Bread Wheat (Triticum aestivum L.) is one of the world’s major cereal crops and a stable food in many regions, grown under both irrigated and rain fed conditions. Currently Ethiopia is expanding wheat production to low altitude areas and off-season irrigated farming. Identification and development of high yielding and adaptive bread wheat genotypes for these created demand is a timely task. There for this research aims to identify high yielding genotypes and to estimate the genetic variability, heritability and genetic advance of yield determining traits of bread wheat genotypes. Sixty four bread wheat advanced pure lines and standard checks were evaluated using simple lattice (8X8) design in the central highland of Ethiopia, Ginchi, under irrigation condition. Analysis of variance result of all considered traits, except number of tillers per plant, showed highly significant differences (p<0.01). Mean grain yield production were ranged from 3763 kg ha-1 to 6811 kg ha-1, with overall population mean of 5561. Genotypes: G31, G11, G51, G6, G3, G34, G23, G5, G41, and G59 showed average grain production per hectare. The study revealed that there were considerable phenotypic and genotypic variations among tested genotypes. Traits: grain yield hector-1, biomass yield, number of kernels spike-1, and thousand kernels weight showed moderate phenotypic coefficients of variations. All traits exhibited low genotypic coefficients of variations, with the exception of grain yield, which had a moderate value. Broad sense heritability ranged from 30% for biomass yield to 91% for days to 50% heading. Expected genetic advance as percent of mean values were ranged from 3.73% for days to 50% emergency to 16.91% for thousand kernel weight. Moderate results of grain yield, harvest index, days to 50% heading, thousand kernels weight and number of kernels per spike on broad sense heritability and genetic advance as percent of mean indicate the use of these traits for direct selection would bring advancement. Hence, the current study was conducted only in one location and season, it needs additional location and season trial to confirm the findings and advance the promising genotypes to the next level of breeding program.

Keywords: Phenotypic variance, genotypic variance, heritability and genetic advance