To estimate the efficiency of single trait selection for days to heading in the F₄, F₅ and F₆-generations of population (Giza 168 × Sids 4) (Triticum aestivum L.) two experiments conducted under normal irrigation and drought stressed environments. Mean squares in F₄ and F₆-generations of all the studied traits were significant (p<0.01) for the selected families to days to heading under both environments. The pcv and gcv % tended to be low under the two environments and close to each other, which resulted in high estimates of  broad sense heritability; 98.49 and 98.06 and high estimates of expected genetic advance of 11.72 and 10.27% of the F₄-mean under normal and stressed environments; respectively. After two cycle of pedigree selection for days to heading the gcv and pcv was 6.03 and 6.15 compared to 6.42 and 6.47% in the F₄ under irrigation, and was 4.46 and 4.61 compared to 5.63 and 5.69% in the F₄-generation under drought stress; respectively. The average direct gain was significant (p<0.01) and reached -16.36 and -10.17% from the bulk sample under normal irrigation and drought stress environments; respectively. Average direct gain in percentage of the earlier parent Sids4 was significant (p<0.05) under normal irrigation (-2.55%), but, insignificant (-1.39%) under drought stress. On the level if individual families four families (No.44, No.48, No.68 and No.147) showed significant (p<0.01) earliness than the earlier parent Sids4 under normal irrigation. However, under drought stress two families out of ten (No.63 and No.147) showed significant (p<0.05) earliness from Sids4 and showed significant observed gain in grain yield/plant from the better parent, and could be considered the best families. These results indicate that selection for earliness was more effective under normal irrigation than under drought stress in detecting the early family. The genotypic correlation of DH with GY/P was very weak in both of the F₄ and F₆-generations, but, changed from 0.02 to -0.09. Meaning that early families slight increased grain yield/plant under normal irrigation.