All the [HOAC] lines derived from the Pervenets mutant carry a specific RFLP (oleHOS) revealed by an oleate desaturase cDNA used as a probe. The [LO] (linoleic) genotypes do not carry oleHOS, but another allele: oleLOR. We studied [HOAC] heredity in two segregating populations. In an F2 population, the [HOAC] trait co-segregated with oleHOS. In a recombinant inbred line F6 population, all [HOAC] RI lines carried oleHOS. The RI lines carrying oleHOS were either [LO] or [HOAC]. The absence of [HOAC] RI lines with oleLOR eliminated the occurrence of a recombination event between the locus carrying oleHOS and the locus carrying Pervenets allele. The [HOAC] trait is due to 2 independent loci: the locus carrying oleHOS allele and another locus. One allele at this other locus may suppress the effect of oleHOS allele on the [HOAC] trait. The existence of this suppressor allele has only been suggested for sunflower.