was also higher than both checks, and comparable with the other genotypes. Oleic acid was higher in the semi-det and indet genotypes than in the det in 2022 and 2023. Raffinose content was higher in the tall-det and det isolines than in the semi-det isoline in 2022 and 2023, while stachyose was higher in the tall-det and indet isolines than in the semi-det type in 2023 and 2024. The 100-seed weight was highest in the semi-det, tall-det, and DS49-142 in all three years. Across the three years, and among the all lines, semi-det had the highest protein (38.95%), oleic acid (21.90%), and 100-seed weight (15.17 g). To our knowledge, this is the first report comparing these four plant architecture types in a MG V background in the ESPS in the Midsouth. This research demonstrated that the semi-det stem termination type contained the highest seed protein, acceptable levels of oil, and larger seed size than the other types, all potentially desirable traits for soybean producers and the seed industry.