Quantitative genetic analysis of water deficit tolerance in coriander through physiological traits

Drought stress restricts the production of agricultural crops through morphological, physiological and biochemical changes in plants. This study explored the genetic control of physiological traits related to drought in coriander. In a diallel analysis, all six parents, their 15 F1hybrids and 15 F2populations were subjected to different irrigation regimes including well-watered, mild and severe water deficit stress. Drought stress decreased the relative chlorophyll content (RCC), the relative water content (RWC), chlorophyll a (Chla), chlorophyll b (Chlb), total chlorophyll (TChl) content, carotenoids (Car) and essential oil yield (EOY) in F1and F2generations. General combining ability (GCA) and specific combining ability effects were highly significant for all traits in F1and F2generations. Additive gene action was predominant for Chla, Chlb, TChl and Car under well-watered condition while non-additive gene effects were more important under mild and severe water deficit stresses in F1and F2generations for the above traits. Additive gene effects were more important for RCC, RWC and electrolyte leakage (EL) traits in both F1and F2generations under mild and severe water deficit stresses. In conclusion, the high narrow-sense heritability and significant genetic correlations between EOY and RCC, RWC and EL suggest that these traits can be used as surrogates to identify superior genotypes for arid and semi-arid regions. Also, the parental lines, P4and P6had the best GCA for RCC, RWC, Chla, Chlb, TChl, Car, essential oil content and EOY.