This study was undertaken at the Experimental and Re-search Center, Faculty of Agriculture, at Moshtohor to estimate genetic variance components and their interaction with planting dates In the synthetic variety Cairo-i. Design ، mating scheme as suggested by Comstock and Robinson (1948) was applied by crossIng 28 males to different four females in 1992 season These entries weر evaluated in two dffferent planting dates in 1993 season The results could be summarized as follows: . - The additive genetic variance was the predominant component in the inheritance of most traits whereas dominance variance was negative and slgnijicant. . - Low to moderate heritability values in narrow sense were obtàined for grain yield/plant, ear length, and ear diameter. Whereas, high estima tion of h2 were obtainedfor plant height and sWUng date. - The expected genetic gain from selection was 830, 17.21, 172, 14.28, 21.94, 22.71, and 2Z 74 g/cycle for mass selection one .iex and two sexes. modf /led ear -to- row, hajjC sib selection, fr11- sib selection, test. cross, and Sj selection, respectively. The most effident scheme would1 be Si selection followed by test cross andfkll- sib family selection