Genetic analysis of physiological traits in bread wheat under normal and terminal water-deficit stress conditions

Estimation of the physiological responses in bread wheat helps to identify the effective mechanisms to improve yield production in adverse environmental conditions such as water-deficit stress. In this study, the inheritance of physiological traits and grain yield in two populations, namely “Parsi” × “Winter B. C. of Roshan” and “Sistan” × “Winter B. C. of Roshan” were investigated under two normal conditions and terminal water-deficit stress using the Generation Mean Analysis (GMA). The results of this experiment showed that grain yield decreased in both of crosses due to water-deficit stress, so that the average of grain yield decreased in “Parsi” × “Winter B. C. of Roshan”, from 12.66 g/plant to 10.03 g/plant, and in the second cross decreased from 12.93 g/plant to 9.68 g / plant. In normal condition of both crosses, the highest amount of narrow-sense heritabilityሺ݄௡ ଶሻ belonged to chlorophyll b content (52% -53%), leaf area index (50-58%) and total chlorophyll content (45-63%), respectively. In waterdeficit stress condition for the first population, the highest amount of narrow-sense heritability ሺ݄௡ ଶሻ belonged to the content of chlorophyll b (61%), leaf area (54%) and total chlorophyll content (68%), and in the second cross it belonged to content of chlorophyll a (78%) and leaf area (56%). The high amount of narrow-sense heritability for these traits illustrates that additive effects play a big role to control them. So, selection method could be effective method to improve the mentioned traits.

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