African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6691

Full Length Research Paper

Yam (Dioscorea spp.) responses to the environmental variability in the Guinea Sudan zone of Benin

Afio Zannou*
  • Afio Zannou*
  • Faculté des Sciences Agronomiques, Université d’Abomey-Calavi, Bénin.
  • Google Scholar
Paul Struik
  • Paul Struik
  • Centre for Crop Systems Analysis, Wageningen University, The Netherlands.
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Paul Richards
  • Paul Richards
  • Technology and Agrarian Development, Wageningen University, The Netherlands.
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Jeanne Zoundjihékpon
  • Jeanne Zoundjihékpon
  • Faculté des Sciences et Techniques, Université d’Abomey-Calavi, Bénin.
  • Google Scholar


  •  Received: 17 October 2013
  •  Accepted: 28 May 2015
  •  Published: 31 December 2015

Abstract

This study analyzed the morphological characteristics and agronomic potentials of yam varieties (Dioscorea spp.) collected across the Guinea Sudan transition zone of Benin. Dioscorea cayenensis - D. rotundata varieties were characterized as wingless; some varieties were spineless, others had few or dense, robust or thin, and short or prickled spines. There was variation in leaf shape, stem and leaf colour, tuber shapes and forking tendencies. The tuber flesh presented different colours, texture, oxidation colour, oxidation time, and ability to irritate. Dioscorea alata varieties were all spineless and showed winged stems, pentagonal or quadrangular. Various leaf and petiole colours, and tuber shapes were observed. On average, the mean Shannon-Weaver index was 0.86 for the external morphology of the tuber, 0.55 for tuber flesh characteristics, and 1.13 for stem and leaf morphology. The pooled mean yield varied between 0.89 and 3.30 kg/heap for the early maturing varieties of the D. cayenensis - D. rotundata, between 0.94 and 3.03 kg/heap for the late varieties, and ranged from 1.45 to 4.17 kg/heap for the D. alata varieties. The year effect was highly significant for variety-type group and species, and was larger than the genotypic effect. The genotype by year interaction effects were highly significant. 
 
Key words: Dioscorea spp., genotype by environment interaction, yield, yam varieties’ traits, Benin.