Phenotypic Evaluation and Identification of Superior Persian Walnut (Juglans regia L.) Genotypes in Mazandaran Province, Iran

Document Type : Research Article


1 Department of Horticultural Science, Faculty of Agriculture and Natural Resources, Karaj Branch ,Islamic Azad University, Karaj, Iran

2 Department of Horticultural Science, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran

3 Temperate Fruits Research Center, Horticultural Science Research Institute, Agricultural Research, Education and Extension Organizations, Karaj, Iran

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


Huge genetic diversity of Persian walnut in Iran provides a great opportunity for walnut breeders to use it for introducing varieties with desirable traits. In this regard, evaluating the genetic diversity and introducing superior genotypes is the foundation step of a walnut breeding program. This study was conducted to exploit the genetic diversity in Savadkuh county, Mazandaran province, Iran to identify some superior genotypes during 2013-2016. In the first step, 91 seed-originated genotypes were selected based on questionnaire. In the second stage, the morphological characteristics of the selected genotypes were studied using two IPGRI and UPOV descriptors in 2015. The results showed that nut and kernel weight ranged between 7.3-16.7 g and 3.2-8.6 g, respectively. Also, kernel percentage and shell thickness varied from 36 to 60.74% and from 0.8 to 2.8 mm, respectively. According to the morphological evaluation, 9 out of 91 genotypes (SR7, SR8, SR14, SR23, SR24, SR33, SR52, SR60 and SR83) were selected as superior genotypes. The selected superior genotypes were morphologically evaluated for two consecutive years (2015-2016). These superior walnut genotypes had high yield, lateral bearing habit (45-60%), heavy (13.4-16.7 g) and large nuts, high kernel percentage (48.6-56.6%), thin to moderate shell (1.1-1.6 mm) with light kernel color. Due to distinct and desirable characteristics, the selected superior genotypes can not only be used as parents in the further breeding program, but also some of them have the potential to release as commercial varieties.


Akca Y, Ozongun S (2004) Selection of late leafing, late flowering, laterally fruitful walnut (Juglans regia) types in Turkey. New Zealand Journal of Crop and Horticultural Science. 32(4), 337–342.
Akça Y, Yuldaşulu YB, 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.
Arzani K, Mansouri-Ardakan H, Vezvaei A, Roozban MR (2008) Morphological variation among Persian walnut (Juglans regia L.) genotypes from central Iran. New Zealand Journal of Crop and Horticultural Science. 36, 159-168.
Aslantaş R (2006) Identification of superior walnut (Juglans regia L) genotypes in north-eastern Anatolia, Turkey. New Zealand Journal of Crop and Horticultural Science. 34(3), 231–237.
Atefi J (1997) study on phenological and pomological characters on walnut promising clones in Iran. Acta Horticulturae. 442, 101–108.
Bernard A, Marrano A, Donkpegan A, Brown PJ, Leslie CA, Neale DB, Lheureux F, Dirlewanger E (2020). Association and linkage mapping to unravel genetic architecture of phenological traits and lateral bearing in Persian walnut (Juglans regia L.). BMC Genomics. 21(1), 1-25.
Cosmulescu S, Botu M (2012) Walnut biodiversity in South-Western Romania-Resource for perspective cultivars. Pakistan Journal of Botany. 44(1), 307–311.
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.
Ebrahimi A, Zarei A, Fatahi R, Varnamkhasti MG (2009) Study on some morphological and physical attributes of walnut used in mass models. Scientia Horticulturae. 121(4), 490–494.
Eskandari S, Hassani D, Abdi A (2005) Investigation on genetic diversity of Persian walnut and evaluation of promising genotypes. Acta Horticulturae. 705, 159-166.
FAO (2018) FAO statistical yearbook. Food and Agricultural Organization of the United Nations. http://faostatfaoorg/site/567/defaultaspx.
Forde HI, McGranahan GH (1996) Walnuts. In: Janick J, Moore JN (eds.), Fruit Breeding, Volume III: Nuts, Purdue University Press.pp. 241-273.
Ghanbari A, Faraji M, Behnamian M, Estaji A, Pyrayesh A, Fahim S (2019) Genetic diversity evaluation of some walnut (Juglans regia L.) genotypes in Meshkin-Shahr by ISSR marker. Journal of Nuts. 10(1), 1-8.
Hansche PE, Beres V, Forde HI (1972) Estimates of quantitative genetic properties of walnut and their implications for cultivar improvement. Journal of the American Society for Horticultural Science. 97, 279–285.
Hartmann HT, Kester DE, Davies FT, Geneve RL (1997). Plant propagation: Principles and practices, 6th edition. Prentice Hall, USA. pp. 250-280.
Hassani D, Mozaffari MR, Soleimani A, Dastjerdi R, Rezaee R, Keshavarzi M, Vahdati K, Fahadan A, Atefi J (2020a) Four new Persian walnut cultivars of Iran: Persia, Caspian, Chaldoran, and Alvand. HortScience. 55(7), 1162-1163.
Hassani D, Sarikhani S, Dastjerdi R, Mahmoudi R, Soleimani A, Vahdati K (2020b) .Situation and recent trends on cultivation and breeding of Persian walnut in Iran. Scientia Horticulturae. 270, 109369.
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), 259-71.
Ipek M, Arıkan Ş, Pırlak L, Eşitken A (2019) Phenological, morphological and molecular characterization of some promising walnut (Juglans regia L.) genotypes in Konya. Erwerbs-Obstbau. 61(2), 149-156.
IPGRI (1994) Descriptors for walnut (Juglans spp.). International Plant Genetic Resources Institute. Rome, Italy.
Khadivi-Khub A, Ebrahimi A (2015) The variability in walnut (Juglans regia L.) germplasm from different regions in Iran. Acta Physiologiae Plantarum. 37(3), 57.
Khorami SS, Arzani K, Roozban MR (2012) Identification and selection of twelve walnut superior and promising genotypes in Fars Province, Iran. Seed and Plant Improvement Journal. 28 (2), 277-296.
Koyuncu MA, Ekinci Kamil, Savran E (2004) Cracking characteristics of walnut. BiosystemsEngineering. 87(3), 305-311.
Ma J, Amos CI (2012) Principal components analysis of population admixture. PloS One. 7(7), e40115.
Mahmoodi R, Dadpour MR, Hassani D, Zeinalabedini M, Vendramin E, Micali S, Nahandi FZ (2019) Development of a core collection in Iranian walnut (Juglans regia L.) germplasm using the phenotypic diversity. Scientia Horticulturae. 249, 439-448.
Mahmoodi R, Hassani D, Amiri ME, Jaffaraghaei M (2016) Phenological and pomological characteristics of five promised walnut genotypes in Karaj, Iran. Journal of Nuts. 7 (1), 1-8.
Mehlenbacher SA (2003) Progress and prospects in nut breeding. Acta Horticulturae. 622, 57–79.
Ozkan G, Koyuncu MA (2005) Physical and chemical composition of some walnut (Juglans regia L) genotypes grown in Turkey. Grasas y Aceites. 56(2), 141–146.
Parsa J, Gregorian V, Talaei A, Khalighi A (2001) Comparative studies on the morphobiological characteristics of a Persian walnut (Juglans regia L) population for selecting the superior genotypes. Journal of Horticultural Science and Technology. 4(2), 95-108. [In Persian].
Ramos DE (1997). Walnut industry in the world: Prospects for research & production. Acta Horticulturae. 442, 419-423.
Rezaee R, Hasani G, Hassani D, Vahdati K (2008) Morphobiological characteristics of some
newly selected walnut genotypes from seedling collection of Kahriz – Orumia. Journal of
Horticultural Science and Technology. 9 (3), 205-214. [In Persian].
Rezaei A, Arzani K, Sarikhani S (2020) Morphological evaluation and identification of walnut (juglans regia L.) superior genotypes in north hamedan province of Iran. Iranian Journal of Horticultural Science. 51(2), 441-457
Ros E, Mataix J (2006) Fatty acid composition of nuts–implications for cardiovascular health. British Journal of Nutrition. 96(S2), S29–S35.
Sarikhani Khorami S, Arzani K, Karimzadeh G, Shojaeyan AA, Ligterink W (2018) Genome size; a novel predictor of nut weight and nut size of walnut trees. HortScience. 53, 275-282.
Sarikhani Khorami S, Arzani K, Roozban MR (2014) correlations of certain high-heritability horticultural traits in Persian walnut (Juglans regia L.). Acta Horticulturae. 1050, 61-68.
Sarikhani S, Arzani K, Karimzadeh G, Shojaeiyan A (2017) Morphological characteristics, protein contents and fatty acids composition of some walnut (Juglans regia L.) superior genotypes in the north of Fars province. Seed and Plant Production Journal. 33(2), 163-184.
Sarikhani S, Vahdati K, Ligterink W (2021) Biochemical properties of superior Persian walnut genotypes originated from southwest of Iran. International Journal of Horticultural Science and Technology. 8(1), 13-24.
Sharma SD, Sharma OC (1998) Studies on the variability in nuts of seedlings walnut (Juglans regia L.) in relation to the tree age. Fruit Varieties Journal. 52(1), 20–23.
Sharma SD, Sharma OC (2001) Genetic divergence in seedling trees of Persian walnut (Juglans regia L.) for various metric nut and kernel characters in Himachal Pradesh. Scientia Horticulturae. 88, 163-171.
Vahdati K, Arab MM, Sarikhani S, Sadat-Hosseini M, Leslie CA, Brown PJ (2019) Advances in Persian walnut (Juglans regia L.) breeding strategies. In: Al-Khayri J, Jain S, Johnson D (eds) advances in plant breeding strategies: nut and beverage crops. Springer, Cham.
Vahdati K, Hassani D, Rezaee R, Jafari Sayadi MH, Sarikhani Khorami S (2014) .Walnut footprint in Iran. In Avanzato D, McGranahan GH, Vahdati K, Botu M, Iannamico L, Assche JV (Eds.). following walnut footprints (Juglans regia L.) cultivation and culture, folklore and history, Traditions and Uses Scripta Horticulturae. 17, 187-201.
Vahdati K, Pourtaklu SM, Karimi R, Barzehkar R, Amiri R, Mozaffari M, Woeste K (2015) Genetic diversity and gene flow of some Persian walnut populations in southeast of Iran revealed by SSR markers. Plant Systematics and Evolution. 301(2), 691-699.
Vahdati K, Sarikhani Khorami S, Arab MM (2018) Walnut: a potential multipurpose nut crop for reclaiming deteriorated lands and environment. Acta Horticulturae. 1190, 95-100.
Yarilgac T, Koyuncu F, Koyuncu MA, Kazankaya A, Sen SM (2001) Some promising walnut selections (Juglans regia L.). Acta Horticulturae. 544, 93–96. 
Zeneli G, Kola H, Dida M (2005) Phenotypic variation in native walnut populations of Northern Albania. Scientia Horticulturae. 105(1), 91–100.