Assessment of The Abundance and Effectiveness of Cowpea [Vigna unguiculata (L) Walp] Rhizobia in Soils from Different Fields in Chiwosya Extension Planning Area, Mchinji District

Submitted by charlotte.schilt on

A study was conducted in 2013 at Chitedze Agricultural Research Station to assess the abundance and effectiveness of cowpea rhizobia in soils from different fields and their nodulation capacity by different cowpea genotypes using native cowpea strains. The soils from four fields (Groundnut, Cowpea, Maize and Virgin/non cropped) were used as inoculums including Malawi cowpea inoculant and Australian cowpea inoculant and no inoculation in experiment 1. Highly significant differences (P=0.001) in Rhizobium numbers were observed among the fields. The inoculums from cowpea field and virgin land gave higher Rhizobium numbers (342 and 217 cfu/g of soil respectively) such that nodulation capacity was higher in plants inoculated with inoculums from cowpea field and virgin land. There significant differences in colony growth, reaction to bromothymol blue and reaction on congo red (P=0.03 P=0.001 and P=0.001 respectively) such that five presumptive strains (CZS1, CZS2, CZS3, CZS4, CZS5) were selected from cowpea field and virgin land including MG5013 (check) were evaluated with the following cowpea genotypes; IT00K-126-3 and IT97K-390-2, Sudan-1, IT82E-16 and Mkanakaufiti in a factorial experiment. There was significant interaction on nodule color and plant nitrogen content (P=0.009 and P=0.001 respectively). Genotype IT00K-126-3 was compatible with CZS2 and Mkanakaufiti and Sudan-1 were compatible with CZS4 since had nodules with dark pink color and gave 4.8% and 3.6% plant N content respectively. This means CZS2 and CZS4 can be considered for production of inoculant for specific cowpea genotypes/varieties.


MSc and Bcs thesis, internship reports

Esnart Nyirenda Yohane