Document Type : Research Paper


1 Assistant Professor, Department of Horticultural Science, Faculty of Agriculture, University of Maragheh, Maragheh, Iran.

2 Assistant Professor, Crop and Horticultural Science Research Department, Kermanshah Agricultural and Natural Resources Research and Education Center, AREEO, Kermanshah, Iran.

3 Expert, Horticultural sector, Ministry of Markazi Province Jihad-e-Agriculture, Khondab, Iran.

4 Former M.Sc. Student, Department of Plant Protection, Faculty of Agriculture, University of Kurdistan, Sanandaj, Iran.


Sunburn is one of the important factors, limiting pomegranate production, especially in regions with hot summers. Since exogenous application of kaolin can increase tolerance to some environmental stresses by improving metabolic pathways and increasing net photosynthesis, this paper studies the effect of kaolin spraying on some pomological and biochemical characteristics of commercial pomegranate cultivars in Rijab region (Kermanshah province). Accordingly, it carries out a factorial experiment, based on a RCBD, which is consisted of three concentrations of kaolin (i.e., 0 (distilled water), 3%, and 6%) as well as two pomegranate cultivars (Malas Torsh & Yosef-Khani) with three replications. Results show that in both cultivars, kaolin treatment at 6% concentration improves fruit weight, the length and width of aril and fruit, aril weight, and the yield. In addition, fruits of both pomegranate trees with kaolin treatment at both concentrations, especially at 6% concentration, show increased soluble solids, fruit juice, and total phenol content. Despite the different morphological and biochemical reactions in the two cultivars, one of the cultivars could be used in accordance to different purposes and conditions. In addition, a high concentration of kaolin reduces sunburn and cracking of pomegranate fruits in both cultivars, increasing yield per hectare. This treatment can serve as a suitable method to reduce physiological disorders in pomegranate growing areas such as Rijab region.


Abd El-Rhman, I. E. (2010). Physiological studies on cracking phenomena of Pomegranates. Journal of Applied Sciences Research, 6(6), 696-703.
Abou El-Wafa, M. (2015). Effect of some treatments on reducing sunburn in wonderful pomegranate fruit trees. Egypt Journal of Horticulture, 42(2), 795-806. DOI: 10.21608/ejoh.2015.1332.
Aly, M., El-Megeed, N. A., & Awad, R. M. (2010). Reflective particle films affected on, sunburn, yield, mineral composition and fruit maturity of ‘Anna’ apple (Malus domestica) trees. Research Journal of Agriculture and Biological Sciences, 6, 84-92.
AOAC, Association Official Analytical Chemists. (2005). Official methods of analysis. 18th edn. Washington. DC. USA.
Denaxa, N. K., Roussos, P. A., Damvakaris, T., & Stournaras, V. (2012). Comparative effects of exogenous glycine betaine, kaolin clay particles and Ambiol on photosynthesis, leaf sclerophylly indexes and heat load of olive cv. Chondrolia Chalkidikis under drought. Scientia Horticulturae, 137, 87-94. DOI: 10.1016/j.scienta.2012.01.012.
Dinis, L. T., Bernardo, S., Conde, A., Pimentel, D., Ferreira, H., Felix, L., Geros, H., Correia, C. M., & Moutinho-Pereira, J. (2016). Kaolin exogenous application boosts antioxidant capacity and phenolic content in berries and leaves of grapevine under summer stress. Journal of Plant Physiology, 191, 45–53. DOI: 10.1016/j.jplph.2015.12.005.
Dinis, L. T., Malheiro, A. C., Luzio, A., Fraga, H., Ferreira, H., Gonçalves I., Pinto G., Correia C. M., & Moutinho-Pereira, J. (2018). Improvement of grapevine physiology and yield under summer stress by kaolin-foliar application: water relations, photosynthesis and oxidative damage. Photosynthetica, 56, 641. DOI: 10.1007/s11099-017-0714-3.
Faissal, F. A., Mokhtar, M. S., & Ahmed, M. K. (2011). Protecting crimson seedless grapevines growing in hot climates from sunburn. Research Journal of Agriculture and Biological Sciences, 7 (1), 135-141.
FAO. (2017). FAO Land and plant nutrition management service. http:/
Farazmand, H. (2012). Effect of processed kaolin on sunburn on pomegranate fruits. Pests and plant diseases, 80(2), 173- 184. (In Persian).
Fawole, O. A., & Opara, L. U. (2013). Changes in physical properties, chemical and elemental composition and antioxidant capacity of pomegranate (cv. Ruby) fruit at five maturity stages. Scientia Horticulturae, 150, 37–46. DOI: 10.1016/j.scienta.2012.10.026.
Ghanbarpour, E., Rezaei, M., & Lawson, S. (2019). Reduction of cracking in pomegranate fruit after foliar application of humic acid, calcium-boron and kaolin during water stress. Erwerbs-Obstbau, 61, 29. DOI: 10.1007/s10341-018-0386-6.
Giusti, M. M., & Wrolstad, R. E. (2001). Characterization and measurement of anthocyanins by UV–visible spectroscopy. In: Wrolstad, R. E., & Schwartz, S. J. (Eds.), Current protocols in food analytical chemistry, John Wiley and Sons, New York.
Glenn, D. M. (2010). Canopy gas exchange and water use efficiency of 'Empire' apple in response to particle film, irrigation, and microclimatic factors. Journal of the American Society for Horticultural Science, 135(1), 25–32. DOI: 10.21273/JASHS.135.1.25.
Glenn, D. M., Prado, E., Erez, A., McFerson, J., & Puterka, G. J. (2002). A reflective, processed kaolin particle film affects fruit temperature, radiation reflection, and solar injury in apple. Journal of the American Society for Horticultural Science, 127(2), 188-193. DOI: 10.21273/JASHS.127.2.188.
Hegazi, A., Samra, N. R., El-Baz, E. E. T., Bahan Khalil, M., & Gawish, M. S. (2014). Improving fruit quality of manfaloty and wonderfull pomegranates by using bagging and some spray treatments with gibberellic acid, calcium chloride and kaolin. Journal of Plant Production, 5(5), 779-792. DOI: 10.21608/jpp.2014.55421.
Hmid, I., Elothmani, D., Hanine, H., Oukabli, A., & Mehinagic, E. (2017). Comparative study of phenolic compounds and their antioxidant attributes of eighteen pomegranate (Punica granatum L.) cultivars grown in Morocco- Review. Arabian Journal of Chemistry, 10(2), 2675-2684. DOI: 10.1016/j.arabjc.2013.10.011.
Jalili Moghaddam, Z. (2015). Comprehensive pomegranate guide. Agricultural Education and Promotion Press. Tehran, Iran. pp. 22-72. (In Persian)
Kavand, M., Arzani, K., Barzegar, M., & Mirlatifi, M. (2016). Effects of sunscreen, kaolin application, fruit thinning and supplementary irrigation on the aril browning disorder of Pomegranate cv. “Malase Torshe Saveh”. Journal of seed and seedling Improvement, 33(1), 85-112. (In Persian). DOI: 10.22092/SPPJ.2017.113760.
Lal, N., & Sahu, N. (2017). Management strategies of sunburn in fruit crops-A Review. International Journal of Current Microbiology and Applied Sciences, 6(6), 1126-1138. DOI: 10.20546/ijcmas.2017.606.131.
Meighani, H Ghasemnezhad M, & Bakhshi D. (2015). Effect of kaolin on the sunburn damage and qualitative characteristics of pomegranate fruit cv. Malas-e-Torsh-e-Saveh. Iranian Journal of Horticultural Science (IJHS), 47(3), 491-499. (In Persian) 
Melgarejo, P., Martínez, J. J., Hernández, F. A., Martínez –Font, R., Barrows, P., & Erez, A. (2004). Kaolin treatment to reduce pomegranate sunburn. Scientia Horticulture, 100, 349-353. DOI: 10.1016/j.scienta.2003.09.006.
Mousavinejad, G., Emam-Djomeh, Z., Rezaei, K., & Khodaparast, M.H.H. (2009). Identification and quantification of phenolic compounds and their effects on antioxidant activity in pomegranate juices of eight Iranian cultivars. Food Chemistry, 115, 1274-79. DOI: 10.1016/j.foodchem.2009.01.044.
Parashar, A., & Ansari, A. (2012). A therapy to protect pomegranate (Punica granatum L.) from sunburn. International Journal of Comprehensive Pharmacy, 3, 1-3.
Rosati, A. (2007). Physiological effects of kaolin particle film technology: A review. Functional Plant Science, & Biotechnology, 1, 100-105.
Rosati, A., Metcalf, S., Buchner, R., Fulton, A., & Lampinen, B. (2007). Effects of kaolin application on light adsorption and distribution, radiation use efficiency and photosynthesis of almond and walnut canopies. Annals of Botany, 99(2), 255-263. DOI: 10.1093/aob/mcl252.
Roshan, A. A. (2007). Evaluation of agro-climatic zones compatible with olive (Olea europaea L.) cultivation in Iran. PhD. Thesis. University of Tehran.  Faculty of Geography. (In Persian).
Samra, B. N., & Shalan, A. M. (2013). Studies on thinning, bagging and aluminum silicate spraying on yield and quality of Wonderfull pomegranate. Journal of Plant Production, 4 (2), 219-227. DOI: 10.21608/jpp.2013.68984.
Sharma, R. R., Reddy, S. V. R., & Datta, S. C. (2015). Particle films and their applications in horticultural crops. Applied Clay Science, 116-117, 54-68. DOI: 10.1016/j.clay.2015.08.009.
Sharma, R. R., Datta, S. C., & Varghese, E. (2018). Effect of Surround WP®, a kaolin-based particle film on sunburn, fruit cracking and postharvest quality of ‘Kandhari’ pomegranates. Crop Protection, 114, 18-22. DOI: 10.1016/j.cropro.2018.08.009.
Singh, A., Burman, U., Saxena, A., & Meghwal, P. R. (2019). Interactive effects of micronutrients, kaolin and mulching under drip irrigation system in managing fruit cracking of pomegranate (Punica granatum). Acta Horticulturae, 1254, 213-218. DOI: 10.17660/ActaHortic.2019.1254.32.
Singleton, V. L., & Rossi, J. A. (1965). Colorimetry of total phenolics with phosphomolybdic-phosphotungstic acid reagents. American Journal of Enology and Viticulture, 16, 144-158.
Viyar, A. H., Qadri, R., Iqbal, A., Nisar, N., Khan, I., Bashir, M., & Shah, F. (2017). Evaluation of unexplored pomegranate cultivars for physicochemical characteristics and antioxidant activity. Journal of Food Science and Technology, 54(9), 2973-2979. DOI: 10.1007/s13197-017-2736-z.
Weerakkody, P., Jobling, J., Vergara, M. M., & Rogers, G. (2010). The effect of maturity, sunburn and the application of sunscreens on the internal and external qualities of pomegranate fruit grown in Australi. Scientia Horticulturae, 124 (1), 57–61. DOI: 10.1016/j.scienta.2009.12.003.