Increased nitrogen fixation and remobilization may increase seed protein without a yield penalty in a soybean introgression line

ABSTRACT

Development of soybean [Glycine max (L.) Merr.] varieties with high seed protein concentration are hindered by a negative correlation between seed protein and yield. “Benning HP,” a genotype that breaks this tradeoff, contains an introgressed high-protein allele. Field and growth chamber experiments were conducted to identify N flux(es) that enable Benning HP’s increased seed protein without a yield penalty. When the N source was completely controlled, Benning HP could fix more N than its recurrent parent, but this depended on the rhizobium strain and plant developmental stage. In the field, Benning HP remobilized N from its leaves at a higher rate than its recurrent parent during seed fill in only one of the years studied. These results demonstrate that Benning HP has higher potential N fixation and N remobilization from vegetative tissue compared to its lower protein parent, but the expression of those traits may depend on environment and sink control.

KEYWORDS:

• nitrogen fixation
• nitrogen remobilization
• seed protein
• soybean

Acknowledgments

We thank Thomas E. Carter Jr., Paul Cook, Amy Niewoehner, Heather Sims, Jason Pleasant, Cory Callahan, and John Graeber for assistance with planting, tissue sampling, and harvest. We thank Cathy Herring and Travis Lassiter at Central Crops Research Station for field management. We thank Zenglu Li for generously sharing seed for these studies.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the USDA-ARS (United States Department of Agriculture Agricultural Research Service) project number [6070-21220-069-00-D].