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Research Highlights

Research Highlights
Developing and Characterizing Soybean Germplasm with Increased Oil While Maintaining Protein and Yield

By Kyujung Van, The Ohio State University

The recent U.S. FDA ban on partially hydrogenated oil (PHO) as a food additive, and other factors, has significantly reduced the market share for soybean in the oilseed market. Within this challenge is the opportunity
to develop new soybean lines with specific oil characteristics and to restore and even expand the market for soybean oils. For example, omega-3 fatty acids for human dietary needs are currently supplied mainly by fish oil, but providing this and other essential fatty acids in a vegetable oil such as soybean would significantly expand the market for this land-based product. 

The soybean market has shown interest in high oleic soybean oil and potentially other high-value oil compositions. One way to maximize the value per acre is to develop new cultivars that have high oil content without decreasing either protein content or overall yield. The ultimate goals of this project are to develop soybean germplasm with ≥ 20.5% seed oil concentration (at 13% moisture) while maintaining protein concentration (≥ 35%) and yield. Another goal is the development of transgenic soybeans with modified oil components to develop a high-quality soybean for use in aquaculture and human food applications. To this end, the project was funded for $483,451 in 2019. 

The negative correlation between protein concentration and oil concentration in soybean has made it difficult to develop soybean cultivars with increased concentrations of both components. In order to break this connection, effort was made to identify the genomic regions that control both seed protein and oil concentrations through “trait-specific” alleles — those that contribute to one trait without impacting the other trait. Over 600 plant introductions (PIs) were selected from the USDA Soybean Germplasm Collection for their agronomic characteristics, as well as their protein and oil contents. A genome-wide association approach was used for the identification of alleles for both protein and oil. A genetic region on chromosome 5 was identified which increased seed oil with no effect on protein content as well as a second genetic region on chromosome 10 which increased seed protein content with little effect on oil content. 

The ambitious metric for this program was to develop soybean germplasm with ≥ 20.5% seed oil concentration (at 13% moisture) while maintaining protein concentration (≥ 35%) and yield. (See yellow quadrant in Figure 1.)
The researchers continually came very close and recommend that slightly lower levels are more practical at this time (20% oil; 34.5% protein). (See orange quadrant in Figure 1.) Even at this level, a 47.5% meal will be produced.

Figure 1. The relationship between protein and oil.

The efforts in this program have already led to the development of cultivars, varieties and germplasm lines with elevated seed oil concentration without a reduction in protein or yield. The lines range in maturity from Maturity Groups II-VI. Included are six released cultivars, one marketed by the Missouri Foundation Seed program and five licensed by private companies for commercialization. The cultivars have 19-21.1% oil, 33.2-34.6% protein and high yields (≥ 100% o check cultivars). Adoption of varieties that meet these goals by private breeders and growers would greatly increase the quantity of meal and oil produced.

Figure 2. Soybean seed embryos overexpressing genes targeting the co-synthesis of EPA and DHA, astaxanthin and tocotrienol.

Transgenic strategies are being explored for the development of value-added essential fatty acids in soybean seeds. These include the synthesis of very long chain fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), coupled with production of a high-value carotenoid, astaxanthin and tocotrienol. These modified soybeans hold potential as ingredients for aquaculture feed, human food and nutraceutical applications.

There is an immediate opportunity from this program in ensuring lines developed are commercialized so the value to the farmer is realized. Long-term opportunity is to continue to push the envelope toward increased protein and oil in the same bean. In addition, the research will advance understanding of fatty acid pathways in soybean and ultimately will facilitate the development of soybean with innovative oil composition. These enhancements will enable soybean to expand into new markets and new uses.

This project was funded by the soybean checkoff. To find research related to this research highlight or to see other checkoff research projects, please visit the National Soybean Checkoff Research Database.