Six bread wheat cultivars/lines viz., Faisalabad-08, Lasani-08, Sehar-06, Chakwal-86, Chakwal-50 and 6302 were hybridized in full diallel fashion. Thirty F1 crosses along with six parents were planted in a triplicate randomized complete block design in the experimental area of Department of Plant Breeding and Genetics, University of Agriculture, Faisalabad. Experiment was sown under both normal and drought conditions. Data on attributes viz., plant height, flag leaf area, number of tillers per plant, number of spikelets per spike, number of grains per spike, 1000-grain weight, spike length, spike density, grain weight per spike, biomass per plant, grain yield per plant, harvest index, extrusion length, stomatal frequency, stomata size, epidermal cell size and leaf venations were recorded and subjected to the analysis of variance technique to find out the genotypic differences for the characters, which were found significant under both environmental conditions. Data were further subjected to diallel analysis for genetic studies. The Vr-Wr graphs indicated over-dominance type of gene action for spike length and grain weight per spike and leaf venations under both sowing conditions and for flag leaf area, biomass per plant, harvest index and stomatal frequency under normal condition, whereas for number of tillers per plant under drought condition. Additive with partial dominance type of gene action was observed for number of spikelets per spike, number of grains per spike, plant height, 1000-gran weight, grain yield per plant, extrusion length, spike density, stomata size and epidermal cell size under both sowing conditions and for number of tillers per plant under normal condition and for biomass per plant, harvest index, stomatal frequency and flag leaf area under drought condition. Over-dominance type of gene action detected under normal condition for flag leaf area, biomass per plant, harvest index, and stomatal frequency was changed to additive with partial dominance type of gene action under drought condition, while additive with partial dominance gene action under normal condition for number of tillers per plant was altered to over-dominance type of gene action under drought condition