Registration of USDA-N7006 soybean germplasm with increased tolerance to drought stress and 37.5% pedigree from Asian accessions PI 416937 and PI 407859-2

Authors: Mian, Rouf; Robertson, Marta; Powell, Emily; CARTER, THOMAS - Former ARS Employee; Fallen, Benjamin

Submitted to: Journal of Plant Registrations
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/16/2023
Publication Date: 8/24/2023
Citation: Mian, R.M., Robertson, M.H., Powell, E., Carter, T., Fallen, B.D. 2023. Registration of USDA-N7006 soybean germplasm with increased tolerance to drought stress and 37.5% pedigree from Asian accessions PI 416937 and PI 407859-2. Journal of Plant Registrations. https://doi.org/10.1002/plr2.20323.
DOI: https://doi.org/10.1002/plr2.20323

Interpretive Summary: Drought is one of the biggest concerns in sustainable agriculture. It is predicted that in the coming years there will likely be an increase in the frequency and intensity of droughts. Soybean in the United States is particularly susceptible to drought because it is often grown under natural rainfall conditions. A sustainable approach to improve agronomic performance under drought conditions is to use conventional breeding methods to develop new drought-tolerant cultivars. However, the development of drought-tolerant soybean is impeded by the lack of genetic diversity in North American breeding stocks. The three main traits that have been identified to improve tolerance under drought stress in soybean are delayed-wilting or slow-wilting, sustained nitrogen fixation, and reduced transpiration. USDA-N7006 is a conventional (non-GMO) maturity group (MG) VII soybean germplasm released because of its drought tolerance, genetically diverse pedigree, and high yield potential. USDA-N7006 traces 37.5% of its parentage to soybean lines originating in Japan and South Korea. From 2015-2021, USDA-N7006 was evaluated in 57 environments across the Southeast yielding 97% of previously released high yielding soybean varieties. Over six drought stressed environments in North and South Carolina, USDA-N7006 exhibited very little wilting. USDA-N7006 maintains good yield under drought and non-drought stressed environments, making it a good candidate for soybean breeding and cultivation in non-GM production systems.

Technical Abstract: USDA-N7006 is a conventional (non-GMO) maturity group (MG) VII soybean [Glycine max (L.) Merr.] germplasm released jointly by the USDA-ARS and the North Carolina Agricultural Research Service in the spring of 2023. USDA-N7006 was released because of its drought tolerance, exotic parentage (37.5%), and high yield potential. USDA-N7006 traces 12.5% of its parentage to plant introduction (PI) 416937 from Japan and 25% to PI 407859-2 from South Korea. USDA-N7006 is the first North American soybean release derived from PI 407859-2. USDA-N7006 is an F4-derived germplasm from the hybridization of USDA breeding lines TCPR01-83 and N01-11136. From 2015-2021, USDA-N7006 was evaluated in 57 environments across the Southeast in the United Soybean Board (USB) Protein and Diversity MG VII Tests and the USDA Southern Soybean Preliminary and Uniform MG VII Tests. In the MG VII USDA and USB Protein and Diversity Tests, USDA-N7006 yielded 96% and 98% of the check mean, respectively. Over six droughted environments in North and South Carolina, USDA-N7006 exhibited less wilting (greater drought tolerance) than USDA-N8002, a previously released cultivar exhibiting drought tolerance. The unique pedigree, delayed canopy wilting under drought stress, and high yield of USDA-N7006 make it an excellent candidate for parental stock for soybean breeding programs aiming to improve drought tolerance.