Molecular genetic homogeneity assessment of micropropagated Dendrobium moschatum Sw. - A rare medicinal orchid, using RAPD and ISSR markers

Generation of true-to-type plant is one of the most important aspects in germplasm conservation through micropropagation. In this study, reliable in vitro protocols were established for the generation of genetically stable plants of Dendrobium moschatum using seed explants via protocorm formation. Thidiazuron (TDZ) and 6-benzyl aminopurine (BAP) induced effective shooting when incorporated individually or in combination with auxins in the medium. High shooting response was observed in Mitra medium either with 2.4 mgL−1BAP or 1.2 mgL−1TDZ and 1.2 mgL−11-naphthyl acetic acid (NAA). Indole-3-butyric acid (IBA) or NAA produced better root multiplication in the culture than indole -3- acetic acid (IAA). Medium with 1.2 mg L−1 TDZ + 1.2 mgL−1 IBA or 1.2 mg L−1 TDZ + 1.2 mg L−1 NAA generated a good rooting response. Random Amplified Polymorphic DNA (RAPD) and Inter Simple Sequence Repeats (ISSR) markers analysis showed 95.2% and 98% genetic monomorphism respectively among in vitro regenerants and the mother plant. Nei’s genetic distance ranged from 0.00 to 0.044 disclosing high genetic similarity among the regenerants. The Unweighted Pair Group Method with Arithmetic Mean (UPGMA) based dendrograms generated from RAPD and ISSR marker analysis also revealed high genetic proximity between mother and micropropagated plants. Principal Coordinate Analysis (PCoA) further confirmed the grouping of plants in accordance with UPGMA dendrograms. Correlation analysis between the matrices of markers revealed higher efficiency of ISSR over RAPD markers. This is the first report of genetic homogeneity testing of in vitro propagated Dendrobium moschatum using molecular markers.