Effects of Cultivation Methods on Yield and Essential Oils of Chrysanthemum indicum L. (Gamgug)

Chrysanthemum indicum L. (Gamgug) has been examined to study their flowering habits, yields and bioactive compounds under different planting densities and mowing dates. The planting density experiment revealed a significantly increasing stem diameter, number of flowers and branches with decreasing plant density in the $100\;cm{\times}30\;cm$ and $130\;cm{\times}30\;cm$ treatments as compared to $70\;cm{\times}30\;cm$ treatments, but not plant height, leaf and flower width. On the other hand, the mowing date experiment showed that growth characteristics of plants were similar to the control plants (not mowing) and June 20 treatment, but July 20 treatments had significantly smaller than the control. The weights (g $plant^{-1}$) of dry flowers were affected by the planting density and mowing date. The flower yield of $586\;kg\;ha^{-1}$ obtained at $100\;cm{\times}30\;cm$ density was 11% and 22% higher than that of $120\;cm{\times}30\;cm$ and $70\;cm{\times}30\;cm$ treatments, respectively. The yield of dry flowers in the control and June 20 mowing date ranged $495-508\;kg\;ha^{-1}$, which is 40-42% higher than the yield in the July 20 treatments. The amount of essential oil (g $plant^{-1}$) in medically valuable flowerheads of C. indicum L. was statistically different between mowing dates but not among planting densities. The study showed that planting density and the mowing date could increase yields of flowerheads. An optimum planting density of $100\;cm{\times}30\;cm$ and mowing date of on or before June 20 is recommended for C. indicum L.