Selection Efficiency for Grain Yield under Normal Irrigation and Water Stress
Conditions in grain sorghum (Sorghum bicolor L. Moench)

The present research aims to study the efficiency of pedigree selection for grain yield/plant under normal irrigation and water stress conditions. Breeding fields were conducted in Arab El-Awamer at Assuit gov. during 2019, 2020, and 2021 seasons. 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 (ZSV -14 and MR -812). In the third year, selection under normal irrigation and water stress were evaluated in both environments. The phenotypic variance was slightly larger than the genotypic one and generally decreased from the F3 to the F5 generation. Broad-sense heritability was 87.53 and 71.99 % under normal irrigation compared to 88.22 and 80.87% under water stress after cycle1 and 2, respectively. The average observed gains of normal irrigation selections were 39.2 and 36.59 % from the bulk sample and 20.84 and 18.12 % from the better parent, while the average observed gains of water stress selections were 27.81 and 31.96% from the bulk sample and 10.93 and 14.11% from the better parent, when evaluation practiced under normal irrigation and water stress, respectively. Grain yield/plant revealed a positive and high phenotypic correlation with the the1000-kernel weight under normal irrigation and water stress after two cycles of selection for grain yield/plant. The results of the path-coefficient analysis revealed that 1000-kernel weight had the highest positive direct effect on grain yield/plant followed by panicle width after two cycles of pedigree selection for grain yield/plant under normal irrigation and water stress conditions. two parents indicates over-dominance under normal irrigation, in which the population mean (53.01 g) outyielded the higher yielding parent, ZSV-14 (48.93 g) and tended to show complete dominance (47.51 g) towards the higher parent ZSV-14 (44.60 g) under water stress. The reduction caused by water stress in the F 3 families was 1.775, -0.747, 9.091, 14.94, 19.02 and10.38 % for Plant height, days to 50% flowering, panicle length, panicle width, 1000-kernel weight, and grain yield /plant, respectively. These results are in harmony with those obtained by Chigwe (1984), Al-Naggar et al. (1999), Mahdy et al. (2000), Ali (2002), Amir (2004), Amir (2008), Mohamed (2012), Mahmoud et al. (2013), Soliman et al. (2015) and Tag El-din (2015). The phenotypic (P.C.V. %) and genotypic (G.C.V. %) coefficient of variations were sufficient for selection in the base population and ranged from (4.82 – 16.89 %) and (4.57– 15.87%) under normal irrigation, and from (4.54–18.79 %) and (4.33 – 16.27 %) under water stress; for days to 50% flowering, panicle length and 1000- kernel weight, respectively. These results indicate that selection among F 3 families for grain yield could be effective. These findings are in line with those reported by Ali (2002), Kenga et al. (2006), El-Morshidy et al. (2010), Ali et al. (2012), Ali (2012), Ali et al. (2007), Abd-El-Haleem et al. (2012), Mahdy (2012) and Hassaballa