Plant & Animal Genome VI Conference

PA9

A GENETIC MAP OF MEADOWFOAM: GENES AFFECTING SEED OIL FATTY ACID COMPOSITION

Department of Crop and Soil Science, Oregon State University, Corvallis, OR 97331 USA.

Meadowfoam (Limnanthes alba Benth.) seed oil is a source of erucic acid and three novel very-long-chain (C₂₀ and C₂₂) mono- and di-unsaturated fatty acids. We are producing a genetic map for meadowfoam (x = 5) using intersubspecific (L. alba ssp. alba x L. alba ssp. versicolor) backcross progeny segregating for self-pollination, fatty acid content, oil content, growth habit, seed yield, and a variety of morphological traits. The initial map is being built using AFLPs. F₂ and backcross (BC) progeny were assayed for fatty acid content using gas chromatography. The L. alba ssp. alba parent produced 8% erucic acid and 30% dienoic acid, whereas the L. alba ssp. versicolor parent produced 24% erucic acid and 9% dienoic acid. A dominant gene affecting erucic and dienoic acid content segregated in these populations. The phenotypic distributions for the F₂ (79:21) and backcross (90:90) progeny were not significantly different from the expected distributions (3:1 and 1:1, respectively) for a single dominant gene (p = 0.48 for the F₂ and p = 1.0 for the BC). Erucic acid varied from 5 to 16% and dienoic acid varied from 13 to 29% among dominant class F₂ progeny. Within class phenotypic differences may have been caused by non-genetic factors or genes with quantitative effects. We are proposing to map QTL affecting fatty acid composition and a variety of agronomically and economically important traits in the backcross population.