Planting Date Effects on Growth, Seed Yield, Essential Oil Content and Chemical Composition of Ajowan

Abstract

In order to study the effects of planting date on seed yield, yield components and essential oil content and components of
ajowan, an experiment was carried out in the experimental field of Agriculture College of Shiraz University in 2007 year. The
experiments were conducted based on design randomized complete blocks with six treatment and four replications. Treatments
included six different planting date (in 30-day intervals from October to March). The essential oil was extracted by water distilled
method from seeds and it was analyzed by Gas Chromatography (GC). Measured traits in ajowan plants were significantly affected
by planting dates. By delay in planting date, plant height, number of branches per plant, number of umbels/plant, seed yield, 1000
seed weight, biologic yield and essential oil yield significantly were reduced. Highest of seed yield (650.1 kg/ha) was obtained from
October date and also planting date had significant effect on essential oil content and composition. Thymol is the main component
of oil. On the whole, the maximum thymol (61.85) of ajowan was obtained at the first planting date. The other major oil constituents
were γ-terpinene (27.35 %) p-cymene (11.79 %) and β-pinene (14.04 %). Ajowan plants can be successfully grown in the Fars
regions by early October as the best time for sowing.