Genetics and heritability of some physiological and agronomic traits in barley under drought stress

To evaluate the inheritance of some physiological and agronomic traits in barley, the F1 seeds of a 5×5 half diallel cross, along with their parents were grown in well-watered and drought stress under greenhouse condition at the agricultural research station of Islamic Azad University, Ardabil, Iran in 2016. Physiological and agronomic traits such as relative water content, excised leaf water loss, stomatal conductance, cell membrane injury, chlorophyll fluorescence parameters, specific leaf area, leaf thickness, root length, root dry weight and grain yield were measured. Results showed that all traits had high broad sense heritability. Among the traits, cell membrane injury had the highest narrow sense heritability (0.47), followed by specific leaf area (0.369), excised leaf water loss (0.353) and relative water content (0.311). The average degree of dominance was higher than unity for all traits, indicating the presence of over-dominance gene action in the control of these traits. Results showed that for grain yield and specific leaf area, dominant alleles, and for cell membrane injury, recessive alleles are favorable. F1 progenies had lower specific leaf area, excised leaf water loss, relative water content, stomatal conductance and higher root dry weight than their parents. Due to the importance of dominance in the control of characters under study, it was suggested that the evaluation of traits under study should be done at advanced generations of inbreeding.