SSR-Based Assessment of Genetic Diversity in Iranin Walnut (Juglans regia L.)

Document Type : Research Paper

Authors

Urmia University

Abstract

Genetic variation assessment in plant gene pools is the first step in identifying, maintaining and conserving the genetic resources and also the basis for breeding programs. Molecular markers provide the important tools to evaluate the genetic diversity in native plants. In order to evaluate the genetic diversity of 62 Iranian walnut seedlings, 10 SSR primer pairs were used. The used SSR loci generated 53 alleles. The minimum and maximum number of alleles were for SSR loci WGA69, WGA71 (4 alleles) and WGA1 (7 alleles), respectively. The most value of observed heterozygosity was recorded by loci WGA276. All used SSR loci showed deviation from Hardy–Weinberg equilibrium (p≤0.01). UPGMA cluster analysis using Dice similarity coefficient classified four groups among 62 studied walnuts. Population structure analyses using Structure 2.3.1 software identified two possible groups (k=2). Membership coefficient matrix and Fst values of the each identified subgroup indicated no remarkable differentiation among the subgroups. In conclusion, information obtained from the current study could be useful for identification of the seedlings with enough genetic distance in walnut hybrid production programs to exploit the heterosis.

Keywords


[1]. Gerard, W.K., Crocker, T.F., and Bertrand, P.F. (2003). Minor Fruits and Nuts in Georgia. University of Georgia, 214 p.
[2]. Ducci, F., Rogatis, A., and Proietti, R. (1997). Protezione delle risorse genetiche di Juglans regia L. Annali Istituto Sperimentali Selvicultura, 26: 35–55.
[3]. McGranahan, G.H., Charles, A., Leslie, C.A., Philips, H.A., and Dandaker, A. (1998). Walnut Propagation. In: D. Ramos (ed.), Walnut Production Manual, University of California, DANRPubl., Davis, pp 71-83.
[4]. Sehgal, D., and Raina, S.N. (2008). DNA markers and germplasm resource diagnostics: new perspectives in crop improvement and conservation strategies. In: Arya ID, Arya S (eds) Utilization of biotechnology in plant sciences. Microsoft Printech (I) Pvt. Ltd, Dehradun, pp 39–54.
[5]. Vahdati, K., and Zareie, N. (2006). Evaluation of side-stub and hypocotyle grafting efficiency for walnut propagation in Iran. Acta Horticulturae, 705: 175-179.
[6]. Ruiz-Garcia, L., Lopez-Ortega, G., Fuentes Denia, A., and Frutos Tomas, D. (2011). Identification of a walnut (Juglans regia L.) germplasm collection and evaluation of their genetic variability by microsatellite markers. Spanish Journal of Agricultural Research, 9(1): 179-192.
[7]. Aly, M.M., Robert, A., Fjellstrom, G., McGranahan, G.H., and Parfitt, E. (1992). Origin of walnut somatic embryos determine by RFLP and Isozyme analysis. Hort Science, 27(1): 61-63.
[8]. Niceses, F.P., Hormaza, J.I., and McGranahan, G.H. (1998). Molecular characterization and genetic relatedness among walnut (Juglans regia L.) genotypes based on RAPD markers. Euphytica, 101:199-206.
[9]. Bayazit, S., Kazan, K., Golbitti, S., Cevik, V., Ayanogla, H., and Ergul, A. (2007). AFLP analysis of genetic diversity in low chill requiring walnut (Juglans regia L.) genotyping from Hatay. Turkey, Scientia Horticulturae, 111: 394-398.
[10]. Foroni, I., Woeste, K., Monti, L.M., and Rao, R. (2007). Identification of ‘Sorrento’ walnut using simple sequence repeats (SSRs). Genetic Resources and Crop Evolution, 54:1081-109.
[11]. Nazeer Ahmed, J.I.M., ReyazulRouf, M., Nazir Ahmad, R., Rizwan, R., Shabir, H., Wani WajidaShafi Hidayatullah, M., and Sheikh, M.A. (2012). SSR and RAPD analysis of genetic diversity in walnut (Juglans regia L.) genotypes from Jammu and Kashmir, India. Physiology and Molecular Biology of Plants, 18(2): 149–160.
[12]. Mahmoodi, R., Rahmani, F., and Rezaee, R. (2013). Genetic diversity among Juglans regia L. genotypes assessed by morphological traits and microsatellite markers. Journal of Agricultural Research, 11(2), 431-437.
[13]. Dangl, G.S., Woeste, K.E., Aradhya, M.K., Koehmstedt, A., Simon, C., Potter, D., Leslie, C.A., and McGranahan, G.H. (2005). Characterization of fourteen microsatellite markers for genetic analysis and cultivar identification of walnut. Journal of the American Society for Horticultural Science, 130(3): 348-354.
[14]. Peakall, R., and Smouse, P.E. (2006). GENALEX 6.4: Genetic analysis in Excel. Population genetic software for teaching and research. Molecular Ecology Notes, 6: 288 -295.
[15]. Rohlf, F.J. (1998). NTSYSpc: Numerical Taxonomy and Multivariate Analysis System Version 2.0. Setauket, New York.
[16]. Pritchard, J.K., Stephens, M., and Donnelly, P. (2000). Inference of population structure using multilocus genotype data. Genetics, 155:945-959.
[17]. Foroni, I., Woeste, K., Monti, L.M., and Rao, R. (2006). Identification of ‘Sorrento’ walnut using simple sequence repeats (SSRs). Genetic Resources and Crop Evolution, 85: 311-321.
[18]. Victory, E.R., Glaubitz, J.C., Rhodes, O.E., and Woeste, K.E. (2006). Genetic homogeneity in Juglans nigra (Juglandaceae) at nuclear microsatellites. American Journal of Botany, 93:118-126.
[19]. Karimi, R., Ershadi, A., and Vahdati, K. (2008). Analysis of Genetic Diversity Among Some Persian Walnut Populations of  Hamedan Province Using SSR Markers. Plant Production Technology, 9(2): 43-53. (In Farsi).
[20]. Fornari, B., Malvolti, M.E., Taurchini, D., Fineschi, S., Beritognolo, I., McCaglia, E., and Cannata, F. (2001). Isozym and organellar DNA analysis of genetic diversity in natural/naturalised European and Asiatic walnut (Juglans regia L.) populations. ActaHorticulturae, 544: 167-178.