The objective was to determine the additive and dominance genetic variances and the broad- and narrow sense heritabilities of eleven traits in sunflower hybrids obtained from drought tolerant inbred lines. There were 32 hybrids that were evaluated in irrigation, drought and rainfed conditions. The N.C Design II was used for environments, male and female factors. Additive variance was more important than the dominance variance for the traits affecting the reproductive period, stem dry weight, total dry weight, and head weight. Dominance variance was more important for the days to beginning of flowering, days to end of flowering, days to physiological maturity, reproductive index, plant height, leaf dry weight and achene yield. All traits reached the limit of selection in consequence to their very low genetic variance, and the level of endogamy of the lines was adequate to test them in hybrid combinations. The very low narrow sense heritability values observed in all traits reflected the low proportion of total genetic variance and the varied environmental conditions. The traits with lowest heritabilities were those related to the reproductive ability, while the traits with higher heritabilities were those associated with biomass production and distribution. The usefulness of the line-hybrid correlations to select lines per se depended of the amount of the additive variance, the control of environment and the distribution of genetic variances among the female and male lines.