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

USDA-N6006 soybean [Glycine max (L.) Merr.] (Reg. no. GP-527, PI 704140) is a conventional F₄–derived early maturity group (MG) VI germplasm jointly released by USDA-ARS and North Carolina Agricultural Research Service in 2023. USDA-N6006 is the first MG VI, publicly released germplasm that 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 1 day earlier than NC-Dunphy and exhibited similar lodging scores. Over 5 years of testing in North Carolina (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 North Carolina. 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 United States.