Low linolenate sources at the Fan locus in soybean lines M-5 and IL-8

Reduction of linolenic acid content in soybean [Glycine max (L.) Merr.] oil is associated with improved odor and flavor characteristics. The mutant M-5 and line IL-8, used in this study were identified with linolenic acid contents (4.63 % and 4.50 %, respectively) half that of Bay (8.02 %) but similar to that of C1640 (4.58%). The objective of this study was to determine the inheritance of low linolenic acid content in IL-8, and to determine the genetic relationships among alleles controlling linolenic acid in M-5, IL-8 and C1640. Reciprocal crosses were made among M-5, C1640, IL-8, and Bay. The F₂ segregation ratio and the segregation of F₃ seeds from F₂ plants of M-5 x Bay, C1640 x Bay, and IL-8 x Bay indicated that M-5, C1640, and IL-8 have alleles at a single locus. The F₂ plants from the crosses of M-5 x IL-8, M-5 x C1640, and C1640 x IL-8, did not transgressively segregate indicating the low linolenic acid contents in M-5, IL-8, and C1640 were controlled by the same alleles. Therefore, the alleles in M-5, IL-8, and C1640 have been designated fan (M-5), fan IL-8), and fan C1640), respectively.