Abstract
Polyploidization has played a major role in plant evolution and can alter plant morphology, phenology, and ecology within only one or a few generations. Ziziphus species are economically as well as nutritionally important fruit-yielding trees. Identification of genotypes with unique traits or those with higher ploidy levels or a broader genetic base could lead to further improvements within the species. The current study has assessed the ploidy levels in the Ziziphus species (Ziziphus jujuba Mill. and Ziziphus nummularia (Burm. f. Wight & Arn) with phenotypic traits, flow cytometry, and chromosomal count as well as with SSRs markers. Morphological traits were inferred to be the most important drivers of trait variations among the investigated genotypes. The total sugar, total cAMPs, titratable acid, and chlorophyll (a, b, and total) were also significantly different in contrast with diploid plants, which showed that tetraploid Ziziphus had the potential to increase nutritional contents. Out of twenty (20), five (5) Z. jujuba genotypes (ZJL-9, ZJL-12, ZJL-17, ZJL-18, and ZJL-19) were found tetraploid 2n = 4x = 48, with genome size ranging from 965.9 to1238.8 Mb that was significantly higher than the tetraploid Z. jujuba Mill. variety Dongzao. Similarly, Z. nummularia ZNL-07 to ZNL-15 have found tetraploid 2n = 4x = 72 with genomic sizes ranging from 1152.2 to 1746.8 Mb respectively. Simple sequence repeats (SSRs) marker was applied to assess the genetic relationship within Ziziphus genotypes. To the best of our understanding, this is the first report on the identification of naturalized random tetraploids within the Pakistani Ziziphus species. This study provides important insights into the genomic architecture of Ziziphus species with implications for classification, conservation, and improvements of Ziziphus germplasm resources.