In order to study the variations amongeset a half diallel cross using seven varieties for drought characters, estimating combining ability and genetic components. Two field experiments was carried out at the Experimental Farm of faculity of Agricultural- Tanta University during the two seasons 2016/2017 and 2017/2018, seven diverse wheat varieties (Triticum aestivum, L.) and 21 F1's were planted in two experiments. The first experiment was normally irrigated four times at different stages, the second one irrigated only once at tillering stage. The main results can be summarized as follow ; the water stress treatment decreased the means of flag leaf area (FLa), flag leaf angle (FLang), transpiration rate (TR), number of spikes/plant (NS/P), number of grains/spike (NK/S), 1000–grain weight (100-GW) and grain yield/plant (GY/P) for parents and their hybrids. The means of stomatal resistance (SR), chlorophyll a/b ratio (Chl a/b) and leaf temperature (LT) was increased under water stress. Irrigation mean squares were significant for all studied traits, indicating that the two irrigation regimes behaved differently for these characters. In addition, mean squares due to genotypes were highly significant for all traits except for FLA under  stress condition. Mean squares of combining ability were highly significant for almost of all the studied traits under the two environments and their combined,  indicating the presence of both additive and non additive types of gene effects in the genetic system controlling of these traits. The four parents Gemmeiza 12 (P1), Misr1(P2), Giza 171 (P3) and Giza 168 (P6) could be considered as excellent parents in breeding programs aimed to release parents to drought tolerance. The best parental combinations were ; Giza 168 (P6) x Gemmeiza 11 (P7), Giza171 (P3) x Giza 168 (P6), Giza 171 (P3) x Gemmeiza 11 (P7) and Gemmeiza 12 (P1) x Giza 168 (P6) for almost of the studied traits.