U.S. farmers stand to benefit greatly from the advancements made in this project, particularly through the development of soybean varieties that can thrive in low-input production systems, reducing the need for costly fertilizers. The acquisition of 140 plant introductions (PIs) from over 10 countries, focusing on traits like salt tolerance and nitrogen fixation, expands the genetic diversity available for breeding programs. This could lead to the development of soybean cultivars better with enhanced nitrogen fixation efficiency, which is crucial for maintaining productivity under reduced fertilization. The identification of several PIs with high yield potential and desirable agronomic traits highlights new opportunities for improving yields, while ongoing research into root traits, such as total root length and surface area, could enhance resource uptake and boost crop performance. Variety development is already underway from a PI that has been identified for possessing a gene that enhances nitrogen efficiency by regulating nodulation specificity, which could lead to more efficient nitrogen uptake and improved overall plant health. Additionally, the correlation between nitrogen use efficiency (NUE) and salt tolerance indicates that salt-tolerant genotypes exhibit higher nitrogen accumulation, which is essential for maintaining productivity in challenging environments. By improving nitrogen fixation and developing varieties that require fewer inputs, U.S. farmers will benefit from reduced production costs and more sustainable farming practices, while maintaining high yields and crop quality.

This project has delivered key advancements in the development of soybean varieties with enhanced nitrogen use efficiency (NUE), salt tolerance, and higher yield potential, providing considerable benefits to U.S. farmers. Through the acquisition of 140 diverse plant introductions (PIs) from over 10 countries, valuable genetic resources have been identified, with a focus on traits such as enhanced nitrogen use efficiency and nitrogen fixation. Several PIs have shown high yield potential and desirable agronomic traits under low inputs, offering new possibilities for improving crop yields. Furthermore, research into root traits like total root length and surface area aims to boost resource uptake and overall crop performance. Notably, variety development is already underway from a PI identified for its nitrogen efficiency gene, which enhances nodulation specificity, leading to more efficient nitrogen uptake. In-field trials and greenhouse studies are evaluating these PIs and breeding lines under a range of conditions, particularly low-input systems. Results show that salt-tolerant cultivars exhibit better above-ground biomass and nitrogen accumulation, key factors for improving productivity in low-input environments. The project's focus on developing varieties that require less fertilizer input aligns with the goal of promoting sustainable farming practices while maintaining high yields. By enhancing NUE, salt tolerance, and root system development, this project offers U.S. farmers the tools to increase yields, lower production costs, and improve crop resilience, ensuring greater sustainability and profitability in the future of soybean production. More information on these highlights and additional highlights can be found in the final report.