Estimation of genetic parameters for yield and yield components in grain sorghum under drought stress conditions Heba M. Hafez, O.A.Y., Abd Elraheem and Y.M.Y. El kady Sorghum Research Department, Field Crop Research Institute, ARC, Egypt

This investigation was conducted at Shandaweel Research Station in the seasons from 2019, 2020 and 2021; to estimate some genetic parameters , using the six populations i.e. P1, P2, F1, F2, BC1 and BC2 of two grain sorghum crosses. P1, P2 and F1 were evaluated for drought tolerance under three levels of water deficit [100, 60 and 40% ET] in three separate experiments, with add F2, BC1 and BC2 under drought conditions [60 and 40% ET] in separate experiments. Results of analysis of variance indicated significant differences among the studied generations of each cross for studied traits. The genetic variances within F2 population were also found to be significant for all the studied traits in the two crosses, therefore genetic parameters were estimated. The scaling test values of A, B, C and D were significant for different studied traits. The positive and significant estimates for various types of gene action revealed that the dominance × dominance type of epistatic gene action, followed by the additive gene effect contributed by a large portion of the genetic components controlling the inheritance of the studied traits. Estimates of broad-sense heritability were high for all the study traits under 60 and 40% ET. In the same regard, under both conditions, the values of heritability in the narrow sense ranged from low to moderate in all investigated traits. The expected genetic advance as percentage of the F2 mean (Δg%) values were to selection for improving the studied traits in the segregating generations.