Fig. 3. Association of linolenic acid phenotype with FAD3 genotype in segregating BC₁F₂ seeds derived from a backcross (SS97–6946 x [SS97–6946 x IA3017]). Sixty-one BC₁F₂ seeds were chipped for fatty acid analysis with the remainder of the seed germinated and then subjected to genotyping for A29 or wild-type alleles of GmFAD3A, GmFAD3B, and GmFAD3C. It was not possible to distinguish Aa from AA genotypes. Samples were organized by increasing linolenic acid concentration. Black diamonds () represent soybean lines containing homozygous GmFAD3A mutant alleles and any combination of wild-type or mutant GmFAD3B and GmFAD3A alleles (aaxxxx). Circle symbols () represent soybean lines either heterozygous or homozygous wild-type for the GmFAD3A allele (Aa or AA, designated A?). The black square () represents the only line with the complete homozygous mutant genotype (aabbcc). The black triangle () represents the only line with a genotype of aaBbcc. No lines were identified which had the alternate genotype, aabbCc. Circles with gray shading indicate those lines which had either Aabbcc or AAbbcc genotypes (A?bbcc). Other selected genotypes are identified with arrows, and the genotype is listed.