Investigation of colchicine incubation time on the regeneration rate of Globba williamsiana ‘Dok Khao’

Abstract

© 2017, International Society for Horticultural Science. All rights reserved. Globba williamsiana ‘Dok Khao’ is a native ginger of Thailand. This plant has the outstanding characteristics of bract and inflorescence which have been used as an ornamental ginger for cut-flowers and potted plants. To increase the economic value of this plant, improvement is required. Chromosome doubling by colchicine is a general method for improving most plant species. Therefore, this study aimed to investigate the effect of colchicine incubation time on the regeneration rate of G. williamsiana ‘Dok Khao’ before establishing the effective protocol for producing tetraploid plants. Changing in morphological and anatomical characters of M1V1plants were also observed. After incubating young leafy-shoots, 1.5 cm high, with 0.2% (w/v) colchicine for 0, 4, 8 and 12 days, all explants were transferred to MS gelrite medium for 8 weeks. The results showed that survival rate was decreased while incubation time increased and calculated LT50was 6.9 days. The regeneration rate in term of M1V1leafy-shoot number, leafy-shoot height, root number, and root length were observed. Three from four parameters of regeneration rate, except leafy-shoot numbers of M1V1, was significantly reduced after longer exposed with colchicine. The development of leafy-shoot and leaf morphology of M1V1plants were also affected by colchicine. Changing in anatomy of some M1V1plants, such as enlargement of stomata and epidermal cell size, reduction of epidermal cell density per unit area, and disorganization of epidermal cell were observed. These morphological and anatomical characteristics may benefit for primary screening the tetraploids from diploids.