Phenology, Essential Oil Yield and Quality of Cumin (Cuminum cyminum L.) Affected by Sowing Dates and Plant Densities

Field experiments were conducted for evaluation of effects of sowing dates and plant densities on phenology and essential oil quality of cumin (Cuminum cyminum L.). The experiments were arranged as factorial based on randomized complete block design with sowing the dates of 26(th) March, 5(th), 15(th) and 25(th) April, and densities as 25.0, 31.3, 41.7 and 62.5 plants.m(-2). Results showed that the lowest growth period was on 25(th) April. Plants sown on 26(th) March had greater seed yield than those sown on later sowing dates. The earliest sowing date produced the largest seeds with a thousand seed weight of 3 g. The treatment of 26(th) March x 62.5 plants.m(-2) produced higher essential oil. Among tested independent variables, seed yield showed a significant effect on essential oil yield. Essential oil content improved 7.55 x 10(-3) mL.m(-2) per kg, increasing seed yield of cumin. Plant density did not show any considerable effect on the essential oil components of cumin. Delaying in sowing date caused a significan: effect on cuminaldehyde concentration in essence; thus, a maximum value was obtained from 26(th) March and 5(th) April sowings. For successful seed production and higher essential oil quantity and quality, cumin must be sown until late March (26(th) March) with density of 62.5 plants.m(-2) in Tabriz region.