Growth and yield of grafted watermelon in Meloidogyne incognita (Tylenchida: Heteroderidae) infested soil

The objective of this study was to evaluate the growth, yield and tolerance of grafted watermelon against parasitic Meloidogyne incognita. Watermelon (Citrullus lanatus cv. "Cal sweet") was grafted on regional creole rootstocks: 1) Lagenaria siceraria; 2) Cucurbita moschata; 3) Cucumis melo 4) Cucumis sativus and 5) Citrullus lanatus cv. "Cal sweet" ungrafted (control). The experiment was established under open field conditions in the 2019 autumn-winter season. The experimental design was randomized complete blocks, each treatment consisted of 25 plants as experimental unit. Agronomic variables, yield, and tolerance to nematodes were evaluated. The grafted plants flowered eight days earlier and presented higher growth yield (18.5 t ha-1) and fruit size up to 18 % compared to the control. The watermelon grafted on the rootstocks of L. siceraria and C. moschata obtained the lowest galling index (11 and 25 % respectively), number of eggs per gram of root (544 and 753 respectively) and number of fema- les per gram of dyed root (12 and 22 respectively) compared to the control. The study showed that growth, flowering and yield of grafted plants were significantly influenced by the rootstocks despite the presence of nematodes.