Management of Meloidogyne incognita in nematodesusceptible watermelon cultivars using nematoderesistant Cucumis africanus and Cucumis myriocarpus rootstocks

Abstract

Watermelon (Citrullus lanatus) cultivars are highly susceptible to the southern root-knot nematode (Meloidogyne incognita), with considerable yield losses when this nematode is not managed. Empirical evidence suggested that wild watermelon (Cucumis africanus) and wild cucumber (Cucumis myriocarpus) were highly resistant to M. incognita race 2. The objective of this study was two-fold; viz. to determine whether (1) C. africanus and C. myriocarpus seedling rootstocks would be compatible with watermelon cv. ‘Congo’ and ‘Charleston Gray’ and (2) the two Cucumis spp. rootstocks would retain their nematode-resistance capabilities when grafted with the two highly nematode-susceptible watermelon cultivars. The eight treatment combinations were arranged in a randomised complete block design, with six replications. At harvest, 56 days after transplanting the grafted seedlings, with highly susceptible watermelon cultivars had no effect on nematode-resistance capabilities of C. africanus and C. myriocarpus. Also, the two Cucumis spp. were compatible with the two watermelon cultivars. Consequently, C. africanus and C. myriocarpus rootstocks have the potential for use as resistant rootstocks in the management of M. incognita race 2 in watermelon production.

Key words: Cucumis spp., root galls, resistant rootstocks, reproductive factor, watermelon cultivars.