The present investigation was carried out at the Experimental Farm of Etai El-Baroud Agricultural Research Station, El-Beheira Governorate (Agricultural Research Center) during the two successive seasons of 2016-2017 and 2017-2018. Eight bread wheat cultivars and lines representing a wide range of diversity for several agronomic characters were selected for the study in a half diallel mating design which were analyzed by using Griffing's method and GGE biplot graph. The genetic analysis (variance, combining ability, heterosis, and Biplot) of grain yield per plant and some agronomic traits were evaluated. Genotypes were randomly distributed using RCBD design with three replications. Results revealed highly significant variations within parents and F1 genotypes indicating a wide genetic variability for the studied characters and the possibility of genetic improvement using such genetic pools of wheat. Both general (GCA) and specific (SCA) combining abilities were significant for all studied characters revealing the important role of both additive and dominant components in the inheritance of the studied characters. Gemmeiza9 was good general combiner for grain yield/plant, biological yield, spike length, number of spikes per plant, number of kernels per spike and chlorophyll content. Several crosses exhibited highly significantly positive SCA effects for studied characters especially Gemmeiza9 × Line2 for grain yield/plant and most attributes. Highly significant heterosis was detected in two crosses (Gemmeiza9 x Line2) and (Sids13 x Line2) for grain yield/plant and some agronomic traits. Biplot graph is considered quickly and effective tool for assessing the genetic interrelationship among the genotypes.