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This investigation was carried out at the Experimental Farm of Gemmeiza Agriculture Research Station, Egyptduring the three successive seasons,i.e., 2015/2016, 2016/2017 and 2017/2018 to study nature of gene action for yield andits components, heterosis expression, heritability and expected genetic advance under normal and water stress conditions.Six populations model (P1, P2, F1, F2, BC1 and BC2) was used in this study for three crosses; (I) Gemmeiza 11× Giza168, (II) Giza 171× Shandawel 1 and (III) Gemmeiza 9× Misr1. Means of the six generations were recorded for eightcharacters, i.e. number of spikes per plant, plant height, main spike length, number of spikelets per main spike, number ofkernels per main spike, main spike yield, grain yield per plant and 1000- kernels weight. Results revealed that thecoincidence of sign and magnitude of heterosis and inbreeding depression was also detected for most characters in thethree crosses under both conditions. Study of generation means analysis revealed that additive, dominance and epistasiceffects were involved in the inheritance of yield and its components. Additive (a) and dominance (d) genes effects weresignificant for most studied characters under both conditions. High heritability estimates in broad sense were detected forall studied characters in the three crosses under both conditions, except, main spike yield in the first cross under stress.Narrow sense heritability estimates were found to be high for most characters under both conditions. Moderate to highgenetic advance (Δg%) was detected for all characters of the three crosses under the two environments, except, plantheight for the three crosses under normal condition and first and second cross under stress condition. The highestestimates of narrow sense heritability associated with highest genetic advance for most of the studied characters in most ofcrosses under both conditions indicated sufficient improvement of the variable characters. These results indicated thepossibility of practicing selection in early generations for these characters. |
