To identify indigenous elite strain of cowpea rhizobia and to evaluate their symbiotic effectiveness in Biological Nitrogen Fixation (BNF).

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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
1Department of Soil Science, Faculty of Agriculture, Ahmadu Bello University, Zaria.
2International 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
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
1.000
SAMFIX605 SAMFIX618 SAMFIX624 SAMFIX659 SAMFIX679 BR3262 BR3267 CONTROL MINERALN
noduledryweight(g)/plant
rhizobium strain
UAM09 1051-1
UAM09 1055-6
IT99K-573-1-1
IT89KD-288
SE=0.0703
Interaction between cowpea genotypes and rhizobium strain
on nodule dry weight
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RESULT
0.00
5.00
10.00
15.00
20.00
25.00
30.00
SAMFIX605 SAMFIX618 SAMFIX624 SAMFIX659 SAMFIX679 BR3262 BR3267 CONTROL MINERALN
shootdryweight(g)/plant
rhizobium strain
UAM09 1051-1
UAM09 1055-6
IT99K-573-1-1
IT89KD-288
Interaction between cowpea genotypes and rhizobium
strain on shoot dry weight
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SE=0.960

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RESULT
0.00
100.00
200.00
300.00
400.00
500.00
600.00
700.00
SAMFIX605 SAMFIX618 SAMFIX624 SAMFIX659 SAMFIX679 BR3262 BR3267 CONTROL
Nuptake(mg)/plant
Rhizobium Strain
UAM09 1051-1
UAM09 1055-6
IT99K-573-1-1
IT89KD-288
SE=43.003
Interaction between cowpea genotypes and rhizobium strain on
nitrogen uptake
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RESULT
0.00
100.00
200.00
300.00
400.00
500.00
600.00
SAMFIX605 SAMFIX618 SAMFIX624 SAMFIX659 SAMFIX679 BR3262 BR3267 CONTROL
Nitrogenfixation(mg)/plant
RhizobiumStrain
UAM09 1051-1
UAM09 1055-6
IT99K-573-1-1
IT89KD-288
SE=40.403
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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