High-protein soybean lines with stable seed protein content under heat and drought stresses

Authors: KAKATI, J - Clemson University; Fallen, Benjamin; Armstrong, Paul; Yan, Shuping; BRIDGES, W - Clemson University; NARAYANAN, S - Clemson University

Submitted to: Journal of Agriculture and Food Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/16/2024
Publication Date: 10/16/2024
Citation: Kakati, J.P., Fallen, B.D., Armstrong, P.R., Yan, S.N., Bridges, W., Narayanan, S. 2024. High-protein soybean lines with stable seed protein content under heat and drought stresses. Journal of Agriculture and Food Research. 18. https://doi.org/10.1016/j.jafr.2024.101469.
DOI: https://doi.org/10.1016/j.jafr.2024.101469

Interpretive Summary: Soybean is the top-ranked source of protein meal worldwide. In the U.S. alone, 47 million metric tons of soybean meal was produced in 2022. Of those, 34.3 million metric tons were fed to poultry, swine, dairy and beef cattle, pets, and fish (aquaculture). However, the protein content in soybean has been declining for over a decade. Increasing the seed protein content in soybean will make it a more valuable feedstock and enhance its importance in the international market. Further, confirming the stability of the high-protein trait under environmental stresses is important to ensure climate resilience. The objectives of this study were to test whether recently developed high-protein soybean genotypes can maintain their high seed protein content under heat and drought stresses imposed during seed filling and to assess the changes in their oil composition (seed fatty acid contents) under stress conditions. The changes in seed protein and oil contents and oil composition of the high-protein genotypes under heat and drought stresses were assessed and compared against high-yielding released conventional cultivars, low-protein, heat-tolerant and heat-susceptible genotypes. We found that it is possible for high-protein genotypes to maintain high seed protein under heat and drought stresses. Additionally, high-protein genotypes were observed that did not exhibit a significant yield drag or decrease in oil content. The results of this study demonstrate the potential to develop new soybean varieties with enhanced nutritional value that are adapted to changes in the climate that can produce high heat and drought stress.

Technical Abstract: Soybean is an important crop globally used for human consumption and animal feed. A significant factor determining the value of soybean is the nutritional content. Increasing the seed protein content in soybean will make it a more valuable food and feedstock and enhance its importance in the international market. Due to this reason, developing high-protein soybean varieties is gaining increased industrial interest. To ensure profitable production, it is imperative to test the stability of the high-protein trait under environmental stresses. The objectives of this study were to test whether the high-protein soybean genotypes can maintain their high seed protein content under heat and drought stresses imposed during seed filling and to assess the changes in their oil composition (seed fatty acid contents) under stress conditions. The changes in seed protein and oil contents and oil composition of the high-protein genotypes under heat and drought stresses were assessed and compared against high-yielding released conventional cultivars, low-protein, heat-tolerant and heat-susceptible genotypes. We found that the high-protein genotypes NLM09-77, N16-9924, N14-7017, and Benning HP maintained their high seed protein contents under heat and drought stresses. Additionally, the high-protein genotypes N14-7017, NLM09-77, and Benning HP did not exhibit a significant yield drag or decrease in oil content. The results of this study demonstrate the potential to develop new soybean varieties with enhanced nutritional value that are adapted to changes in the climate that can produce high heat and drought stress.