The present study was carried out at Sakha farm, Sakha Agricultural Research Station (SARS), Kafr El-Sheikh, Egypt, during the three summer seasons of 2017, 2018 and 2019. Four crosses of soybean, each with six populations (P1, P2, F1, Bc1, Bc2 and F2) were tested for yield and some growth attributes. The results showed that: Over dominance was observed for flowering date in crosses I and II, for maturity date and plant height in cross II and seed yield per plant in all crosses, while partial dominance was observed for the remaining crosses for most traits. Significant negative heterosis were detected for flowering date for mid-parent in the first cross, significant positive heterotic effects were detected for other traits.  The additive effect (a) was highly significant in positive or negative direction in all crosses for all traits, except in the four crosses for number of seeds per pod and 100 seed weight, crosses I and II for flowering date.  Additive x additive types of gene action were found to be significant for most traits of all crosses, also additive x dominance and dominance x dominance types of gene effects were found to be significant for most traits. High narrow sense heritability values were obtained for plant height and number of seeds per pod in the first cross. While, the lowest estimates was resulted for number of seeds per pod in the second cross, number of branches  per plant in the first cross and seed yield per plant in the fourth cross.