African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12258

Full Length Research Paper

Somatic polyploidization and characterization of induced polyploids of Dioscorea rotundata and Dioscorea cayenensis

Pachakkil Babil*
  • Pachakkil Babil*
  • Department of International Agricultural Development, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan.
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Midori Iino
  • Midori Iino
  • Graduate School of Agricultural Sciences, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan.
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Yukiko Kashihara
  • Yukiko Kashihara
  • International Institute of Tropical Agriculture, Ibadan, Oyo State, Nigeria.
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Ryo Matsumoto
  • Ryo Matsumoto
  • Japan International Research Center for Agricultural Sciences, 1-1 Ohwashi, Tsukuba 305-8686, Japan.
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Hidehiko Kikuno
  • Hidehiko Kikuno
  • Department of International Agricultural Development, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan.
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Antonio Lopez-Montes
  • Antonio Lopez-Montes
  • International Institute of Tropical Agriculture, Ibadan, Oyo State, Nigeria.
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Hironobu Shiwachi
  • Hironobu Shiwachi
  • Department of International Agricultural Development, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan.
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  •  Received: 23 July 2016
  •  Accepted: 26 August 2016
  •  Published: 21 September 2016

Abstract

Genetic improvement of major food yams is constrained by a number of factors, such as the scarcity of flowers and lack of synchronization between male and female flowering. Consequently, somaclonal variation including somatic polyploidization has been considered as a useful tool in yam breeding. Somatic polyploidization and its effect on phenotypic traits of Dioscorea species such as D. alata, D. japonica and D. zingiberensis has been reported; however, optimization of this method in two major yam species, D. rotundata and D. cayenensis, is yet to be achieved and the effect of polyploidization on phenotypic traits of this species yet to be elucidated. In the present study, a high rate of somaclonal polyploid variation was successfully achieved by in vitro colchicine treatment of D. rotundata and D. cayenensis. In most cases, except TDc 3704, the highest rate of polyploid induction appeared after 0.1% colchicine treatment. However, in triploid yellow yam accessions the induction rate was relatively low. Tetraploid variants of D. rotundata tended to display somewhat rounder leaves than their diploid parents. The size and shape of D. rotundata stoma were also affected by levels of ploidy, with tetraploid variants exhibiting larger stomata at a lower density compared to their diploid parents. The efficient method of in vitro polyploidy induction reported here is therefore a highly useful tool for obtaining polyploid variants for use as genetic resources in D. rotundata breeding.

Key words: Leaf, nodal segment culture, ploidy level, somaclonal variation, stoma, white guinea yam, yellow Guinea yam.