Six populations of three maize crosses were grown during the three growing seasons, 2016- 2018 at Ghazalla Agricultural Experimental Station, Fac. of Agric., Zagazig Univ. were evaluated for earliness characters and yield characters. The adequacy of genetic model of gene effects for the evaluated characters were estimated. Scaling tests provided evidence of non-allelic interaction in controlling most studied the genetic model was found to be adequate for explaining the inheritance of number of ears/plant in all crosses, ear diameter and number of rows/ear in the third cross as well as days to 50% silking in the first cross. The genetic model indicated that the additive, dominance and epistatis gene effects were significant for some earliness and yield characters among the three crosses. Additive and additive x additive gene effects were negative and significant for days to 50% tasselling and days to 50% silking in the third cross. The dominance and dominance x dominance gene effect were significant for days to 50% tasselling in second and third crosses crosses; and days to 50% silking and plant height in third cross. Duplicate type of epistasis was detected for some earliness and yield characters in all crosses. Complementary type of epistasis was also detected the first cross for number of grains/row.