Registration of USDA‐Max × Soja Core Set‐1: Recovering 99% of Wild Soybean Genome from PI 366122 in 17 Agronomic Interspecific Germplasm Lines

Abstract

USDA‐Max × Soja Core Set‐1 (USDA‐MxS‐CS1‐1 to USDA‐MxS‐CS1‐17 [Reg. No. GP‐417 to GP‐433, PI 689053 to PI 689069]) is a group of 17 interspecific breeding lines developed from the hybridization of lodging‐resistant soybean cultivar N7103 [Glycine max (L.) Merr.] with wild soybean plant introduction PI 366122 [G. soja Siebold & Zucc.]. These materials were released by the USDA‐ARS and the North Carolina Agricultural Research Service (March 2017) to expand the North American soybean breeding pool. The full‐sib breeding lines are 50% wild soybean by pedigree and developed through bulk breeding and pedigree selection. Marker analysis of 2455 well‐distributed polymorphic single‐nucleotide polymorphism loci revealed that individual breeding lines ranged from 21 to 40% alleles derived from wild soybean. Collectively, most of the wild soybean genome was transferred to the core set in that 5, 10, and 17 breeding lines captured 83, 98, and 99% of G. soja–derived polymorphic alleles. Physical linkage maps suggested that extensive recombination occurred between the G. max and G. soja genomes. The 17 breeding lines are well adapted to the southeastern United States, exhibited seed yield ranging from 75 to 97% of the domesticated parent, and are group VI or VII maturity. Some breeding lines displayed increased seed protein, oil, or methionine content, and all exhibited increased seed size as compared to the domesticated parent. The novel genetic diversity, positive agronomic performance, and improved seed composition of these lines suggest that they are valuable genetic resources for US soybean breeding.