Growth and yield assessment of Sphenostylis stenocarpa affected by virus infection

African yam bean (Sphenostylis stenocarpa (Hoechst ex. A. Rich.) Harms. is an underexploited legume with the potential of becoming an alternative food staple to alleviate the problem of food security. An assessment was carried out on the growth and yield of AYB affected by Telfairia mosaic virus (TeMV). Telfairia mosaic virus caused severe mosaic, leaf distortion, and malformation on AYB. Seeds of AYB were cultivated and on germination, inoculated with TeMV and the virus effect at different stages of growth and yield was measured. Results analyses revealed that TeMV caused significant (P=0.05) reduction in growth parameters of AYB including leaf area, shoot height, number of primary shoot branches, number of leaves produced, leaf fresh weight (FW) and dry weight (DW), relative growth rate (RGR), net assimilation rate (NAR), and leaf area ratio (LAR). Results depicted differences between healthy and infected plants with percentage reduction in leaf area, shoot height, and leaf fresh and dry weight at 120 DAI of 41.5%, 48.4%, 29.6%, and 25.5% respectively. Relative growth rate, NAR had reductions of 27.2%, 39.1% 30 days after inoculation (DAI) and 27.0% for LAR at 120 DAI. Infection also led to significant (P=0.05) yield loses: reduction in pod length, pod width, pod weight, number of pods per plant, number of seeds per pod, number of seeds per plant, 100 seed weight. The virus caused insignificant reduction in seed length and breadth, with significant reduction in pod length of 24.7%, pod weight (40.8%), number of pods per plant (22.1%), number of seeds per pod (25.6%), and number of seeds per plant (40.5%). Telfairia mosaic virus caused reduction in growth and yield which may limit the potential of AYB in becoming an alternative food source in Nigeria.