Comparison of biological yield, essential oil content and composition and phenological stages of moldavian balm (Dracocephalum moldavica L.) in three planting dates

In order to compare biological yield, essential oil content, composition and phonological stages of moldavian balm in three planting date seasons, a completely randomized design with three replications was conducted in 2006-2007 in Isfahan province. Biological yield per date and area unit, allocation index, percentage and yield of essential oil, dry matter to fresh matter ratio and essence components and period of sowing to flowering were measured. According to results, the majority of seedlings were injured in autumn planting date (November). Fresh and dry biological yields, essential oil quality per m2 of moldavian balm had significant differences and in spring (March) were 12.7 kg, 10.3cc and 4.1kg and in summer (June) were 4.1, 1 kg and 4.1cc, respectively. Essential oil quantity were significantly higher than summer sowing date (June). 46.7% and 62.2% fresh biological matter changed to dry matter in spring sowing date and summer sowing date, respectively. Sum of five major components (neral, geraniol, geranial, neryl acetate and geranyl acetate) in essence were 92% and 64.4% in spring and summer sowing date and maximum change was seen in geranyl acetate (from 35.3% in spring to 14% in summer). Growth periods from sowing to flowering stage were 122 and 61 days in spring and summer sowing date, respectively. Thus, summer sowing date is comparable with spring sowing date.