Serotypes and prevalence of legume viruses in Niger State, Southern Guinea Savanna of Nigeria

Abstract

Field survey was conducted between September and October, 2015 to determine the serotypes and prevalence of legume viruses in Niger State, Southern Guinea Savanna of Nigeria. Niger State has 25 Local Government Areas (LGAs), grouped into three Agricultural zones. A multi-stage sampling procedure was employed to select three LGAs from each of the three zones, giving a total of 9 LGAs. Three villages/locations from the nine LGAs were randomly selected for the survey to give a total of 27 locations. Leaves were collected from cultivated cowpeas, groundnuts and soybean farms. Weeds showing virus and virus-like symptoms were also collected. The samples were preserved over silica gels in vial bottles and tested against major legume viruses [Blackeye cowpea mosaic virus (BlCMV), Cowpea aphid-borne mosaic virus (CABMV), Cowpea mild mottle virus (CPMMV), Cowpea yellow mosaic virus (CPMV), Cucumber mosaic virus (CMV), Cowpea mottle virus (CPMoV) and Southern bean mosaic virus (SBMV)], using Antigen Coated Plate - Enzyme linked immunosorbent assay (ACP –ELISA). In all, 14.8 % of the total samples tested positive for BlCMV, which was detected in Dabiri, Farin Shinge, Gidan Kwano and Tatiko. CPMMV was detected in Farin Shinge and Manigi, which accounted for 7.4 % of the total locations. In addition, CPMoV was found in Awuru, Gidan Kwano, Lemu, Manigi and Tatiko, which accounted for 18.5 % of the locations, whereas samples from other locations showed negative reaction. ELISA positive samples were detected in cowpea, groundnut, soybean and weeds (Aeschynomene indica, Hyptis suaveolus, and Euphorbia hirta). The occurrence of CPMoV and CPMMV in naturally infected legumes is believed to be the first report from Niger State. Inocula of the identified viruses could be utilized for breeding resistant cowpea, groundnut and soybean cultivars.