2020
Soybean Nitrogen Metabolism: Investigating a Potential Link between Drought Tolerance, Yield, and Seed Composition
Category:
Sustainable Production
Keywords:
Abiotic stressAgricultureLand Use Water supply
Lead Principal Investigator:
Anna Locke, North Carolina State University
Co-Principal Investigators:
Project Code:
18-043
Contributing Organization (Checkoff):
Institution Funded:
Brief Project Summary:

Soybean seed composition is a focus for marketing and new variety development. However, composition typically changes under environmental stress. Seed protein content is usually limited by nitrogen availability and transport into the growing seed, and plant nitrogen metabolism is tightly linked with water availability. Thus, plant nitrogen use may be a key connection between drought tolerance in both yield and seed composition. This project builds on previous research, investigating plant nitrogen content under favorable (irrigated) conditions and drought (non-irrigated) conditions, and relating this to seed yield stability and seed composition stability in drought. This will help identify physiological and genetic targets for soybean breeders to develop varieties that maintain seed composition traits during drought.

Key Benefactors:
farmers, agronomists, extension agents, soybean breeders, seed companies

Information And Results
Project Deliverables

Final Project Results

Soybean varieties vary in their seed protein content and in drought responses. Drought typically lowers yield, but some varieties have more stable seed composition than others. This project investigated the interaction between drought responses, nitrogen metabolism, and seed protein. Year 1 had the mildest drought during the early seed fill period, and year 3 had the most severe drought. In year 4, drought was moderate, but in year 2, we experienced a more severe
drought during early seed fill, but this was followed by Hurricane Florence and more extremely wet weather during later seed fill, reducing the impact of the drought. The severe drought in year 3 occurred during the critical seed filling period. In the year with mildest drought, a few genotypes had lower seed protein content in the drought-stressed plots, while others had stable seed protein concentration. However, in the year with severe drought, most genotypes had
increased seed protein concentration in the drought stressed plots. Seed protein responses depend on the severity of stress, and seed protein had more variation among genotype in moisture stress responses than either yield or oil concentration. Based on these results, it may be possible to improve soybean seed protein responses to drought stress through soybean breeding. However, a negative tradeoff between yield responses and seed protein concentration responses to drought was observed.

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.