African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6577

Full Length Research Paper

Preliminary screening of cowpea-Bradyrhizobium symbiotic traits subjected to salinity stress in Senegal

Abdoulaye Soumare
  • Abdoulaye Soumare
  • Département de Biologie Végétale, Faculté des Sciences et Techniques, Université Cheikh Anta DIOP de Dakar, Sénégal.
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Mbaye Wade
  • Mbaye Wade
  • Département de Biologie Végétale, Faculté des Sciences et Techniques, Université Cheikh Anta DIOP de Dakar, Sénégal.
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Francis Do Rego
  • Francis Do Rego
  • Institut de Recherche pour le Développement (IRD), UMR 113-LSTM, Laboratoire Commun de Microbiologie IRD/ISRA/UCAD, Centre de Recherche de Bel Air, BP1386, CP 18524 Dakar, Sénégal.
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Saliou Fall
  • Saliou Fall
  • Institut Sénégalais de Recherches Agricoles, Laboratoire National de Recherche pour les Productions Végétales, Laboratoire Commun de Microbiologie (LCM, IRD/ISRA/UCAD), Centre de Recherche de Bel Air, Route des hydrocarbures, BP 3120 Dakar, Sénégal.
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Tatiana Krasova Wade
  • Tatiana Krasova Wade
  • Institut de Recherche pour le Développement (IRD), UMR 113-LSTM, Laboratoire Commun de Microbiologie IRD/ISRA/UCAD, Centre de Recherche de Bel Air, BP1386, CP 18524 Dakar, Sénégal.
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  •  Received: 15 August 2017
  •  Accepted: 21 September 2017
  •  Published: 09 November 2017

Abstract

Cowpea (Vigna unguiculata L. Walp) is a leguminous plant which is an important source of protein, grown in arid and semi-arid areas of Africa subject to climate changes including soil salinization. The current study aimed to test the hypothesis that screening for salt-tolerant Bradyrhizobim-cowpea combination would promise a salt tolerant symbiotic system. Four selected Bradyrhizobium were characterized for their abilities to grow freely in salt medium and for their symbiotic efficiency in improving cowpea growth in Leonard jars at 3 levels of salinity (0, 40 and 80 mM). The effectiveness of inoculated bacteria was assessed by measuring shoot and root dry matters, salt tolerance index, leaf chlorophyll content and leaf area. This study did not show a correlation between strains tolerance to high salt concentrations in free-living form and symbiotic efficiency on cowpea. Furthermore, results showed that all the strain improved root/shoot ratio (RSR) and yield of cowpea plants up to 40 mM. However at 80 mM, only LCM4767 and ORS3257 strains were efficient. Selected strains improved and/or maintained plant growth and production under salt stress. The results suggest that cowpea production can be improved by introduction of efficient legume-Bradyrhizobium symbiotic combinations in saline areas.

 

Key words: Salt stress-tolerance, Bradyrhizobium, cowpea, symbiosis, Senegal.