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Drought is a worldwide risk seriously influencing production of agricultural plants such as coriander. In order to evaluate heritability and gene action for important quantitative traits in coriander in three irrigation regimes, including well water (WW), mild water stress (MWS) and severe water stress (SWS), a cross between two genotypes of TN-59-158 (Sensitive parent) and TN-59-230 (Tolerant parent) was done. Parents and progenies of triple test cross were evaluated in filed condition through a randomized complete block design with three replications. Days to 50% flowering (DTF), days to harvest (DTH), fruit yield (FY), thousand fruit weight (TFW), harvest index (HI), relative water content (RWC), essential oil yield (EOY) were measured. Results showed that total epistasis effect was observed for all traits except RWC in WW. Also, total epistasis effect was observed for all traits except DTF in MWS and SWS. Partitioning of total epistasis revealed that [i] type of epistasis was contributed to determining DTF and TFW in WW and MWS treatments, DTH, FY and RWC in MWS and SWS treatments, and HI and EOY in WW, MWS and SWS treatments.