Methods of producing 8x plants from 4x V. corymbosum clones through in vitro colchicine treatments were investigated. Colchicine concentrations and exposure times ranged from 0.001% to 0.2% and 1 to 14 days, respectively. Pretreatments designed to predispose the plants to the effect of colchicine also were investigated. Eleven 8x plants and one 4x-8x chimera were selected from pretreated plants exposed to 0.025% or 0.05% colchicine. The superior treatment was 0.025% with a 24- or 48-hr exposure time in liquid medium. No differences were noted between warm/dark and cold/dark pretreatments. No differences were observed among 24-, 48-, 96-, and 192-hr growth intervals between cold pretreatment and colchicine treatment. However, a significant genotype effect in response to colchicine was found, both with respect to culture survival and polyploid induction.
Present address: Dept. of Horticultural Science, North Carolina State Univ., Raleigh, NC 27650.
Received for publication 17 June 1983. Univ. of Florida Agricultural Experiment Station Journal Series No. 4790. The cost of publishing this paper was defrayed in pan by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.