Identification of Suitable Parents for Essential Oil Yield in Coriander Half-sib Families under Different Environmental Conditions

Development of drought-tolerant cultivars with high essential oil yield is important for production of medicinal plants. So far application of half-sib mating has not been used in the coriander breeding for high essential oil yield and drought tolerance. In this study, 14 half-sib families of coriander derived from poly-cross design were evaluated under three irrigation treatments including: well water, mild water deficit stress and intense water deficit stress. In each environment, the half-sib families were evaluated using a randomized complete block design with three replications. Six drought-tolerance indices, including stress tolerance index (STI), geometric mean productivity (GMP), mean productivity (MP), harmonic mean (HM), stress tolerance (TOL) and stress susceptibility index (SSI) were calculated based on essential oil yield under non-stress (YP), mild stress (YM) and intense stress (YS). The results of correlation coefficients and biplot analysis revealed that STI, GMP, MP and HM indices could be effectively used for screening of drought tolerant genotypes of the coriander. Selection by these indices can be useful to identify a genotype with desirable essential oil yield in both non-stress and stress conditions. According to the results of three-dimensional graphs and view of biplot, half-sib families’ No. 6, 7 and 14 under mild stress and half-sib families’ No. 6, 7 and 12 under intense stress were selected as drought tolerant, and with high essential oil yield under non-stress and stress conditions. Therefore, these half-sib families can be used as a source of elite parents for synthetic cultivars in the coriander.