Gamma Radiation Induced Phenotypic Diversity in Dendrobium 'Emma White'

Abstract

Dendrobium, one of the largest genera of family Orchidaceae, is economically important both as an ornamental and medicinal crop. Varietal improvement of Dendrobium through the conventional breeding methods is difficult and challenging due to existence of incompatibility among the respective primary gene pool. Gamma irradiation technique is useful to induce variability and generate mutants with improved traits in a short period. In our study, protocorm-like-bodies (PLBs) of Dendrobium hybrid ‘Emma White’ were exposed to gamma rays (10-80 Gy) and in-vitro propagated up to M1V5 generation to raise irradiated plant population. Phenotypic variability was recorded among the plantlets during the ex-vitro semi-hardening stage. Leaf variations in terms of shape, size, structure, surface, tip and colour were observed in 10 Gy irradiated plants. Significant variations were observed in leaf structure and arrangement at 40 Gy. The putative mutants were analyzed for molecular characterization. Among some of the desirable mutants isolated, Mutant line 10/46 was found to exhibit early flowering. The results suggest significant potential of gamma radiation on enhancing genetic variability of both vegetative and flowering traits of Dendrobium hybrid.