This research was conducted to screen and analyse the variability within twenty F 3 populations of bread wheat (Triticum aestivum L.) generated by Line x Tester mating design.The results indicated the presence of sufficient variability within and between F 3 populations for the eight measured variables, which represent plant phenology, physiology, yield and yield components. Different populations have been identified to improve the measured variables separately. The number of spikes appeared to be the most important determinant of grain yield.PCA and cluster analyses indicated that the Acsad 1069 /El Wifak and Acsad 1135 /Hidhab, with a relatively high grain yield, aboveground biomass and 1000 grains weight, are the best F 3 populations to improve the productivity. However, Acsad 899 /Rmada and Acsad 1135 /Rmada populations were earlier and had a low number of spikes. These populations had also favorable genes for heat tolerance. Keywords ABSTRACTThis research was conducted to screen and analyse the variability within twenty F 3 populations of bread wheat (Triticum aestivum L.) generated by Line x Tester mating design.The results indicated the presence of sufficient variability within and between F 3 populations for the eight measured variables, which represent plant phenology, physiology, yield and yield components. Different populations have been identified to improve the measured variables separately. The number of spikes appeared to be the most important determinant of grain yield.PCA and cluster analyses indicated that the Acsad 1069 /El Wifak and Acsad 1135 /Hidhab, with a relatively high grain yield, aboveground biomass and 1000 grains weight, are the best F 3 populations to improve the productivity. However, Acsad 899 /Rmada and Acsad 1135 /Rmada populations were earlier and had a low number of spikes. These populations had also favorable genes for heat tolerance.