The document discusses research on the effect of rhizobial inoculation on cowpea genotypes in Nigeria, focusing on nodulation, biomass, and nitrogen fixation. It aims to identify effective indigenous rhizobial strains and evaluate their effectiveness in biological nitrogen fixation. Results indicate that indigenous strains yielded higher nodule and shoot dry weights, while commercial strains were more effective for nitrogen uptake and fixation.

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Effect of Rhizobial Inoculation with Indigenous and
Commercial Strains on Nodulation, Biomass and
Nitrogen Fixation of Cowpea Genotypes in
Northern Guinea Savanna of Nigeria
By
Muhammad N. Isa1,2
, A. A. Yusuf1
N. Kamai2
and M. Dianda2
1
Department of Soil Science, Faculty of Agriculture, Ahmadu Bello University, Zaria.
2
International Institute of Tropical Agriculture, Ibadan
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INTRODUCTION
 Cowpea (Vigna unguiculata (L) Walp) is an important
vegetable and grain legume crop
 Its grain and haulm are highly valued for food and
forage
 Biological nitrogen fixation (BNF) is a cheap and
environmentally friendly source of N for plant
 High N2 fixation requires the presence of adequate
numbers of highly effective rhizobia in the soil
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OBJECTIVES
 To identify indigenous elite strain of cowpea
rhizobia
 To evaluate their symbiotic effectiveness in
Biological Nitrogen Fixation (BNF)
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MATERIALS AND METHODS
 Experimental Site
• Screen house of the IAR/ ABU, Zaria.
 Soil Sampling
• Bulk soil sample collected from IAR research field
was used for the experiments.
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MATERIALS AND METHODS
CONT.
 Screenhouse Experiment
• Five indigenous rhizobia strains SAMFIX 605,
SAMFIX 618, SAMFIX 624, SAMFIX 659 and
SAMFIX 679.
• Two commercial strains BR 3262 and BR 3267
• Two controls (uninoculated and with nitrogen
only)
• A reference crop (maize [SAMMAZ-14])
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MATERIALS AND METHODS
CONT
• The experiment was carried out on four (4)
genotypes of cowpea
I. UAM09 1051-1
II.UAM09 1055-6
III.IT99K-573-1-1
IV.IT89KD-288
• The pots were arranged in a randomized
complete block design (RCBD) with three
replications
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MATERIALS AND METHODS
CONT
 Root nodules and plant
shoot were sampled at
eight weeks after
sowing (WAS) for.
• Nodulation
• Biomass assessment
• nitrogen uptake
• biological nitrogen
fixation
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RESULT
Interaction between cowpea genotypes and rhizobium strain
on nodule dry weight
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RESULT
Interaction between cowpea genotypes and rhizobium
strain on shoot dry weight
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SE=0.960

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RESULT
Interaction between cowpea genotypes and rhizobium strain on
nitrogen uptake
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RESULT
Interaction between cowpea genotypes and rhizobium strain on
nitrogen fixation
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CONCLUSION
 The indigenous strain gave higher
• nodule dry weight with UAM09 1051-1 and
• shoot dry weight with IT89KD-288
 N uptake and BNF was highest with the
commercial strain with IT89KD-288
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Acknowledgement
 The authors express their sincere appreciation to
N2Africa/IITA for their support.
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