Assessment of Cowpea (Vigna unguiculata (L.) Walp) Genotypes in Response to Rhizobium Inoculation in Makurdi, Benue State, Nigeria

Abstract

Field experiment was conducted to evaluate the performance of some selected cowpea genotypes inoculated with Rhizobium was conducted at Teaching and Research Farm of the University of Agriculture, Makurdi, Benue State, Nigeria during the 2016 rainy season. Four varieties (UAM09-1046-6-2, UAM09-1055-6, IT99K-573-1-1 and UAM14-143-4-1) were used and laid out in a Randomized Complete Block Design (RCBD) with three replications. Each variety was shared into two portions – one inoculated while the other was not inoculated. Seeds were inoculated with Rhizobium (Bradyrhizobium japonicum) by placing seeds in a plastic bowl, adding a little water to moisten, then, and adding three spoonful of sugar as adhesive. Five grams inoculant  (Bradyrhizobium japonicum) was weighed and added to  500 g of cowpea seeds, stirred and spread on aclean surface under a shade to air-dry for one hour. Seeds (inoculated and non-inoculated) were then sowed on prepared ridges at three seeds/hole at 40 cm apart. All agronomic practices were carried out. Data collected were on plant height, number of branches, days to 50% flowering, number of pods per plant, number of seeds per pod, number of nodules, and grain yield per plot. The results showed significant effect of Rhizobium inoculation on grain yield, while inoculated cowpea variety UAM09 1046-6-2 had the highest yield.