Palmitic acid is one of the two major saturated fatty acids of soybean [Glycine max (L.) Merr.] oil that is closely related with physical, chemical and nutritional qualities. The average pahuitic acid content in the seed oil of common cultivars is 11.0%. Soybean mutants with both reduced and elevated palmitic acid have been developed. Previous studies had shown that reduced palmitic acid in a mutant C1726 and elevated palmitic acid in a mutant C1727 were respectively controlled by fap1 and fap2 alleles, and reduced palmitic acid in a nrutant J3 was controlled by sop1 allele. The objective of this study is to determine the genetic relationships of sop1 allele in J3 with fap1 and fap2 alleles in C1726 and C1727, respectively. Reciprocal crosses were conducted for J3 × Bay, C1726 × Bay, J3 × C1727 and J3 × C1726. No maternal effect for palmitic acid content was observed from the analysis of reciprocal F₁ seeds in any of the crosses. The data for palmitic acid content in F₂ seeds of J3× Bay and C1726 ×Bay fitted a 1:2:1 ratio. The segregation observed from the analysis of F₂ seeds of J3 × C1727 fitted the ratio of 1:14:1 and of J3 × C1726 fitted the ratio of 3:10:3. The F₂ segregation ratio and the segregation of F₃ seeds from F₂ plants of these crosses indicated that allele for palmitic acid in J3 was at a different locus from the alleles in C1726 and C1727. The segregant with the genotype sop1sop1fap1fap1 from J3 × C1726 has an average 3.5% palmitic acid and therefore, it is considered as an important germplasm that would be an advantage for soybean oil with better physical, chemical and nutritional qualities.