MAPPING LOCI CONTROLLING THE CONCENTRATIONS OF ERUCIC AND LINOLENIC ACIDS IN SEED OIL OF BRASSICA-NAPUS L

The duality of plant oil is determined by its component fatty acids. R elatively high levels of linolenic acid reduce the oxidative stability of the oil. and high levels of erucic acid in the diet have been asso ciated with health problems. Thus, oilseed Brassica napus cultivars wi th low linolenic and low erucic acid contents are highly desirable for edible oil production. Tn order to identify genes controlling the lev els of erucic and linolenic acids, we analyzed the oil composition of 99 F-1-derived doubled haploid lines from a cross between 'Major' (hig h levels of erucic and linolenic acids) and cv 'Stellar' (low levels o f both fatty acids). A molecular marker linkage map of 199 loci for th is population was used to identify quanlitative trait loci (QTL) contr olling oil composition. We identified two regions that accounted for n early all of the phenotypic variation in erucic acid concentration and one region that accounted fur 47% of the variation in linolenic acid concentration. The QTL associated with linolenic acid concentration ma pped near a RFLP locus detected by a cDNA clone encoding an omega-3 de saturase, suggesting that the low linolenic acid content of 'Stellar' may be due to a mutation in this gene.