Determination of the fatty acid and triglyceride compositions of the F~ (Elaeis guineensis • E. oleifera), F a and the backcross hybrid mesocarp oils demonstrated that most fatty acid and triglyceride compositions of oils from hybrid palms are intermediate between those of their respective parentals. These data, as well as the acyl group (samrated/palmimte and unsaturated/oleate) distribution of trigtycerides of the F 2 mesocarp oils provide genetic proof for codominance in the F a generation which shows a characteristic segregation into the co-domlnance ratio of 1:2:1 (i.e., 1 E. guineensis: 2 F 1 hybrid: 1 E. oleifera). Similar analyses into the backcross hybrid mesocarp oils on the whole confirmed co-dominance when the backcross ratio of 1:1 was obtained. These remits are used to develop the Co-Dominance Theory of Elaeis palm hybridization which makes successful predictions for mesocarp oils from the different hybrid palms. ABSTRACTThe fatty acid and sterol compositions of different parts of Malagasy zebu (Bos indicus) were evaluated. Investigation by gas liquid chromatography using Carbowax 20 M revealed 35 fatty acids, mainly palmitic (24-27%), stearic (13-24%), and oleic (25-37%) acids. Oddnumbered, iso and anteiso fatty acids were also detected. Small differences in composition were observed between the hump and the kidney fats of B. indicus. Comparison between industrial tallow of B. indicus and B. taurus revealed slight differences in the stearic/ oleic acid ratio (0.83 and 0.46, respectively). An OV 17 column was used to separate 9 sterols, mainly cholesterol (89-98%). fl-Sitosterol was also found at lower concentrations in all the samples.