Molecular profiling and genetic relationship among ber (Ziziphus sp.) genotypes using RAPD markers

Genetic relationship study was performed with RAPD markers among 50 ber genotypes representing Z. mauritiana, Z. nummularia and Z. spina-christi. Out of 120 primers initially tested, 46 were highly reproducible and generated 368 RAPD markers with 86.2% polymorphism (316 polymorphic bands). The number of amplification product per primer ranged from 2 (OPF-9) to 17 (OPD-3) with an average of 8 bands per primer. The resolving power (Rp) for different primers ranged from 0.48 (OPE-4) to 9.37 (OPD-3) and polymorphic information content (PIC) ranged from 0.12 (OPD-20) to 0.82 (OPE-9). Nineteen primers distinguished at least one genotype that would prove to be highly useful for identification of genotype and designing future breeding strategy. Genetic relationships between the accessions were established based on Jacquard's similarity coefficient and it ranged from 26.3% to 78.9% suggesting that the Ziziphus germplasm is genetically diverse. UPGMA cluster analysis generated dendrogram with six clusters separating two wild genotypes, Z. nummularia (collection 1) and Z. spina-christi from rest of the genotypes. Cluster-I and II comprised of two genotypes each, whereas, the biggest cluster, cluster VI comprised of 20 out of remaining 44 genotypes. In cluster II to cluster-VI, genotypes were separated from each other at different similarity levels in successive branching. The present study has proved that ber genotype earlier reported to be similar based on morphology are genetically different. The degree of genetic variation detected in Ziziphus species with RAPD analysis in the present study suggests that it is an efficient marker technology for delineating genetic relationships among genotypes and estimating genetic diversity, thereby enabling the formulation of appropriate strategy for conservation and improvement programmes.