Abstract

Watermelon (Citrullus lanatus) cultivars suffer considerable yield losses from infection by the root-knot nematodes due to the unavailability of nematode-resistant genotypes. Screening for nematode resistance within the family Cucurbitaceae demonstrated that wild watermelon (Cucumis africanus) and wild cucumber (C. myriocarpus) were highly resistant to Meloidogyne incognita races 2 and 4 and M. javanica, with both nematode species being widely distributed in watermelon-producing regions of South Africa. However, Citrullus-Cucumis grafts had at least 64% mortalities, with the surviving inter-grafts displaying poor growth when compared with Citrullus intra-grafts. The paper reviews inter-generic grafting challenges in Citrullus cultivars and outlines uses of Cucumis grafts as novel solution that could probably be extended to other inter-generic grafts in the management of plant-parasitic nematodes.

Key words: Citrullus lanatus, Cucumis africanus, Cucumis myriocarpus, inter-generic grafting, Meloidogyne species, watermelon.