2012 Annual Report
1a.Objectives (from AD-416):
Identify effective rootstocks for managing Fusarium wilt and root-knot nematodes in grafted specialty melon production in the Southeastern U.S.
1b.Approach (from AD-416):
Commercial rootstocks, wild germplasm, and elite cultivars of bottle gourd (Lagenaria siceraria), hybrid squash (Cucumis moschata x C. maxima), winter melon (Benincasa hispida), Cucumis metulifer, Cucumis ficifolia, and cantaloupe (Cucumis melo) will be evaluated for resistances to Fusarium wilt (Fusarium oxysporum f. sp. melonis) and southern root-knot nematode (Meloidogyne incognita) and for graft compatibility with melon in greenhouse tests in SC. The five most resistant and graft-compatible genotypes will be evaluated as rootstocks for two desirable melon cultivars (scions) in fields infested with F. oxysporum f. sp. melonis and M. incognita in Charleston, SC. Vine vigor, incidence and severity of Fusarium wilt, and severity of root galling caused by root-knot nematode will be rated, and fruit yield will be recorded.
This project corresponds with the inhouse Objective 2: Determine genetic basis of resistance to root-knot nematodes in watermelon, identify molecular markers associated with resistance, and develop resistant breeding lines.
Ten selected Cucumis metuliferus (African-horned cucumber) rootstocks were evaluated for compatibility with the scion ‘Athena’ melon in field trials in Charleston, SC. A number of these rootstocks were highly compatible with melon. Greenhouse studies were conducted to evaluate response of selected cucurbit lines against southern root-knot nematode (Meloidogyne incognita) in order to identify additional potential resistant rootstocks (RKN) for grafted melon. Compatible melon scion and root-knot nematode resistant rootstock (RKN) combinations will be useful for managing RKN in susceptible speciality melons in nematode-infested fields in the Southeastern U.S. Fifteen commercially available rootstocks used in cantaloupe grafting were screened for their reaction to the Fusarium wilt pathogen. The majority of these rootstocks were found to have non-host resistance to both race 1 and race 2 of this fungal pathogen. In addition, several experimental rootstock lines of Cucumis metuliferus were also screened following infection by race 1 and 2 and all were found to have non-host resistance. The use of non-host resistance should work well in grafted cantaloupe for protection against Fusarium wilt.