Palmitic acid, a 16-C saturated fatty acid, is important in the production of margarine, shortening, and other fat products. This study was conducted to determine the inheritance of ethyl methanesulfonate-induced high palmitic acid (278 g kg-1) in a tlax (Linum usitatissimum L.) mutant (E67) and to determine the feasibility of combining this elevated palmitic acid trait with a reduced linolenic acid trait of another mutant (E1747), both derived from ~McGregor' flax. The E67 mutant also possessed elevated levels of palmitoleic acid (48 g kg-~). Reciprocal crosses of E67 × McGregor and E67 × E1747 were made. Gas chromatography analyses of fatty acids from seed oil of and backcross populations indicated that the control of the high palmitic and palmitoleic acid character in E67 was the result of the pleiotropic effect of a single additive gene. The study confirmed that the control of the deficient linolenic acid trait in E1747 was by two independent recessive genes. Neither gene was linked to the high palmitic acid locus. Combination of the mutant traits in E67 and E1747 was therefore possible. Quantitative ~H-nuclear magnetic resonance analysis revealed that the mutant allele in E67 had no effect on oil content, whereas in E1747, an increase of = 100 g kg-~ was observed under phytotron conditions. F~ LAX is noted for the high quality drying oil produced in its seeds. This is the result of the high content of ¢t-linolenic acid (= 500 g kg-1) in linseed oil, which is used industrially for manufacturing paints, stains, inks, lacquers, varnishes, linoleum, etc. With the aim to developing edible linseed oil with a reduced linolenic acid content of <3 g kg-1 (for flavor stability), Rowland and Bhatty (1990) treated 'McGregor' flaxseed (a Canadian flax cultivar) with ethyl methanesulfonate (EMS). Flax mutants with reduced levels of linolenic acid (E1747) and increased levels of palmitic acid (E67) were among the several mutants that were isolated. Rowland (1991) reported that linolenic acid level of E1747 was 20 g kg-1 and that the character was controlled by recessive alleles at two independent loci. Similar results were obtained by Green (1985) in a low-linolenic acid genotype, which resulted from a cross between two mutants, derived from chemical mutagenesis of the Australian flax cultivar Glenelg. The palmitic acid level in the seed oil of E67 was ~280 g kg-1. Palmitic acid, a 16-C saturated fatty acid, is important in the production of margarine, shortening, and other fat products (Vies and Gottenbos, 1989

Mutagens [e.g. EMS (ethyl methane sulphonate)] are sometimes used to generate variability in oil crops when variability is lacking in natural populations, or when strong interspecific crossing barriers prevent hybridization with relatives. It is imperative to conduct genetic studies on beneficial mutants before they can be effectively used in a breeding program. This study was conducted to study the inheritance, and characterize two "apparent" low linolenic acid EMS-induced McGregor flax mutants (E1929 and E1536) that appeared to be quite different from E1747, a linolenic acid deficient McGregor flax mutant which has been extensively studied. Diallele crosses involving 1) E1929, E1536, and McGregor, and 2) E1929, E1536, and E1747 were made. Gas chromatography analyses of fatty acids from seed oil of F1 and F2 populations indicated that E1929 resulted from a reduction in Δ15 desaturase activity, and that the control of the trait is by a single recessive gene. The E1929 gene appears to be allelic to one of the two genes possessed by E1747. E1929 was characterized as a "moderately low linolenic-high oleic acid mutant". E1536 could not be characterized with the available data. Key words: flax, fatty acids, linolenic, Linum