GENETIC-CONTROL OF FATTY-ACID COMPOSITION IN SEED OIL OF SINAPIS-ALBAL

Inheritance of fatty acid composition was studied in an F1 diallel cro ss in Sinapis alba. Crosses were made among accessions having contrast ing amounts of oleic (C18:1) and erucic (C22:1) acid. Concentrations o f oleic, linoleic (C18:2), eicosenoic (C20:1) and erucic (C22:1) acids were determined by gas-chromatography for each mating combination. Ge netic analysis confirmed that the composition of the fatty acids was c ontrolled mainly by the nuclear genes of the embryo. Additive gene act ion with partial dominance for the reducing alleles was noted for olei c and linoleic acids, while erucic acid showed an additive mode of inh eritance with partial dominance for the enhancing alleles. Positive he terosis was demonstrated for eicosenoic acid content. Erucic acid cont ent was strongly negatively correlated with oleic acid, suggesting a g enetic interdependence between the two fatty acids. Broad-sense and na rrow-sense heritability estimates for each of oleic, linoleic and eruc ic acids were very high, due to low between-plants non-genetic compone nt of variance.