|GUAN, WENJING - University Of Florida|
|ZHAO, XIN - University Of Florida|
|DICKSON, DONALD - University Of Florida|
|MENDES, MARIA - University Of Florida|
Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/14/2014
Publication Date: 8/1/2014
Citation: Guan, W., Zhao, X., Dickson, D.W., Mendes, M.L., Thies, J.A. 2014. Root-knot nematode resistance, yield, and fruit quality of specialty melons grafted onto Cucumis metulifer. HortScience. 49:1046-1051.
Interpretive Summary: In recent years there has been increasing demand by United States consumers for specialty type melons, like the Galia, ananas, Persian, canary and Crenshaw types. A plant pathogen called root knot nematodes can readily infect the roots of most melons produced in southern states, resulting in significant crop and economic losses for growers. Most of the specialty melons are very susceptible to root knot nematodes; thus, there is a need to find ways to limit the infections and damage caused by these pests to minimize monetary losses incurred by melon growers. In light of this, an ARS scientist collaborated with scientists from the University of Florida to determine if damage to specialty melons could be reduced by grafting them to root stocks of wild cucumber plants that are highly resistant to the nematodes. Results of their studies showed that specialty melons grafted to wild cucumber plants exhibited fewer signs of nematode infection, but they did not yield more melons than plants that were not grafted to resistant root stocks. Although use of the grafted plants did not translate to better yields, the scientists concluded that use of the resistant rootstocks may effectively lower nematode populations in the soil and help crops that are grown after the grafted crop. These results are of interest to other scientists in the public and private sector, as well as extension personnel working to employ resistant rootstocks in vegetable production systems.
Technical Abstract: Interest in specialty melons (Cucumis melo) with distinctive fruit characteristics has grown in the United States in recent years. However, disease management remains a major challenge in specialty melon production. In this study, grafting experiments were conducted to determine the effectiveness of using Cucumis metulifer, a species known for its genetic resistance to root-knot nematodes (RKNs; Meloidogyne spp.), as a potential rootstock for managing RKNs in susceptible specialty melon cultivars. In the greenhouse experiment, honeydew melon ‘Honey Yellow’ was grafted onto C. metulifer and inoculated with M. incognita race 1. The grafted plants exhibited significantly lower gall and egg mass indices and fewer eggs compared with non- and self-grafted ‘Honey Yellow’. Cucumis metulifer was further tested as a rootstock in conventional and organic field trials using honeydew melon ‘Honey Yellow’ and galia melon ‘Arava’ as scions. ‘Honey Yellow’ and ‘Arava’ grafted onto C. metulifer exhibited significantly lower galling and reduced RKN population densities in the organic field; however, total and marketable fruit yields were not significantly different from non- and self-grafted plants. Although the improvement of RKN resistance did not translate into yield enhancements, incorporating grafted specialty melons with C. metulifer rootstock into double-cropping systems with RKN-susceptible vegetables may benefit the overall crop production by reducing RKN population densities in the soil. At the conventional field site, which was not infested with RKNs, ‘Honey Yellow’ grafted onto C. metulifer rootstock had a significantly lower total fruit yield than non-grafted ‘Honey Yellow’ plants; however, fruit yields were similar for ‘Arava’ grafted onto C. metulifer rootstock and non-grafted ‘Arava’ plants. Although no significant impacts on the fruit quality attributes of ‘Honey Yellow’ were observed, grafting onto C. metulifer decreased the flesh firmness of ‘Arava’ in both field trials and resulted in a reduction in total soluble solids content under conventional production. In summary, grafting RKN-susceptible melons onto C. metulifer rootstock offers promise for growing these specialty melons; however, more studies are needed to elucidate the scion–rootstock interaction effect on fruit yield and quality.