Estimation of genetic variability and frequency distribution in F2 generation of rice under normal and deficit water supply

Abstract

The investigation was conducted at the experimental farm of the Rice Research and Training Centre, Kafr el Sheikh, Egypt, during the summer seasons from 2017 to 2019 using the experimental material consisting two populations with their two parents (P1, P2, F1 and F2) to study the variability in the F2 population of four crosses: IR 78,936-B-B-B-B (water deficit tolerant) x Giza 177 (water deficit sensitive), FL-496 (moderately water deficit tolerant) x Giza 177, IR 78,936-B-B-B-B (water deficit tolerant) x Giza 178 (moderately water deficit tolerant), FL-496 × Giza 178 under normal (NWS) and deficit water supply (DWS). The experiment was conducted in a randomized complete block design with three replications. The results indicated that the phenotypic values of the measured characters were significantly different between the two parents of all the studied crosses under the two water supply conditions. The means of all the studied characters under DWS were lower than the means under NWS, but the yields and the yield components under DWS varied greatly among the parents due to stress. The averages of the measured traits of the F1 plants and the F2 populations in all crosses were near the averages of those of the parents. The results showed no consistent reduction in heritability under DWS compared to NWS. High heritability in a broad sense coupled with high genetic advance (GA) was observed for grain yield in Cross 1 under the two studied conditions offering good scope for selection.