Eight local and exotic cultivars of rice were crossed to obtain 28 F1 crosses, through half diallel mating design. The eight parents and their 28 F1s ( excluding reciprocals) were grown in a randomized block design with three replications at the farm of Sakha Research Station, Sakha, Kafr El-Sheikh, Egypt in 2020 and 2021 rice seasons. GCA and SCA were significant for most of studied traits. GCA/SCA ratios were found to be less than unity for all studied traits, indicating that the non-additive type of gene action was great importance in the inheritance of these traits. Estimates of GCA effects indicated that, the parent IET1444 was a good general combiner for most of studied characters. The hybrid combinations IR 65600-77×Nerica 9 were the best SCA for most of studied characters. IR 65600-77×Nerica 9 rice hybrid exhibited significant and highly significant positive estimates of heterosis as a deviation from mid and better parent for root length, number of roots/plant, root volume, root/shoot ratio, relative water content, flag leaf area, number of panicles/plant, 1000-grain weight and grain yield/plant under water deficit conditions, except root length for better parent was insignificant.