A dominant gene decreases erucic and increases dienoic acid in the seed oils of meadowfoam subspecies

Meadowfoam (Limnanthes alba Benth.) seed oil is a source of erucic acid (22 :1 Delta 13) and novel very long chain fatty acids. The fatty acid profiles of L. alba subspecies are distinctly different. L. alba ssp. versicolor pr oduces significantly more erucic acid and significantly less dienoic acid ( 22:2) than L. alba ssp. alba. The L. alba ssp. alba profile is the standard for certain meadowfoam oil markets. Because changes in the profile could a ffect meadowfoam oil markets, we completed a study to elucidate the genetic s of erucic and dienoic acid content differences in the subspecies. The Pat ty acid contents of F-2 and F-3 progeny from an L. alba ssp. alba x L. alba ssp. versicolor (P-1 x P-2) cross were assayed by gas chromatography. P-1 produced 81 g kg(-1) erucic acid and 297 g kg(-1) dienoic acid, whereas P-2 produced 242 g kg(-1) erucic acid and 86 g kg(-1) dienoic acid. There were two non-overlapping erucic by dienoic acid phenotypic classes among 100 F- 2 progeny. The phenotypic distribution (79:21) was not significantly differ ent from 3:1 (P = 0.48); thus, these progeny segregated for a dominant gene . This was verified by F-3 progeny tests. Unless markets can tolerate the r ange of fatty acid compositions found in L. alba germplasm, cultivars with the L. alba ssp. alba fatty acid profile must he developed.