Novel Polyunsaturated Omega-3 Oil Genes from Wild Soybean.

Oils high in α-linolenic acid (ALA) have industrial uses such as lubricating oils and linoleum flooring. Typically, soybean [Glycine max (L.) Merr.] germplasm ranges from 7 to 11% ALA in seed oil but typically has lower ALA content than other seed oils used in this market. Introgressing novel alleles for high ALA from wild soybean (G. soja Sieb & Zucc.) has the potential to increase ALA content beyond that currently found in soybean. Wild soybean plant introduction PI 366122 (18% ALA) was hybridized with soybean cultivar N7103 (10% ALA) and the genetics and agronomics of elevated ALA were investigated. A F₄-derived line was identified which segregated for ALA. From this line, Heterogeneous Inbred Families (HIFs) were derived, all of which traced to a common F₇ plant. The 40 HIFs were tested in a 2-location, 2-replication trial. Five plants were sampled and phenotyped per plot to obtain a plot average for ALA. HIFs ranged from 12 to 16% in the trial. A genome-wide association study (GWAS) was conducted using the SoySNP50K iSelect BeadChip to identify genomic regions associated with elevated levels of ALA. Results will be presented. In a second study, the association between seed yield and ALA was investigated using three sets of HIFs, each of which traced to a common F₅ plant. Over 4 locations, replicated trials indicated that the association between the traits was variable. Two populations exhibited almost no genotypic correlation and a third showed a moderate negative correlation (-0.4) between the two traits. Yields of the HIFs were much lower than that of an adapted cultivar and, thus, the impact of high ALA on agronomic performance needs to be assessed in higher-yielding, elite backgrounds. However, it appears that the wild soybean may be a useful source of the high ALA trait.