INFLUENCE OF INOCULATION ON NODULATION AND NODULE ACTIVITY OF COWPEA VARIETIES (Vigna Unguiculata) IN PAIKO, NIGER STATE

Abstract

Cowpea response to Bradyrhizobial inoculation has been confirmed by many researchers, but not much study has been undertaken on response of cowpea to BR 3262 and BR 3267 inoculant strains in soils of Nigerian Savanna. The objective of this study was to determine the influence of Bradyrhizobium inoculation on nodulation and nodule activities of some cowpea varieties in Paiko, Niger state. Pot experiment was carried out in the screen house of the Federal University of Technology, Minna. A 2 x 4 x 4 factorial experiment was fitted to a Completely Randomized Design (CRD) and replicated three times. The treatments consisted of proximities to homestead (< 50 m close to homestead, and > 250 m far from homestead), cowpea varieties (Kanannado, IT93K-452-1, IT97K-499-35, and IT90K-277-2), and nitrogen sources (Urea (100 kg N ha-1), inoculation with Bradyrhizobium sp. (strain BR 3262 or BR 3267) and control. Most Probable Number count of the soils cultivated to cowpea varieties ranged from (9.26 - 12.27 x 106) with BR 3267 having the highest effective nodules (averagely 30 %) while the least was with the N treatment (averagely 10%). The result obtained from this study shows that cowpea could respond to Bradyrhizobial inoculation. Shoot dry weight of cowpea treated with BR 3262, BR 3267, Urea or uninoculated control indicated that the inoculant strains used for this study were highly effective. Although inoculation generally increased nodule number and nodule dry weight, however there was no corresponding increase with the urea treated plant. Proximity to homestead was not significant (p > 0.05) for the growth parameters measured in this study. The main effect of varieties was significant for all the growth parameters measured, Kanannado variety gave a better yield compared to the other varieties, while the least was IT90K-277-2. Further study should however be carried out in order to affirm this study.