Soybean seed oils contain approximately 23% oleic acid, and elevated amounts of oleic acid help prevent cardiovascular diseases and improve the quality of the oil. Chemically, it helps maintain the oxidative stability of oil; hence, soybean breeders primarily seek to increase its concentration for improved oil quality. As soybean seeds with mutant alleles of FAD2-1A and FAD2-1B genes have been reported to produce approximately 80% of oleic acid, a mutant population was developed from an ethyl methanesulfonate (EMS)-induced soybean cultivar (Pungsannamul). From this, a new mutant allele of FAD2-1A was identified using mutant lines with elevated oleic acid levels and the pooled-DNA sequencing method. This study identified PE529 as the allele with >40% oleic acid carrying the novel allele of the FAD2-1A gene. The single nucleotide polymorphism (SNP) in PE529 also induced the conversion from tryptophan to a premature stop codon at position 293 in the amino acid sequence (W293STOP). The inheritance analysis showed that the elevated oleic acids in PE529 were attributed to the fad2-1a W293STOP allele. In this study, seeds capable of producing approximately 80.0% oleic acid were identified from F2 populations where fad2-1a W293STOP and fad2-1b alleles were segregated. Hence, soybeans with novel alleles are useful genetic resources to improve soybean oil quality in breeding programs.

The number of four-seeded pods is a plant trait that is of great interest in terms of increasing soybean production. The objective of this study was to understand the agronomic characteristics of four-seeded pods of FS1159, which contain a significantly higher ratio of four-seeded pods than do other genotypes. FS1159 showed a significantly lower ratio of one-and two-seeded pods and a significantly higher ratio of three-(39.6%) and four-(11.3%) seeded pods than did the four check soybeans. The average values of the traits of FS1159 in this study were: plant height, 58.1 cm; the number of nodes, 15.7; the number of branches, 6.5; and 100-seed weight, 20.3 g. These results indicate that FS1159 can be used as a new genetic resource to explore the traits of four-seeded-pod and improve the soybean yield.

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