Determination of ploidy level by flow cytometry and autopolyploid induction in cocoyam (<i>Xanthosoma sagittifolium</i>)

Abstract

A procedure for chromosome doubling of the white cocoyam (Xanthosoma sagittifolium) type was established by using colchicine and oryzalin treatments to in vitro plantlets. Flow cytometry was successfully used for analyzing ploidy levels within three cocoyam types and regenerated plants. Treating in vitro white cocoyam with 0.05% colchicine for 7 days produced tetraploids. The oryzalin treatment (0.05% for 3 days) produced only mixoploids, but it has in turn, a lower rate of mortality. Therefore, in white cocoyam, oryzalin could constitute an alternative to the use of colchicine, whenever the selection and stabilization of polyploids induced by this reagent will be achieved.

Key words: colchicine, oryzalin, flo w cytometry, ploidy level, tetraploid, mixoploid, cocoyam (Xanthosomasagittifolium).