Ten tobacco varieties were intercrossed in all combination in 1993 in a Haif-diallel design and F1’s plus parents were transplanted in 1994 in a randomized complete blocks design with 4 replications. 11 quantitative and quality determinating traits were investigated.The variance analysis of results showed significant GCA and SCA for all and some traits, respectively.So, the additive and non-additive gene effects are involved with characters under investigation, but the portion of additive and heritable effects of genes are more important.Graphical analysis of results for number of leaves per plant, days form transplantation to flowering and resistance of varieties to root knot nematodes showed a partial dominance. Therefore, due to high amount of additive gene effects in genetic control of these traits, genetic advance for selection of these characters would be high.In the genetic control of traits such as plant hights, leaf area index, diy-leaf yield and resistance to Peronospora tabacina the overdominance gene effects in involved. Because of low heritability, genetic advance for selection of these characteristics would be poor.Graphical analysis for results showed that the partial dominance in genetic control of characteristics is involved. Therefore, because of high amount of additive gene effects of nicotine content and appearance of leaves, genetic advance for selection of these characters would be high.Although the additive gene effects in genetic control of sugar content is present, but the high amount of environmental effects and low heritability (29%), genetic advance for selection of this characteristics would be poor.
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