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Research Highlights

Research Highlights
Improvement of Soybean Protein in Upper Midwest Germplasm

By Nadia Krasheninnik, Corteva Agriscience

Over the past several decades, the protein levels in soybeans have shown a small, but significant, decline. The decline in soybean protein was the result of commercial varieties being selected for their yield overall, rather than protein content. A contributing factor was the significant expansion of soybean production in the U.S. into the Upper Midwest region, since the environmental conditions in that region often result in slightly lower total crude protein content.

This project allowed Corteva Agriscience to use their proprietary methodologies to improve the protein content in maturity groups suitable for growing in the Upper Midwest region, including Minnesota, North Dakota, South Dakota, and parts of Iowa and Nebraska — mainly maturity groups 0, I and II. This was accomplished through selective breeding of higher-protein, earlier-maturity and high-yielding soybean lines. 

The first crosses between elite, high-yielding soybeans and high-protein parental lines were made in the spring of 2016. This work officially became a USB-funded project in the fall of 2017, after the initial crosses showed potential. Each season, the most promising lines that had good yield and were capable of producing a calculated meal with at least 47.5% protein were advanced to the next phase of testing. 

Testing for protein, oil and other components lags behind initial harvest and yield analysis. Samples taken in the fall of 2018, prior to the 2019 field trials, were analyzed using Near Infrared (NIR) spectroscopy. Predicted protein content for over 11,000 samples averaged 34.5%, and ranged from 28.9% to 40.2% (all reported on a 13% moisture basis). Compositional predictions and spectral analysis were used to identify a subset of samples that were submitted for reference chemistry. Data from the reference chemistry was used to validate and extend predictive models. To enable studies into the relationship between protein and essential amino acid content, a further subset of samples was identified and submitted to the University of Missouri for reference analysis. 

While the compositional analysis was underway, decisions were made regarding which lines would be advanced to elite, wide-area yield-testing trials across North Dakota, Minnesota, South Dakota and Eastern Canada for the spring and summer of 2019. This material was expected to provide the most comprehensive dataset for this project, since it encompassed multiple locations. Unfortunately, extremely challenging harvest conditions in the fall of 2019 did not allow the harvest and data collection from all locations planted in the Upper Midwest. Nevertheless, sufficient material was harvested to provide a robust dataset, from which final conclusions will be drawn. 

December 2019 was the end of the official collaboration between Corteva Agriscience and USB on this project. The protein and oil content of all seed samples that could be harvested, along with the appropriate checks, have been determined by NIR. This data is currently being analyzed, and conclusions will be available in the final report. 

This project was a test case for Corteva Agriscience’s proprietary breeding tools, as applied to soybean protein composition. It provided additional information on the stability of the protein trait in the Upper Midwest environment. These learnings will inform future innovative products that will benefit growers and other producers.