Identification of RAPD markers linked to the loci controlling erucic acid level in rapeseed

Abstract

The recent development of the industrial use of rapeseed oil rich in erucic acid has led to increased interest in the improvement of the high-erucic-acid (50–60%) varieties and to research towards genotypes containing a very high erucic acid content. This trait is controlled by two genes with additive effects. The low-erucic-acid trait was relatively easily introduced through backcrosses into various backgrounds because the zero-erucic-acid homozygotes were clearly identified in the segregating populations. To select for high erucic acid level is more difficult because of the partial overlap of the high-erucic-acid homozygous class and the intermediate one, containing heterozygotes. In order to help conventional breeding, RAPD markers were used to map the two genes involved in determining the erucic acid content in a doubled haploid progeny derived from a ‘low x high’ erucic acid F1 hybrid. The two genes were successfully localized in two independent linkage group, through a QTL approach. A close association was found between individual plant genotypes and the erucic acid content of the doubled haploid progeny, and it was shown that the two genes do not contribute uniformly to the C22:1 level. The value of molecular gene mapping of such a trait in a conventional breeding programme is discussed.