The objective of this study was to investigate general and specific combining ability, degree of dominance (potence ratio). heterosis and inbreeding depression for yield and its components, in six parents diallel crosses. The bread wheat genotypes were three newly released cuitivars, Sakha 94, Gemmeiza 10 and Giza 1?0 and Line 5, Line 42, and Line 23. All traits exhibited predomination of non- additive gene action through low ratios of GCA f SCA except 100 kernel weight. The best two combiners were one of the newly released cultivars, (Gemmeiza 10) for grain yield, , number of spikes 1' plant, number of kernels l spike, 100 kernel weight, and plant height, and one promising line;(Line 5) for number of spikes f plant, 100 kernel weight and plant height. The best promising crosses to utilize non-additive gene action were five, i.e. PixPs, nP5, nP3, PaxPs and P4NP5 for grain yield f plant and at least one of yield components. Potence ratio showed different degrees of dominance in different directions, but averaged positively overdominance for all characters, except 100 kernel weight which gave negative average. Significantly positive heterosis were recorded for all the characters, ranging within (303-1809 % ) for tallness, ( 7.59- 64.09 % ) for number of spikes f plant, ( 6.19 - 25.23 % ) for number of kernels ! spike , (22.64 437.95 % ) for grain yield f plant, (41.30 - 114.63 % ) for total plant weight, and ( 15.41 % ) for 100 Kernel weight. The study could relate heterosis to non~additive gene effect as main effects or epistasis utilizing such effects. All these figures reflected the overdominance recorded for all the characters through potence ratio. On the other hand, all characters express considerable inbreeding depression in F2 population ranging within (7-18 %) for plant height, as compared to (14 - 4B % ), (13 - 39 % ), (14 -22 % ), ( 23 - 62 % ), and ( 22 54 %) for number of spikes, number of kernels, 100 kernel weight, plant grain yield and total plant weight, respectively.