Forty-five F₁s of ten parent diallel cross (without reciprocals and parents) was planted in Karaj and Kerman, in a randomized complete block design with three replications in 1998. Combined analysis for two locations was done for grain yield, days to flowering, number of kernel rows, number of kernel/row, 1000 kernel weight, kernel depth, anthesis-silking interval (ASI), plant and ear height according to Griffing's method 4 (model B, 1956). General combining ability (GCA) effects were significant at 1% probability level for all traits except ASI, whereas, specific combining ability (SCA) effects were significant only for grain yield and plant height at 1% level and for number of kernel rows and kernel depth at 5% level. Thus, both additive and non-additive effects were found to be important in genetical control of grain yield, plant height, number of kernel rows and kernel depth and only additive effects in controlling days to flowering, ear height, number of kernel/row and 1000 kernel weight. Concerning the GCA effects of lines and role of additive effects in genetical control of traits, B73 and K17/2-5 inbred lines were determined as the useful sources for increasing grain yield and ear height, K1264/1, K722 and K1263/8 for production of early maturity germplasms and MO17 for increasing number of kernel/row and 1000 kernel weight.