Document Type : Research paper


1 Department of Horticulture, College of Aburaihan, University of Tehran, Tehran, Iran

2 Wageningen Seed Lab, Laboratory of Plant Physiology, Wageningen University (WU), Wageningen, The Netherlands


Evaluation of genetic diversity and identification of superior genotypes is a fundamental step
in walnut breeding programs. In addition, information on biochemical properties of superior
genotypes can help walnut breeders to release commercial varieties with high kernel quality.
To gain more information on superior genotypes, a walnut population located in southwest of
Iran was morphologically evaluated from 2010 to 2016. Based on important walnut breeding
traits, nine superior walnut genotypes were selected from a total of 612 tested genotypes.
These genotypes were characterized by high yield, moderate to late-leafing, lateral bearing,
thin shell and large nuts with light and extra-light kernel color. Biochemical traits of the
selected superior genotypes were evaluated for two consecutive years (2017 and 2018) and a
high variation was observed among genotypes in respect of oil, protein and total phenol
contents. Oil, protein and phenol contents of walnut kernels ranged between 57.9 to 69.6%,
13.0 to18.1% and 46.6 to 61.5 mg GAE g-1, respectively. Polyunsaturated fatty acids (PUFA),
monounsaturated fatty acids (MUFA) and saturated fatty acids (SFA) constituted on average
63.8%, 26.7% and 9.7% of fatty acid content, respectively. There was a negative correlation
between some phenological traits and oil and protein contents. Lateral bearing genotypes had
darker kernels with higher amounts of saturated fatty acids. In general, the selected walnut
genotypes not only are superior in various aspects of phenotypic characteristics, but also have
high kernel quality and nutritional value which can be used as a source of desirable genes for
future walnut breeding programs.


Akbari V, Heidari R, Jamei R. 2015. Fatty acid compositions and nutritional value of six walnut (Juglans regia L.) cultivars grown in Iran. Advanced Herbal Medicine 1(1), 36-41.
2. Akça Y, Yuldaşulu Y, Murad E, Vahdati K. 2020. Exploring of Walnut Genetic Resources in Kazakhstan and Evaluation of Promising Selections. International Journal of Horticultural Science and Technology, 7(2), 93-102.
3. Amaral J.S, Alves M.R, Seabra R.M, Oliveira B.P. 2005. Vitamin E composition of walnuts (Juglans regia L.): a 3-year comparative study of different cultivars. Journal of Agricultural and Food Chemistry 53(13), 5467-5472.
4. Amaral J.S, Casal S, Pereira J.A, Seabra R.M, Oliveira B.P. 2003. Determination of sterol and fatty acid compositions, oxidative stability, and nutritional value of six walnut (Juglans regia L.) cultivars grown in Portugal. Journal of Agricultural and Food Chemistry 51(26), 7698-7702.
22 Int. J. Hort. Sci. Technol; Vol. 8, No. 1; March 2021
5. Amiri R, Vahdati K, Mohsenipoor S, Mozaffari M.R, Leslie C. 2010. Correlations between some horticultural traits in walnut. HortScience 45(11), 1690-1694.
6. Amtul Z, Uhrig M, Wang L, Rozmahel R.F, Beyreuther K. 2012. Detrimental effects of arachidonic acid and its metabolites in cellular and mouse models of Alzheimer's disease: structural insight. Neurobiology of Aging 33(4), 831-e21.
7. AOAC. 1995. Official Methods of Analysis, sixteenth ed. Association of Official Analytical Chemists, Arlington, VA.
8. Arzani K, Mansouri Ardakan H, Vezvaei A, Roozban M.R. 2008. Morphological variation among Persian walnut (Juglans regia) genotypes from central Iran. New Zealand Journal of Crop and Horticultural Science 36(3), 159-168.
9. Aslantas R. (2006). Identification of superior walnut (Juglans regia) genotypes in north‐eastern Anatolia, Turkey. New Zealand Journal of Crop and Horticultural Science 34(3), 231-237.
10. Bouabdallah I, Bouali I, Martínez-Force E, Albouchi A, Perez Camino M.D.C, Boukhchina S. 2014. Composition of fatty acids, triacylglycerols and polar compounds of different walnut varieties (Juglans regia L.) from Tunisia. Natural Product Research 28(21), 1826-1833.
11. Bourre J.M. 2005. Dietary omega-3 fatty acids and psychiatry: mood, behavior, stress, depression, dementia and aging. Journal of Nutrition, Health & Aging 9(1), 31-8.
12. Chatrabnous N, Yazdani N, Vahdati K. 2018. Determination of nutritional value and oxidative stability of fresh walnut. Journal of Nuts 9(1), 11-20.
13. Dogan, M, Akgul, A. 2005. Fatty acid composition of some walnut (Juglans regia L.) cultivars from east Anatolia. Grasas y aceites 56(4), 328-331.
14. Ebrahimi A, Khadivi-Khub A, Nosrati Z, Karimi R. 2015. Identification of superior walnut (Juglans regia) genotypes with late leafing and high kernel quality in Iran. Scientia Horticulturae, 193, 195-201.
15. FAO. 2018. FAO statistical yearbook. Food and Agriculture Organization of the United Nations (
16. Gandev S. 2007. Budding and grafting of the walnut (Juglans regia L.) and their effectiveness
in Bulgaria. Bulgarian Journal of Agricultural Science 13(6), 683.
17. Ghanbari A, Faraji M, Shokouhian A, Pyrayesh A. 2018. Evaluation of Quantitative and Qualitative Characteristics of Persian Walnut (Juglans regia L.) Genotypes in the West of Meshkin-Shahr. Journal of Nuts 9(1), 57-65.
18. Hassankhah A, Vahdati K, Rahemi M, Hassani D, Sarikhani Khorami S. 2017. Persian Walnut phenology: effect of chilling and heat requirements on budbreak and flowering date. International Journal of Horticultural Science and Technology 4(2), 259-271.
19. Hayes D, Angove M.J, Tucci J, Dennis C. 2016. Walnuts (Juglans regia) chemical composition and research in human health. Critical reviews in food science and nutrition, 56(8), 1231-1241.
20. INC. 2019. Nuts and dried fruits, Statistical yearbook. International Nut and Dried Fruits Press: 80 pp.
21. IPGRI. 1994. Descriptors for walnut (Juglans spp.). Rome, Italy, International Plant Genetic Resources Institute: 51 pp.
22. Jahanbani R, Ghaffari M, Vahdati K, Salami M, Khalesi M, Sheibani N, Moosavi-Movahedi A.A. 2018. Kinetics study of protein hydrolysis and inhibition of angiotensin converting enzyme by peptides hydrolysate extracted from walnut. International Journal of Peptide Research and Therapeutics, 24(1), 77-85.
23. Jahanbani R, Ghaffari S.M, Salami M, Vahdati K, Sepehri H, Sarvestani N.N, Sheibani N, Moosavi-Movahedi A.A. 2016. Antioxidant and anticancer activities of walnut (Juglans regia L.) protein hydrolysates using different proteases. Plant Foods for Human Nutrition 71(4), 402-409.
24. Khadivi-Khub A, Ebrahimi, A, Mohammadi A, Kari A. 2015. Characterization and selection of walnut (Juglans regia L.) genotypes from seedling origin trees. Tree Genetics & Genomes, 11(3), 54.
25. Khodadadi F, Tohidfar M, Mohayeji M, Dandakar A.M, Leslie C, Butterfield T, Kluepfel D. Vahdati K, 2016. Induction of polyphenol oxidase in walnut and its relationship to the pathogenic response to bacterial blight. Journal of American Society for Horticultural Science. 141:119-124
26. Khodadadi F, Tohidfar M, Vahdati, K, Dandakar A.M, Leslie C.A. 2020. Functional analysis of walnut polyphenol oxidase gene (JrPPO1) in transgenic tobacco plants and PPO
Biochemical Properties of Superior Persian Walnut Genotypes Originated from … 23
induction in response to walnut bacterial blight. Plant Pathology, 00: 1-9.
27. Khorami S.S, Arzani K, Karimzadeh G, Shojaeiyan A, Ligterink W. 2018. Genome size: A novel predictor of nut weight and nut size of walnut trees. HortScience 53(3): 275-282.
28. Kodad O, Estopañán Muñoz G, Juan Esteban T, Sindic M. 2016. Genotype and year variability of the chemical composition of walnut oil of Moroccan seedlings from the high Atlas Mountains. Grasas y Aceites 67(1): 1-8.
29. Korner C, Basler D. 2010. Phenology under global warming. Science 327 (5972), 1461-1462.
30. Labuckas D.O, Maestri D.M, Perello M, Martínez M.L, Lamarque A.L. 2008. Phenolics from walnut (Juglans regia L.) kernels: Antioxidant activity and interactions with proteins. Food Chemistry 107(2), 607-612.
31. Li L, Tsao R, Yang R, Liu C, Zhu H, Young J.C. 2006. Polyphenolic profiles and antioxidant activities of heartnut (Juglans ailanthifolia var. cordiformis) and Persian walnut (Juglans regia L.). Journal of agricultural and food chemistry, 54(21), 8033-8040.
32. Mao X, Hua Y. 2012. Composition, structure and functional properties of protein concentrates and isolates produced from walnut (Juglans regia L.). International Journal of Molecular Science 13: 1561-1581.
33. Martínez M.L, Maestri D.M. (2008). Oil chemical variation in walnut (Juglans regia L.) genotypes grown in Argentina. European Journal of Lipid Science and Technology 110(12), 1183-1189.
34. Martínez M.L, Labuckas D.O, Lamarque A.L, Maestri D.M. 2010. Walnut (Juglans regia L.): genetic resources, chemistry, by‐products. Journal of the Science of Food and Agriculture 90(12), 1959-1967.
35. Ozcan M.M. 2009. Some nutritional characteristics of fruit and oil of walnut (Juglans regia L.) growing in Turkey. Iranian Journal of Chemistry and Chemical Engineering 28(1), 57-62.
36. Pereira J.A, Oliveira I, Sousa A, Ferreira I.C, Bento A, Estevinho L. 2008. Bioactive properties and chemical composition of six walnut (Juglans regia L.) cultivars. Food and Chemical Toxicology, 46(6), 2103-2111.
37. Rabrenović B, Dimić E, Maksimović M, Šobajić S, Gajić-Krstajić L. 2011. Determination of fatty acid and tocopherol compositions and the oxidative stability of walnut (Juglans regia L.)
cultivars grown in Serbia. Czech Journal of Food Sciences 29(1), 74-78.
38. Roozban, M.R, Mohamadi. N. Vahdati K. 2005. Fat content and fatty acid composition of four Iranian pistachio varieties grown in Iran. Acta Horticulturae. 726: 573-577.
39. Ros E, Núñez I, Pérez-Heras A, Serra M, Gilabert R, Casals E, Deulofeu R. 2004. A walnut diet improves endothelial function in hypercholesterolemic subjects: a randomized crossover trial. Circulation 109 (13), 1609-1614.
40. Sarikhani Khorami S, Arzani K, Roozban M.R. 2012. Identification and selection of twelve walnut superior and promising genotypes in Fars Province, Iran. Seed and Plant Improvement Journal 28 (2):277-296.
41. Sarikhani Khorami S, Arzani K, Roozban M.R. 2014. Correlations of certain high-heritability horticultural traits in Persian walnut (Juglans regia L.). Acta Horticulturae, 1050: 61-68
42. Simsek M, Yilmaz K.U, Demirkiran A.R. 2010. Selection and determination of some significant properties of superior walnut genotypes. Scientific Research and Essays 5(19), 2987-2996.
43. Siqueira A.P.S, Pacheco M.T.B, Naves M.M.V. 2015. Nutritional quality and bioactive compounds of partially defatted baru almond flour. Food Science and Technology 35(1), 127-132.
44. Vahdati K, Arab M.M, Sarikhani S, Sadat Hosseini M, Leslie C.A, Brown P.J. 2019. Advances in Walnut Breeding Strategies. In: Al-Khayri, J.M, Jain, S.M. and Johnson, D.V. (Eds.). Advances in Plant Breeding Strategies: Nut and Beverage Crops. Springer Press.
45. Vahdati K, Hassani D, Rezaee R, Jafari Sayadi M.H, Sarikhani Khorami S. 2014. Walnut footprint in Iran. In: Avanzato, D, McGranahan, G. H, Vahdati, K, Botu, M, Iannamico, L, and Assche, J.V (Eds.). Following Walnut Footprints (Juglans regia L.) Cultivation and Culture, Folklore and History, Traditions and Uses Scripta Horticulturae; 17: 187-201.
46. Wirasnita R, Hadibarata T, Novelina Y.M, Yusoff A.R.M, Yusop Z. 2013. A modified methylation method to determine fatty acid content by gas chromatography. Bulletin of the Korean Chemical Society 34(11), 3239-3242.
47. Yılmaz S, Akça Y. 2017. Determination of biochemical properties and fatty acid composition of new walnut (Juglans regia) genotypes. Journal of Agricultural Faculty of Gaziosmanpasa University 34, 74-80.
24 Int. J. Hort. Sci. Technol; Vol. 8, No. 1; March 2021
48. Zeneli G, Kola, H, Dida, M. 2005. Phenotypic variation in native walnut populations of Northern Albania. Scientia Horticulturae 105(1), 91-100.
49. Zhang LS, Tan Y, Ouyang Y.L, Wang R.S. 1991. Effects of high erucic acid rapeseed oil on fatty acid oxidation in rat liver. Biomedical and Environmental Sciences 4(3), 262-267.
50. Zhang Z, Liao L, Moore J, Wu T, Wang Z. 2009. Antioxidant phenolic compounds from walnut kernels (Juglans regia L.). Food Chemistry 113(1), 160-165.
51. Zwarts L, Savage G.P, McNeil D.L. 1999. Fatty acid content of New Zealand-grown walnuts (Juglans regia L). International Journal of Food Sciences and Nutrition 50(3), 189-194.