World Journal of Agricultural Research. 2014, 2(2), 56-62DOI:
Abstract: Field experiments were carried out at Faculty of Agriculture, Sohag University, Egypt to estimate observed and expected response to selection and genetic parameters after two cycles of phenotypic selection in F2 population. Highly significant differences among F3 and F4 families under normal and drought stress conditions for no. of spikes/plant (NS), 100-Seed weight (SW), plant height (PH), days to heading (DH) and grain yield/plant (GY) were observed. Direct response to selection for NS, SW and PH were positive and highly significant with values of 15.16, 26.34 and 6.18 %, respectively compared with check cultivar ( 1) in F4 generation under normal conditions. Meanwhile, under drought conditions, they were 14.39, 20.35 and 6.35%, respectively. Correlated response to selection was significant and positive for GY compared with check cultivar under two conditions. While, it was very significant and negative for HD under normal and drought stress. Expected response to selection for NS, SW and PH were (1.45 and 1.62 spikes/plant), (0.37 and 0.23 gm) and (6.21 and 5.90 cm), respectively in F4 under normal and water stress conditions, respectively. High broad sense heritability values for NS, SW and PH was obtained under normal and drought stress in F3 and F4 generations. Narrow sense heritability in F4 were (48.24 and 55.31%), (53.34 and 43.43%) and (52.12 and 48.73%) for NS, SW and PH, respectively, under normal and drought stress, respectively. Positive and significant correlation between three characters (no. of spikes/pant, 100 kernel weight and plant height) and grain yield/plant under normal and drought stress conditions. Thus, direct selection of these characters should be of major concern for increased grain yield under two conditions. Drought susceptibility index (DSI) showed that four families were superior for drought tolerance and had high grain yield under drought stress in F4 generations. These genotypes could be used as source of drought tolerance/or factors contributing to general adaptation.