Impact of Foliar-Applied Essential Oils on Growth, Yield and Quality of Potato (Solanum tuberosum L.)

In this study, effects of sage (Salvia officinalis L.), oregano (Origanum onites L.), rosemary (Rosmarinus officinalis L.), dill (Anethum graveolens L.), cumin (Cuminum cyminum L.), fennel (Foeniculum vulgare var. dulce L.) and Turkish pickling herb (Echinophora tenuifolia L. subsp. sibthorpiana (Guss.)) essential oils applied to plant leaves at different doses on potato growth, tuber yield and quality were investigated. Essential oils were applied to the upper parts of the plant by spraying at doses of 300, 600, 900 and 1200 ppm three times at 15-day intervals, starting 15 days after the completion of emergence. The number of tubers and tuber yield per plant, marketable and total tuber yield, chlorophyll content, starch content, reducing and total sugar content parameters were examined. The effects of essential oil applications on tuber yield and quality were found to be statistically significant, and this effect varied according to application doses. Compared to the control, essential oil applications increased the marketable tuber yield by approximately 38% (300 ppm rosemary essential oil) and the total tuber yield by up to 28% (600 ppm rosemary essential oil). However, rosemary and oregano oils caused phytotoxicity and reduced tuber yield when applied in high doses. Except for sage and oregano, other essential oils positively affected chlorophyll synthesis. Essential oil applications reduced the accumulation of reducing sugar, which negatively affects tuber quality, and the lowest reducing sugar contents were detected in tubers to which fennel and oregano essential oils were applied. In the study, it was understood that tuber yield in potatoes could be increased significantly with the applications of 300 and 600 ppm rosemary essential oil and 300 ppm cumin essential oil.