Abstract:   By using a genetic model including additive and dominance effects and their interaction with environments, 7 agronomic traits were analyzed for a diallel design in 4 environmental conditions with 14 flue-cured tobacco varieties (or breeding lines) and their 41 F₁ crosses. It was revealed that additive effects were the major genetic component for plant height, internode length, and width of leaves. Number of leaves and length of leaves were mainly controlled by dominance × environment interaction effects. Additive × environment interaction effects and dominance × environment interaction effects played a major role for girth of stem. Yield performance was mainly controlled by additive effects and dominance × environment interaction effects. The varieties adapted to local environments tended to have highly positive additive effects. Dominance effects and the dominance × environment interaction effects could perform differently in positive or negative direction for many crosses. The breeding program for hybrids should consider the adaptation of hybrids to specific ecological environments. The analysis of correlation among agronomic traits indicated that most of phenotypic, genotypic, additive and dominance correlation coefficients were positive. Additive correlations were predominance in genetic correlations for most pairs of traits. Yield can be improved by indirect selection on plant height.