Effects of water stress on seed yield and essential oil content of dill genotypes
By: Kazem Ghassemi-Golezani, Limoo Rezaeipour, Saeideh Alizadeh-Salteh
Key Words: Dill, Essential oil, Genotype, Seed yield, Water stress.
J. Bio. Env. Sci. 9(1), 420-425, July 2016.
Water stress may alter essence content of medicinal plants. Thus, a split plot experiment based on RCB design with three replications was conducted in 2015, to evaluate the effects of different irrigation treatments (I1, I2, I3, I4: irrigation after 70, 100, 130 and 160 mm evaporation, respectively) on seed yield and essential oil content of three dill (Anethum graveolens L.) genotypes (Isfahan, Malayer, Varamin). Irrigation treatments and genotypes were allocated to the main and sub-plots, respectively. The essential oil of seeds was extracted by hydro distillation. Means of seeds per plant and seed weight were decreased due to water deficit, which led to significant reduction in seed yield per unit area under severe water stress. Although essential oil percentage of dill seeds increased with decreasing water availability, the highest essential oil yield per unit area was obtained under mild (I2) and moderate (I3) water stress. However, severe water deficit significantly reduced essence yield as a result of a large reduction in seed yield per unit area. Malayer with the greatest number of seeds per plant and Varamin with the largest seeds were the high yielding cultivars, with no significant difference in seed yield per unit area. Consequently, seed essence yield of Varamin and Malayer genotypes was about 25% higher than that of Isfahan genotype.