Polyploidy Induction of Moth Orchid (Phalaenopsis amabilis (L.) Blume) by Colchicine Treatment on Pollinated Flowers

The effectiveness of colchicine treatment at inducing polyploidy in Phalaenopsis amabilis (2n=2x=38) was investigated. Colchicine was applied on P. amabilis pollinated flowers and the development of the pods (fruit) was examined. Colchicine concentration in the experiment were 0, 50, 500, 1000, and 2000 mg L -1 , with three and five days duration. The result showed that higher colchicine concentration decreased pod length and pod number. Visual screening of the seedlings obtained from colchicines treatments were classified into normal seedlings (NS), i.e. those having similar morphology to control, and putative polyploidy mutant seedlings (PMS). All colchicine-treated PMS were significantly different compared to control in the basal organ of the protocorm (BOP) length and width, leaf length, and root length and diameter. The PMS chromosome number analysis revealed that 50 mg L -1 for three or five days colchicine application and 500 mg L -1 for five days colchicine application produced 60 and 100% tetraploid mutant seedlings, respectively.