Effect of 11 essential oils on seed germination, radicle development, and seedling growth in wheat and barley

Authors: ALJAYAN, LULUH - Oregon State University; ASTATKIE, TESS - Dalhousie University; ERICKSON, STEPHEN - Oregon State University; Cantrell, Charles; ZHELJAZKOV, VALTCHO - Oregon State University

Submitted to: Journal of Agriculture and Food Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/21/2025
Publication Date: 4/22/2025
Citation: Aljayan, L.N., Astatkie, T., Erickson, S., Cantrell, C.L., Zheljazkov, V.D. 2025. Effect of 11 essential oils on seed germination, radicle development, and seedling growth in wheat and barley. Journal of Agriculture and Food Research. 21(2025):1019444. https://doi.org/10.1016/j.jafr.2025.101944.
DOI: https://doi.org/10.1016/j.jafr.2025.101944

Interpretive Summary: Wheat and barley are the two most important small-grain crops globally. A persistent challenge in their cultivation is pre-harvest sprouting (PHS), which occurs when seeds begin to germinate on the spike due to rainfall before harvest. This study hypothesized that essential oils could suppress seed germination in wheat and barley, offering a potential avenue for developing products to mitigate PHS. Accordingly, the objective was to evaluate the effects of 11 essential oils (EOs) (Eucalyptus polybractea) (blue mallee), Eucalyptus globulus, Cinnamomum cassia, Abies sabirinensis (fir needle), Artemisia vulgaris (mugwort), Citrus paradisi (grapefruit), Commiphora myrrha (myrrh), Melaleuca qui viridiflora (Niaouli), Pinus strobus (white pine), Citrus reticulata (tangerine), and Cymbopogon martini (palmarosa) on germination rate (%), number of seminal roots, root length (mm), and seedling height (mm) of two types of grain crops: wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.). Barley and wheat seed germination was suppressed by applying Cymbopogon martini and Cinnamomum cassia EOs at 1, 3 and 9 µL; these EO significantly decreased all response variables relative to the non-treated control. More research is necessary to confirm the findings in field conditions. This study suggests that Cymbopogon martini and Cinnamomum cassia EO can potentially be utilized for controlling PHS in wheat and barley.

Technical Abstract: Wheat and barley are the two most important small-grain crops globally. A persistent challenge in their cultivation is pre-harvest sprouting (PHS), which occurs when seeds begin to germinate on the spike due to rainfall before harvest. This study hypothesized that essential oils could suppress seed germination in wheat and barley, offering a potential avenue for developing products to mitigate PHS. Accordingly, the objective was to evaluate the effects of 11 essential oils (EOs) (Eucalyptus polybractea) (blue mallee), Eucalyptus globulus, Cinnamomum cassia, Abies sabirinensis (fir needle), Artemisia vulgaris (mugwort), Citrus paradisi (grapefruit), Commiphora myrrha (myrrh), Melaleuca qui viridiflora (Niaouli), Pinus strobus (white pine), Citrus reticulata (tangerine), and Cymbopogon martini (palmarosa) on germination rate (%), number of seminal roots, root length (mm), and seedling height (mm) of two types of grain crops: wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.). Essential oils were applied at rates of (0, 10, 30, and 90 µL/Petri dish) to study their inhibitory effect on seeds. The application of Cymbopogon martini and Cinnamomum cassia EOs reduced wheat and barley seed germination rate (%), number of seminal roots, root length (mm), and seedling height (mm) at 10 µL. Therefore, they were further evaluated at reduced amounts (0, 1, 3, and 9 µL/Petri dish). Barley and wheat seed germination was suppressed by applying Cymbopogon martini and Cinnamomum cassia EOs at 1, 3 and 9 µL; these EO significantly decreased all response variables relative to the non-treated control. Due to the effectiveness of the EOs, even at low amounts, a tetrazolium test (TZ) was conducted to test the viability of the seeds after they were exposed to EOs. The results of the TZ test showed that EOs had significant effects on seed viability. When the amount of EOs increased, the viability of the seed decreased. More research is necessary to confirm the findings in field conditions. This study suggests that Cymbopogon martini and Cinnamomum cassia EO can potentially be utilized for controlling PHS in wheat and barley.