Abstract

The Quercus L. (Fagaceae) represents a complex taxonomic genus with approximately 600 extant species of significant ecological and economic importance. Accurate species identification remains challenging due to frequent hybridization and morphological similarities. This study influences DNA barcoding as a powerful molecular approach to distinguish Q. floribunda L., a species native to the Himalayan regions of Pakistan. In the current study, three chloroplast DNA barcoding loci, the rpoB, rbcL and tRNA, were investigated to assess their effectiveness in Q. floribunda L. identification and Phylogenetics. The research employed comprehensive molecular techniques to evaluate genetic diversity and evolutionary relationships of Q. floribunda L. The rpoB gene revealed the highest discriminatory power, exhibiting superior haplotype diversity, and provided insights into relationships between Q. floribunda L. and other Quercus species, with rpoB showing 14 haplotypes, 5 rbcL, and 8 tRNA. Phylogenetic analysis placed Q. floribunda L. in a shared ancestral node with Q. variables for rpoB, while rbcL showed high similarity with Q. aucheri. The tRNA spacer revealed evolutionary divergence across Quercus species, classifying sequences into four major clades. In conclusion, all the barcode regions demonstrated considerable diversity among Quercus species, supporting their utility as barcodes for identification. This barcoding study represents the first comprehensive analysis on Quercus from the Himalayan region of Pakistan. The findings contribute to accurate species identification, phylogenetic understanding, and conservation efforts for this ecologically important oak species. This research also highlights the potential of DNA barcoding in resolving taxonomic uncertainties and its application in biodiversity conservation and management of Quercus and other valuable plant resources.