INHERITANCE OF REDUCED LINOLENIC ACID CONTENT IN SOYBEAN SEED OIL

Linolenic acid is the unstable component of soybean [Glycine max (L.) Merr.] oil that is responsible for the undesirable odors and flavors c ommonly associated with poor oil quality. Two mutants, M-5 and KL-8, h ave been identified that have lower linolenic acid levels in the seed oil than the 'Bay' cultivar. Our objective was to determine the relati onships between the genetic systems controlling linolenic acid in thes e mutants. Reciprocal crosses were made between the mutants and 'Bay', and between the two mutants. No maternal effect for linolenic acid co ntent was observed from the analysis of F-1 seeds in any of the crosse s. The data for Linolenic acid content in F-2 seeds of M-5 x 'Bay' and KL-8 x 'Bay' crosses satisfactorily fit a 1:2:1 and 3:1 ratio, respec tively. For the M-5 x KL-8 cross, segregation observed from the analys is of F-2 seeds for linolenic acid content satisfactorily fit a ratio of 3 more than either mutant: 12 within the range of the two mutants: 1 less than either mutant. The segregation ratio of F-2 seeds and the segregation of F-3 seeds from F-2 plants indicated that M-5 and KL-8 h ave alleles at different loci that control linolenic acid content. The allele in KL-8 has been designated as fanx (KL-8) to distinguish it f rom fan (M-5). The low linolenic acid segregates with the genotype fan fanfanxfanx provide additional germplasm to reduce the linolenic acid content from the seed oil of soybean.