Profiling of seed fatty acid composition in 1025 Chinese soybean accessions from diverse ecoregions

The stability of soybean (Glycine max L. Merrill) oil is determined mainly by its fatty acid (FA) composition. We evaluated the FA composition of 1025 Chinese soybean accessions collected from diverse ecoregions and grown in multiple locations and years. We observed highly significant differences (P < 0.001) between accessions in palmitic acid (PA), stearic acid (SA), oleic acid (OA), linoleic acid (LA), and linolenic acid (LNA) contents. Growth year affected (P < 0.001) the abundance of all FAs except PA. The mean PA, SA, OA, LA, and LNA contents were 12.2%, 3.8%, 21.5%, 54.2%, and 8.3%, respectively. The geographical origin of the accession influenced seed FA composition, indicating that accessions originating in each ecoregion tend to have distinct FA composition. We observed significant positive correlations among the three locations and between the two years, suggesting the high heritability and stability of individual accessions across contrasting environments. We also observed a relatively high negative correlation between the contents of OA and both LA and LNA (r = −0.90 and −0.59, respectively, each significant at P < 0.001), providing a potential entry point for developing strains producing oil with higher OA and lower LA and LNA levels. These would be appropriate for specialized use in the food industry. Our results will be useful in breeding soybean with improved quality to meet human nutritional and industrial needs.