Fingerprinting of Philippine Waling-Waling (Vanda sanderiana Rchb.f.) Accessions Using Simple Sequence Repeat (SSR) Markers

Vanda sanderiana is one of the most popular and highly prized Philippine orchids locally known as "Waling-waling". This orchid is a commercially important species for it is a frequently selected parent in the hybridization and production of modern vandaceous hybrids. This study aimed to develop the DNA fingerprint profile of 25 Vanda sanderiana accessions mostly originated from Mindanao using 52 publicly available orchid simple sequence repeat (SSR) markers. Twenty-three screened SSR markers produced polymorphic band profiles. The number of banding patterns observed ranged from 2 to 12 with molecular band sizes ranged from 95 bp to 465 bp. The IPS 13 was a highly informative marker as it exhibited the highest number of banding patterns (BP) and had the most unique bands. The polymorphism information content (PIC) varied from 0.365 to 0.884 with an average of 0.705. Fifteen of the polymorphic SSR markers were able to generate a unique banding patterns (BP) that could distinguish 20 out of 25 Vanda sanderiana genotypes. Fingerprints of the accessions were established based on the BP of the ten highly polymorphic markers with a range of PIC values from 0.75 to 0.88. Dendrogram generated based on 117 alleles detected by the 23 markers clustered the accessions according to flower color and place of origin. Cluster analysis using the UPGMA method separated the pink-maroon types from white apple green forms of V. sanderiana. A medium level of genetic diversity was detected in SSR data (50%), indicating SSR markers are effective in measuring genetic diversity and portraying genetic relationships among the genotypes in the germplasm. The present investigation suggests the usefulness of the employed SSR markers in DNA fingerprinting for genotype identification, discrimination, genetic diversity, and selection of suitable parents for future breeding work on this Philippine orchid. The findings of this preliminary study are valuable references to test the authenticity of V. sanderiana genetic resources in the country.