Registration of USDA-N6006 germplasm combining high yield, flood tolerance, and elevated oil content

Authors: Mian, Rouf; CUNICELLI, MIA - Former ARS Employee; CARTER, THOMAS - Former ARS Employee; Villagarcia, Margarita; Fallen, Benjamin

Submitted to: Journal of Plant Registrations
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/6/2023
Publication Date: 2/24/2024
Citation: Mian, R.M., Cunicelli, M., Carter, T., Villagarcia, M.R., Fallen, B.D. 2024. Registration of USDA-N6006 germplasm combining high yield, flood tolerance, and elevated oil content. Journal of Plant Registrations. http://doi.org/10.1002/plr2.20358.
DOI: https://doi.org/10.1002/plr2.20358

Interpretive Summary: The United States is one of the largest soybean producers in the world. Production and yield have increased over the last two decades. The two major inputs to that have been attributed to the increase in soybean productivity are improvements in yield potential and improvements in agronomic practices. Going forward it is important that new cultivars and germplasm have high yield potential in favorable environments, but also perform well in high stress environments. Increased heavy precipitation has led to an increase in the severity of flood stress. Flood stress at any growth stage may result in substantially reduced yields. This indicates the need for improved tolerance to weather extremes for greater resilience in soybean production. USDA-N6006 is a conventional (non-GMO) soybean germplasm jointly released by the U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS) and North Carolina Agricultural Research Service in 2023. USDA-N6006 is the first maturity group (MG) VI, publicly-released germplasm which combines flood tolerance with high yield, lodging resistance and elevated seed oil. The yield of USDA-N6006 is similar to high-yielding, lodging-resistant check cultivars and has been shown to exhibit superior flood tolerance when compared to previously identified flood tolerant cultivars. USDA-N6006 was not intentionally bred to be flood tolerant and identified as such only through an extensive screening of ‘in house’ USDA breeding lines. USDA-N6006 and most of its antecedents are unique in that they are derived from unreleased breeding lines developed at the flood prone Tidewater Research station in NC. Inadvertent selection for flood tolerance may have been a part of the USDA’s long-term breeding effort to improve yield. Seed oil content of USDA-N6006 is similar to that of elevated seed oil cultivars and higher than cultivars exhibiting an average oil content. The exceptional combination of high yield, unique pedigree, flood tolerance, lodging resistance and elevated seed oil in USDA-N6006 makes it an important resource for improvement of U.S. soybean.

Technical Abstract: USDA-N6006 soybean [Glycine max (L.) Merr.] is a conventional F4 -derived early maturity group (MG) VI germplasm jointly released by the U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS) and North Carolina Agricultural Research Service in 2023. USDA-N6006 is the first MG VI, publicly-released germplasm which combines flood tolerance with high yield, lodging resistance and elevated seed oil. Over 19 environments of the MG VI USDA Southern Uniform Soybean Trials (2017-2018), seed yield of USDA-N6006 (3393 kg ha-1) was similar to high-yielding lodging-resistant check cultivars NC-Dunphy (3427 kg ha-1) and NC-Dilday (3475 kg ha-1). It matured one day earlier than NC-Dunphy and exhibited similar lodging scores. Over five years of testing in NC (2016-2019), USDA-N6006 exhibited very robust flood tolerance. Mean flooding scores were numerically or statistically (p<0.05) superior to the four flood tolerant controls at both V4 and R1 growth stages. USDA-N6006 was not intentionally bred to be flood tolerant and identified as such only through an extensive screening of ‘in house’ USDA breeding lines. USDA-N6006 and most of its antecedents are unique in that they are derived from unreleased breeding lines developed at the flood prone Tidewater Research station in NC. Inadvertent selection for flood tolerance may have been a part of the USDA’s long-term breeding effort to improve yield. Seed oil content of USDA-N6006 (237 g kg-1) was similar to that of elevated seed oil cultivar NC-Dilday, but significantly higher than NC-Dunphy (228 g kg-1) in the Uniform Trials. Seed protein content and estimated meal protein contents of USDA-N6006 (389 g kg-1 and 46.4%, respectively) were similar to that of NC-Dunphy. USDA-N6006 should be excellent parental stock for applied breeding in the southern USA.