Histological characterization of wild cucumber resistance to Meloidogyne species

Using nematode resistant varieties is one of effective and environmental sound strategies being adopted in the management of economically important Meloidogyne species. Wild cucumber (Cucumis africanus) has been reported to possess resistance to Meloidogyne species. Two mechanism of nematode resistance, pre- and post-penetration resistance, had been identified, with post-penetration mechanism being used in plant breeding programs and crop rotation systems. The objective of this study was to determine the mechanism of nematode resistance in C. africanus to M. incognita and M. javanica. 6 weeks old C. africanus seedlings were separately inoculated with 100 s-stage juveniles (J2) of M. incognita and M. javanica. For 30 days, five seedlings were harvested from both M. incognita and M. javanica experiments every other day. Seedlings’ roots were examined for necrotic spots, rootlet interferences, giant cells and root gall numbers as indicators of successful or unsuccessful nematode penetration. Harvesting times were highly significant (P ≤ 0.01) on necrotic spot, rootlet interference and root gall numbers in both C. africanus—M. incognita and—M. javanica relations, but were not significant for giant cell number in C. africanus—M. incognita. The results suggested that C. africanus have post-penetration nematode resistance to both Meloidogyne species.