IMPROVING PRODUCTIVITY OF CITRULLUS LANATUS SUBSP MUCOSOSPERMUS (EGUSI MELON) THROUGH IDENTIFICATION AND USE OF LOCAL NEMATODE RESISTANT VARIETIES

Abstract

Citrullus lanatus subsp. mucosospermus F. (egusi melon, Cucurbitaceae) is a traditional fruit vegetable with important nutritional, economic and socio-cultural values in West Africa. However, root-knot nematodes (Meloidogyne spp.) are a major production constraint, and a reason for drastic reduction of the egusi melon cultivated areas. To develop strategies for sustainable root-knot nematode management in egusi melon production systems, eight egusi landraces from Benin were assessed for resistance or tolerance to root-knot nematodes in naturally infested fields. Results indicated that responses to root-knot nematode attacks differ significantly among egusi landraces. The egusi landrace BEN 1-3-7 showed the greatest potential in nematode suppression with a final nematode population density of 236 nematodes per 25 g roots. In contrast, the landrace BEN 1-5-13 had the highest final nematode population density (13929 nematodes / 25 g root), with the highest average hulled grain yield (528 kg/ha), suggesting a good tolerance of this landrace to root-knot nematodes. Root galling varied significantly between egusi landraces, with an average gall index of 3.25 over 10. Correlation analysis indicated, in some cases, a negative correlation between galling index and seed weight, and between nematode densities and seed weight. The results provide evidence of genetic variability among West African landraces of egusi melon for reaction to root-knot nematodes.