Assessment of genetic fidelity in somaclonal variants with cytological and RAPD analysis in Oroxylum indicum (L.) Vent.-An endangered medicinal tree

Random amplified polymorphic DNA (RAPD) markers were used to verify the clonal fidelity in in vitro regenerated plants of Oroxylum indicum (L.) Vent. (Bignoniaceae). Deviation from normal/natural leaf shape and branching pattern was detected in indirectly (from callus) regenerated plants. Percentage of phenotypical variation was observed and calculated upto five subculture passages. RAPD profiles of directly (from axillary bud) and indirectly regenerated plants were compared with mother plant. To screen the genetic variation 20 arbitrary decamers were used to study of randomly selected nature grown plant as well as direct and indirect regenarants. Genetic variation among nature grown and direct regenerants was 10%, whereas 24.59% polymorphism frequency was estimated for indirect plantlets. These results indicate that the regeneration of plants through axillary bud culture is a low-risk method for generating genetic variability, whereas material regenerated through callus has genetic variation, resulting in the formation of somaclones. Cytological studies of cells of callus, root tip of directly and indirectly regenerated plants showed the incidence of polyploidy.