Varietal response of African yam bean, Sphenostylis stenocarpa (Hochst Ex. A. Rich) Harms to infection with Meloidogyne incognita (Kofoid & White) Chitwood under field conditions

Abstract

A pot study demonstrated that four and eight African yam bean (Sphenostylis stenocarpa) accessions were tolerant and susceptible to the root-knot nematode (Meloidogyne incognita), respectively. A study was, therefore, conducted to confirm the pot results under field conditions. Experimental design was randomized complete block design with 3 replications. A total of 750 nematode juveniles per 500 g soil sample from experimental field were recorded as the pre-planting initial nematode population. Data were collected on growth, yield and yield parameters of the different African yam bean accessions and statistically analyzed using Genstat for windows, version 3.2. Results indicated that none of the accessions was resistant to M. incognita infection as most of the sampled parameters were significantly (P≤0.05) reduced by M. incognita infection. Percentage yield losses amongst the accessions ranged from 6.2 to 71.5%. Four accessions, TSS 63, Eha-Amufu, TSS 56 and Ugbokolo were categorized as tolerant, while TSS 3, TSS 4, TSS 22, TSS 5, TSS 10, TSS 11, TSS 112 and TSS 7 were susceptible. In conclusion, results of this study confirmed those under pot conditions. The tolerant accessions are, therefore, recommended for use by farmers to minimize losses due to M. incognitainfection. Key words: African yam bean, Meloidogyne incognita, infestation, field condition.