Univrsity of Tehran Press Iranian Journal of Field Crop Science 2008-4811 52 3 2021 09 23 Quantitative and qualitative changes of ajowan (Carum copticum L. C.B. Clarke) essential oil in spring and summer cultivation under salinity stress Quantitative and qualitative changes of ajowan (Carum copticum L. C.B. Clarke) essential oil in spring and summer cultivation under salinity stress 251 260 84630 10.22059/ijfcs.2020.293886.654668 FA Saeid Davazdahemami Natural Resources Research Department, Isfahan Agricultural and Natural Resources Research Center, Agricultural Research Education and Extension Organization (AREEO), Isfahan, Iran. 0000-0003-2722-7494 Sohila Dokhani Agriculture Faculty, University of Khorasgan, Esfahan, Iran. Forogh Mortazanezhad Agriculture Faculty, University of Khorasgan, Esfahan, Iran. Marzyeh Allahdadi . Plant Ecophysiology Department, Agriculture Faculty, University of Tabriz, Iran Journal Article 2020 01 15 Ajowan<strong><em> </em></strong>(<em>Carum copticum </em>L. C.B. Clarke) is an annual plant of the Apiaceae family with medicinal, health and industrial uses. To investigate the effect of irrigation water salinity and planting date on some characteristics of this plant, a split-split plot experiment based on a randomized complete design with three replications was conducted in Isfahan, Iran. Two different planting dates (spring: March 23 and summer: June 21) and four different salinity levels (0.3 (control), 3, 6 and 9 dS/m), were assigned to main plots and subplots, respectively. The results showed that the highest plant height (93.2 cm) and biological yield (1367.7 g/m²) were obtained at 0.3 dS/m and summer planting date and maximum seed yield (230 g/m²) was observed at 0.3 dS/m and spring planting date. Increasing salinity levels decreased plant height, biological and seed yields. Interaction effects of salinity and planting season on essential oil percent and yield was not significant. The number of compounds identified in aerial parts of essential oil was 15 and 11 in summer and spring planting season, respectively. Based on the results, salinity had significant effect on essential oil yield, but no significant effect on essential oil percentage. Quality and quantity changes of essential oil components had no typical pattern. Spring was the most appropriate planting date in Isfahan climatic conditions for ajowan. Ajowan<strong><em> </em></strong>(<em>Carum copticum </em>L. C.B. Clarke) is an annual plant of the Apiaceae family with medicinal, health and industrial uses. To investigate the effect of irrigation water salinity and planting date on some characteristics of this plant, a split-split plot experiment based on a randomized complete design with three replications was conducted in Isfahan, Iran. Two different planting dates (spring: March 23 and summer: June 21) and four different salinity levels (0.3 (control), 3, 6 and 9 dS/m), were assigned to main plots and subplots, respectively. The results showed that the highest plant height (93.2 cm) and biological yield (1367.7 g/m²) were obtained at 0.3 dS/m and summer planting date and maximum seed yield (230 g/m²) was observed at 0.3 dS/m and spring planting date. Increasing salinity levels decreased plant height, biological and seed yields. Interaction effects of salinity and planting season on essential oil percent and yield was not significant. The number of compounds identified in aerial parts of essential oil was 15 and 11 in summer and spring planting season, respectively. Based on the results, salinity had significant effect on essential oil yield, but no significant effect on essential oil percentage. Quality and quantity changes of essential oil components had no typical pattern. Spring was the most appropriate planting date in Isfahan climatic conditions for ajowan. https://ijfcs.ut.ac.ir/article_84630_41c11bb2e7f3bea112f80d3c56aef51f.pdf