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ARS Home » Southeast Area » Raleigh, North Carolina » Soybean and Nitrogen Fixation Research » Research » Research Project #447410

Research Project: Yield Limitations of Soybean Varieties Under Drought: Identifying and Overcoming Weaknesses

Location: Soybean and Nitrogen Fixation Research

Project Number: 6070-21220-070-074-A
Project Type: Cooperative Agreement

Start Date: Oct 1, 2024
End Date: Sep 30, 2025

Objective:
Objective: 1a). Germplasm and cultivar development: a) Develop and release drought-resilient germplasm and high yielding varieties. 1b). Incorporate high oleic acid and high protein genes into elite drought-resilient breeding stock. Objective: 2a). Gene discovery and genetic marker development: a) Identify and incorporate newly discovered drought tolerance genes (slow wilting and beneficial root traits) into high-yielding backgrounds. Objective: 3). Improve drought screening and selection.

Approach:
1a). In this project, the Cooperator will evaluate 60-70 UGA advanced breeding lines under rain-fed conditions for yield, wilting-canopy trait as well as other agronomic traits in Midville, GA. These lines will also be yield-tested under irrigated condition in other environments. The Cooperator will genotype these lines with 6k DNA markers to determine the diversity of these lines and impact of the canopy wilting trait on yield. Using the germplasm with slow canopy wilting trait as parents, crosses will be made each year to incorporate the slow canopy wilting trait into our breeding pipeline in MGs VI, VII and VIII 1b). Previously the Cooperator identified the slow canopy wilting QTLs from PI 416937 and PI 471938. In this project, the Cooperator plan to introgress these QTLs or slow canopy wilting traits into high oleic or high protein elite lines that we developed to combine drought resiliency with high-oleic and high-seed-protein traits. 2a). Based on GWAS-QTL results from an association panel consisting of over 200 diverse lines in MG VI, VII and VIII for carbon isotope discrimination, and canopy wilting trait, we identified 19 PIs with good slow canopy wilting trait in multiple year tests. Two populations have been advanced to RILs derived from two PIs with best slow canopy wilting ratings. In 2025, the RIL population will be evaluated for canopy witling and other traits to map novel QTL of slow canopy-wilting and drought tolerance and to determine the effects of these QTLs on drought tolerance. 3). Using a rainout shelter, the Cooperator plans to screen the developed soybean cultivars and a strong pipeline of advanced materials which were derived from slow-canopy-wilting lines PI 416937, PI 471938 as well as NILs. Sensing and imaging technologies will be used to evaluate drought tolerance under the rainout shelter.