Molecular characterization in monopodial orchid hybrids

Random amplified polymorphic DNA (RAPD) analysis was employed for the molecular characterization of the 20 monopodial orchid hybrids. The eight primers, selected from the 70 initially screened primers, generated 57 scorable bands of which six were monomorphic and the remaining 51 were polymorphic (89.47%). All primers produced polymorphic amplification products, however, the extent of polymorphism varied with each primer. Statistical analysis was carried out using NTSYS-PC software and a dendrogram was generated using Jaccard's similarity coefficients. The overall similarity coefficient ranged from 0.40 to 0.84. Cluster analysis revealed that at 0.69 similarity coefficient, the 20 monopodial orchid hybrids got divided into six groups. Among the 20 hybrids, H-18, H-7, H-13, H-17, H-19 and H-20 stood separately in clusters II, III A, III B, IV, V and cluster VI respectively. The grouping of hybrids in the cluster was largely consistent with what is known about their breeding history. The cluster based on RAPD analysis using eight primers clearly demonstrates the existence of genetic variation within the 20 monopodial orchid hybrids.