Selection efficiency for grain yield under normal irrigation and water stress conditions in bread wheat

الملخص EN

The objective of the present research was to study the efficiency of pedigree selection for grain yield/plant under normal irrigation and water stress conditions.

Two cycles of pedigree selection for grain yield/plant were practiced separately under normal irrigation and water stress conditions.

The base population was the F3 population of Sids 1/Misr 1.

In the third year, selections under normal irrigation and water stress were evaluated at both environments.

The phenotypic was slightly larger than the genotypic variance, and generally decreased from the F3 to the F5 generation.

Broad-sense heritability was 87.08 and 85.38% under normal irrigation compared to 84.88 and 82.40% under water stress after cycle1 and 2, respectively.

The realized heritability was 40.08 and 67.40% under normal irrigation compared to 40.19 and 78.47% under water deficit after cycle1 and 2, respectively.

The average observed gains of normal irrigation selections were 19.58 and 23.66% from bulk sample and 7.93 and 8.73% from the better parent, while the average observed gains of water stress selections were 26.44 and 32.57% from bulk sample and 14.12 and 16.57% from the better parent, when evaluation practiced under normal irrigation and water stress, respectively.

The results indicated that the antagonistic selection was better than synergistic selection in changing the mean and decreased the sensitivity.

Grain yield/plant revealed positive and high phenotypic correlation with each of biological yield/plant, number of spikes/plant and number of kernels/spike under normal irrigation and water stress, and 100-kernel weight under water stress in the base population and after two cycle of selection for grain yield/plant.

The results of path-coefficient analysis revealed that number of spikes/plant had the highest positive direct effect on grain yield/plant followed by number of kernels/spikes and 100-kernel weight after two cycle of pedigree selection for grain yield/plant under normal irrigation and water stress conditions