Host-Parasite Relationship Between African Yam Bean, Sphenostylis stenocarpa (Hochst. Ex. A. Rich) Harms Accessions and Meloidogyne incognita (Kofoid & White) Chitwood I.

Abstract

Experiments were carried out in both pots and field to investigate compatibility or incompatibility reactions between M. incognita and 12 accessions of the African yam bean, S. stenocarpa (Hochst. Ex.A. Rich) Harms. The 12 African yam bean accessions were TSS 3, TSS 63, TSS 4, TSS 22, TSS 5, Eha-Amufu, TSS 10, TSS 56, TSS 11, TSS 112, Ugbokolo and TSS 7. The mean number of nematodes in roots of the African yam bean accessions was determined at the intervals of 10 days till the 100th day and was used as indication for compatibility or incompatibility. Inoculated plants in the pots received 4,000 eggs of M. incognita while the field was confirmed to be infested with inoculum level of about 75 nematode larvae per 50 cm³ of soil sample. Results showed that all the suggested susceptible accessions demonstrated the highest degree of penetration and post-penetration compatibility since they had the highest number of M. incognita at both stages. The suggested tolerant accessions reacted otherwise as they had the least number of nematodes at both penetration and post-penetration stages. The highest over all mean number of nematodes was isolated at 100 days after infection while the least over all mean number of nematodes was isolated at 10/20 days after inoculation/planting.

Keywords: African yam bean, M. incognita, host-parasite relationship