Characterization of a mutant population of cocoyam (Xanthosoma sagittifolium L. Schott)

Abstract

A mutant population of cocoyam (Xanthosoma sagittifolium L. Schott) developed through gamma irradiation of shoot tips of cocoyam was evaluated in two field experiments. In the first experiment, four putative mutants, fifty irradiated clones and four non-irradiated clones were evaluated for morpho-agronomic diversity. Progeny derived from minisetts were characterised in a second experiment to establish repeatability of the distinctive characters of the putative mutants. Yields were exceptionally low and this was attributed to poor environmental conditions. The mutants showed a distinctive yellow cormel apex and yellow interior cormel colour. Out of seventeen morphological traits studied in the second experiment, ten were monomorphic. These were growth habit, petiole attachment, petiole surface glaucous, leaf pubescence, leaf variegation, leaf surface glossy (shining), leaf margin, number of collecting vein, position of collecting vein and shape of petiole in cross-section. The seven polymorphic traits were petiole colour, colour of vein on leaf surface, leaf shape, leaf margin colour, leaf surface colour, leaf sinus denuding and lamina orientation. The main differences in the polymorphic characters were between the mutants on one side and the irradiated (non mutants) and non-irradiated clones on another side. It will be interesting to determine whether the mutants have desirable agronomic characters. © 2006 Asian Network for Scientific Information.