Genetic diversity of superior Persian walnut genotypes in Azadshahr, Iran

• DOI: 10.1007/s12298-018-0573-9
• Publication Date: 2018-07-02T13:19:51Z
• Authors: Fatemeh Shamlu; Mehdi Rezaei; Shaneka Lawson; Aziz Ebrahimi; Abbas Biabani; Alireza Khan-Ahmadi
• Keywords: 0106 biological sciences; 0401 agriculture, forestry, and fisheries; 04 agricultural and veterinary sciences; 15. Life on land; 01 natural sciences; 6. Clean water

Persian walnut (Juglans regia L.) is known to have originated in central and eastern Asia. Remnants of these wild populations can still be found in the Hyrcanian forest in north-eastern Iran. In this study, 102 individual walnut trees from four geographic populations in the Azadshahr province (Vamenan, Kashidar, Rudbar and Saidabad) were sampled. We characterized individual trees using 28 standard morphological traits. The range of traits varied widely for some economically important characteristics including nut weight (6.1-19.79 g), kernel weight (2.9-9.4 g), and kernel fill percentage (26.51-60.34%). After morphological evaluation, 39 superior individuals based on nut quality and kernel fill percentage were selected for further genetic analysis. Individual superior trees were genotyped using 10 simple sequence repeat markers (SSR) and genetic diversity. Number of alleles per locus ranged from 3 (WGA005) to 12 (WGA054). Clustering analysis of 10 SSR loci divided the genotypes into three main groups. PCoA analysis clearly sorted genotypes into one of four distinctive groups which aligned with the cluster analysis. All analyses showed that individuals from Saidabad were genetically distinct. Likewise, results indicated that the high level of genetic diversity in Azadshahr region walnuts may provide a diverse source for superior walnuts in walnut breeding programs.