The results of a biochemical and genetic research showed that there were significant differences in the examined biochemical parameters (enzyme activity and protein content), among the tested sunflower genotypes and their F1 hybrids. The inheritance of the examined characters was controlled by both additive and non-additive gene actions, as indicated by the results of variance analysis for general (GCA) and special combining ability (SCA). These results were in accordance with the results obtained for inheritance mode when the combinations were observed separately, where intermediate inheritance, full or partial dominance or heterosis occurred. The genotype SNRF-4 having the highest mean values of enzyme activity (NR, GS, GOGAT and GDH) and leaf protein content was also the best general combiner.It is, therefore, recommended to be a parent in hybridization for high protein content. There was a positive correlation between the enzyme activity (NR, GS, GOGAT and GDH) and leaf protein content.