Dataset of chloroplast intergenic spacer sequences and candidate DNA markers for species identification in Hoya (Apocynaceae) based on the plastome of Hoya lockii V.T. Pham & Aver. from Vietnam

Hoya lockii V.T. Pham & Aver. is an epiphytic species that exhibits strong morphological similarity to several closely related congeners, which may hinder accurate species identification, especially when specimens are incomplete or degraded. This article presents a curated dataset of chloroplast intergenic spacer sequences to support molecular identification and phylogenetic assessment of H. lockii . The dataset includes six plastid intergenic spacer regions ( trnK–rps16, psbI–atpA, trnH–psbA, psbK–psbI, ndhC–trnV, and rbcL–accD ) extracted from complete chloroplast genomes. Phylogenetic analyses based on individual loci revealed variation in topological resolution and bootstrap support among regions. Among them, the markers psbI–atpA and ndhC–trnV showed relatively strong phylogenetic signals. In the ndhC-trnV tree, H. lockii formed a well-supported clade with Hoya exilis (bootstrap = 99%). In the psbI–atpA tree, H. lockii was recovered as the sister of Hoya lanceolata , with strong bootstrap support (99%). Multilocus phylogenetic reconstruction based on concatenated alignments of six intergenic spacers further improved tree stability and resolution, recovering H. lockii as the sister taxon of H. exilis with strong bootstrap support (100%). These results indicate that psbK–psbI, psbI–atpA , and ndhC–trnV , together with the concatenated dataset, represent potential DNA marker candidates to support species identification within the genus Hoya . The dataset provides a reproducible molecular resource that may facilitate phylogenetic analysis, DNA barcoding, and taxonomic studies of Hoya and related taxa in Apocynaceae.