High yielding, non-nodulating isolines as a tool for improving soybean meal protein concentration
Sustainable Production
AgricultureGeneticsNitrogen fixation
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Larry C Purcell, University of Arkansas
Co-Principal Investigators:
Project Code:
Contributing Organization (Checkoff):
Institution Funded:
Brief Project Summary:
In 2017 we initiated backcross programs to transfer the non-nodulating trait from two different genetic sources, including the recessive rj1 allele, into a high yielding variety with glyphosate resistance. That effort has progressed to the point where we evaluate non-nodulating and nodulating near isogenic pairs in an early maturity group (MG) 4 during the summer of 2021. We have now begun a backcross program that is rapidly advancing nodulating/non-nodulating near isolines in high-yielding, modern genetic backgrounds with the Roundup Ready (glyphosate tolerance) trait across the MGs grown in the United States (MGs 0, 1, 2, 3, 4, 5, 6, 7, and 8).
Information And Results
Project Summary

Project Objectives

Project Deliverables

Progress Of Work

Final Project Results

The average protein concentration of soybean grain has steadily decreased over the past 20 years, threatening the value of the commodity. Soybean protein concentration is nominally reported as 40%, but average protein concentration today is 34% and is considerably lower than this in the northern US. Because protein production requires large amounts of nitrogen, management and genetic strategies to slow or reverse the decline in protein concentration require accurate methods to determine the relative contributions for the two sources of nitrogen nutrition - nitrogen fixation and soil mineral nitrogen. These measurements require the use of non-nodulating genotypes that are of similar maturity to nodulating cultivars being grown by farmers that also have similar yields when provided with adequate nitrogen fertilizer. Currently, there are no non-nodulating genotypes in any maturity group that are comparable to high-yielding cultivars grown today. This research project is creating a suite of nodulating and non-nodulating near isolines of soybean in each of the major maturity groups (MGs) grown in the US (MGs 0 through 8). These lines are a critical tool for developing management methods or cultivars with increased seed protein. We are finalizing release notes for MG 4 isolines that when fertilized heavily with nitrogen fertilizer have yield similar to commercial MG 4 cultivars. Isoline pairs for the other MGs are in advanced stages of development.

Benefit To Soybean Farmers

Outlined below are the steps needed to capture benefits from this project for all US soybean Farmers. University of Arkansas (Larry Purcell and Caio Vieira): The nine pairs of MG 5.4 isolines (BC3F2:4) harvested this fall will be increased in winter nursery for field evaluation in 2024. We plan to have experiments at two locations with these nine isolines plus the recurrent parent (R13-14635RR:0010) and Lee-nonnod. At both locations, 150 lbs N/acre will be applied at V6 and then again at R2. These experiments will guide the decision on which lines to release as germplasm late in 2024 or 2025. University of Minnesota (Aaron Lorenz): During the next year, we will focus on increasing seed quantities for field evaluation. Ideally, we could obtain some funding to genotype induvial plants with whole-genome markers to create pairs of NILs that are more isogenic to one another as determined by marker similarity. We also need to prepare a Journal of Plant Registration article to announce the availability of these NILs. University of Nebraska (George Graef): After our analysis of the 2023 initial yield results and other agronomic data, we will narrow down the selection of final isoline pairs that will be deposited in the USDA Soybean Germplasm Collection and available for distribution for further research. We will need another seed increase in 2024 to get sufficient amounts of seed for distribution to the soybean research community. We also plan a replicated, multi-location yield test of selected isoline pairs during 2024. Kansas State University (Bill Schapaugh): An initial set of MG4 non-nodulating releases should be completed in early 2024. These lines have been extensively phenotyped and genotyped. Seed increases in AR and KS should be adequate in quality and quantity to provide to the USDA Germplasm Collection. And, as already noted in previous reports, some of these initial non-nodulating lines and the recurrent parent have been distributed to several other researchers in other states. So, initial benefits from this work are being captured for US soybean farmers as this project continues. In KS, backcrossing has been completed using four additional recurrent parents, but phenotyping, some additional genotyping, and seed increases need to be completed on this material before additional genotypes are available for release. This work will require at least one more growing season and year, and perhaps two years to complete. University of Georgia (Zenglu Li): Soybean has the ability to obtain its own nitrogen through a symbiotic relationship with nitrogen-fixing bacteria, Bradyrhizobium japonicum. Nitrogen fixation in the plant eliminates the need for nitrogen fertilizers and is fundamental to seed protein composition development. The NILs, markers and mapping positions of Rj5 and Rj6 genes generated through this project will help soybean breeders/researchers understand the genetic controls of nitrogen fixation which could further help identify genotypes that increase yield. The genes and marker information will be useful tools for the soybean researchers to study the uptake and utilization of nitrogen in soybean plants and mechanism of nitrogen fixation.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.