Selection for Grain Yield in Bread Wheat (Triticum aestivum L.) under Normal Irrigation and Water Stress Conditions

Abstract

The present research was carried out through the three successive seasons from 2016/17 to 2018/19 at Shandaweel Agric. Res. Stat., Sohag Governorate, Egypt, to study the efficiency of pedigree selection in improving grain yield in bread wheat under normal and drought conditions. Two cycles of selection were completed under each condition for F2 to F4-generations. At the last season, the selected F4 families under each condition were evaluated under both conditions. The genotypic variance was slightly less than the phenotypic variance under both conditions and generally decreased from the base population (F2) to F4-generation. Broad-sense heritability was 78.33 and 71.93% under normal irrigation compared to 86.44 and 58.48% under water stress after cycle1 and 2, respectively. The realized heritability was 29.93 and 90.88% under normal irrigation compared to 36.47 and 89.48% under water deficit after cycle1 and 2, respectively. The average observed gains of normal irrigation selections were 40.29 and 66.34% from bulk sample and 29.92 and 35.27% from the better parent, while the average observed gains of water stress selections were 32.89 and 40.42% from bulk sample and 23.07 and 14.19% from the better parent, when evaluation practiced under normal irrigation and water stress, respectively. The results indicated that the synergistic selection was better than antagonistic selection in changing the mean and decreased the sensitivity