Growth and Yield Assessment of Sphenostylis stenocarpa Affected by Virus Infection.

African yam bean (Sphenostylis stenocarpa) 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) Infection. Telfairia mosaic virus caused severe mosaic, leaf distortion and malformation on AYB. Analyses of results revealed that TeMV caused significant (P=0.05) reduction in growth parameters of AYB; leaf area, shoot height, number of leaves produced, leaf fresh weight (FW) and dry weight (DW), relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR). Results depicted differences between healthy and infected plants with percentage reduction in leaf area, shoot height, 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% at 30 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 pod per plant, number of seed per pod, number of seed per plant, 100 seed weight. The virus caused insignificant reduction in seed length and breadth. Yield reduction due to TeMV infection in pod length of 24.7%, pod weight (40.8%), number of pod per plant (22.1%), number of seed per pod (25.6%) and number of seed per plant (40.5%). The reduction in growth and yield loses occasioned by TeMV may limit the potential of AYB from becoming an alternative food source in Nigeria.