ARS | Publication request: Grafting for Management of Root-Knot Nematodes in Watermelon

Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: February 10, 2009
Publication Date: June 1, 2009
Citation: Thies, J.A., Ariss, J., Hassell, R., Olson, S. 2009. Grafting for Management of Root-Knot Nematodes in Watermelon. HortScience. 44(3):576.

Technical Abstract: Five wild watermelon (Citrullus lanatus var. citroides) germplasm lines, four bottlegourd (Lagenaria siceraria) cultivars, one squash (Cucurbita moschata x C. maxima) hybrid, and one commercial wild watermelon (C. lanatus spp.) cultivar were evaluated as rootstocks for watermelon in a field infested with the southern root-knot nematode, Meloidogyne incognita, in Charleston, SC in 2007 and 2008. Rootstocks were grafted to the scion diploid watermelon (C. lanatus var. lanatus) ‘Fiesta’ in 2007 and to the scion triploid watermelon ‘Tri-X 313’ in 2008. In 2007, four C. lanatus var. citroides germplasm lines and the commercial wild watermelon rootstock had significantly less (P<0.05) root galling than non-grafted ‘Fiesta’ watermelon, the L. siceraria rootstocks, and the C. moschata x C. maxima hybrid rootstock. In 2008, three C. lanatus var. citroides germplasm lines had significantly less root (P<0.05) galling than non-grafted ‘Tri-X 313’ watermelon, the L. siceraria rootstocks, and the C. moschata x C. maxima hybrid rootstock. The L. siceraria rootstock and the C. moschata x C. maxima hybrid rootstock exhibited severe root galling in both years (80 to 96% in 2007 and 96 to 100% in 2008). Root galling was moderately severe for non-grafted ‘Fiesta’ (40%) and ‘Tri-X 313’ (56%) watermelon. The commercial wild watermelon rootstock had 24 and 39% root galling in 2007 and 2008, respectively. Root galling for germplasm lines derived from C. lanatus var. citroides ranged from 11 to 34% and 32 to 42% in 2007 and 2008, respectively. Citrullus lanatus var. citroides germplasm lines may provide a source of resistance that will be useful in developing root-knot nematode resistant rootstocks for watermelon.