Assessing Genetic Variability and Population Structure of Ziziphus Nummularia as Characterized by Phenotypic Traits and SSR Markers with Climatic Distribution

Abstract Genus of Ziziphus (family Rhamnaceae), approximately 170 species of prodigious economic and ecological importance. Studies on the genetic diversity within Pakistani Ziziphus species are limited, and to date, no single report on the application of DNA barcoding attempt for identification of Ziziphus species is available in the literature. Therefore, the current study was designed to biogeographic distribution, to assess diversity based on phenotypic traits, SSRs markers, and relationships among Ziziphus nummularia (Burm.f.) Wight & Arn. genotypes. For the first time we use ArcGIS modeling, and their cartographic function for the identification of diversity in climatic variables such as temperature, mean diurnal, humidity, precipitation, and precipitation seasonality and the using of these techniques to determine the important variable which is responsible for the recent distribution of the Ziziphus species. A total of 11 phenotypic traits were noted and have significant phenotypic variation among the traits. The study has used 40 simple sequence repeats (SSR) markers for gaining insights into the genetic diversity within 180 genotypes of Z. nummularia. Successful amplification was achieved with 27 SSRs and was applied for understanding the population structure and relationships among the genotypes. A total of 120 alleles were amplified from Z. nummularia genotypes collected from three districts of the Malakand division, alleles per locus ranged from 2 to 6, averaging 4.4286. whereas polymorphism information content (PIC) from 0.332 to 0.794 in locus JSSR-490 and JSSR-97, within mean value was 0.671 per locus, expected heterozygosity (He), was 0.575, observed heterozygosity (Ho), 0.6618 and average gene diversity 0.494. Flow estimates (6.415) indicated frequent gene flow within Z. nummularia genotypes. Analysis of molecular variance (AMOVA) revealed high genetic variability (80%). The genetic relationship inferred from the neighbor-joining (NJ) phylogeny separate genotypes into three clusters and Bayesian model-based STRUCTURE analyses and PCoA analysis resolved all genotypes and indicted that the KP, populations, Swat and Buner, represent excesses of two different migration routes, with one designated from Swat and Dir (L). The overall results indicated the prevalence of genetic variability and relationships among Z. nummularia across geographical boundaries has retained unique alleles and this may facilitate the development of agronomically desirable and genetically improved Ziziphus cultivars and collections that can help achieve efficient conservation.