Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: February 17, 2007
Publication Date: June 1, 2007
Citation: LaMolinarel, B.M., Isakeit, T.W., Davis, A.R., Liu, W.Z., King, S.R. 2007. Adding value to grafted watermelon: Novel benefits and potential pitfalls [abstract]. HortScience. 42(3):454.
Grafted watermelons are commonly used in Asia and areas of Europe but are not widely used in the United States. The traditional reason for grafting watermelons has been for resistance to soil borne diseases such as Fusarium. We began to explore novel benefits which might make grafted watermelons more economical for producers in the US. Cold tolerance and the possible transmission of desirable transgenic traits from the rootstock to the scion were two areas of investigation. We also examined the potential for rootstocks to transmit watermelon fruit blotch to the scion. Increased cold tolerance was observed when a selected rootstock breeding line was grafted to 'Ole.' Plants were placed in a cold chamber at 5C for 7 days. Both the un-grafted rootstock and grafted 'Ole' showed fewer signs of physical temperature stress compared to un-grafted 'Ole.' The use of transgenic rootstock to transmit desirable traits to the scion was investigated using transgenic virus resistant squash. Watermelon, melon and cucumber were grafted onto the transgenic squash, and leaf samples were analyzed to determine if RNA from the transgene was present in scion leaves. The final area of investigation studied the possibility of transmitting watermelon fruit blotch (wpd) from infected rootstocks to watermelon scions. Rootstocks of Lagenaria siceraria, Cucurbita maxima and C. moschata were inoculated with Acidovorax avenae and incubated for 3 d under high humidity. All potential rootstocks showed typical water-soaking symptoms of WFB. A. avenae was found to move within the stem of all 3 species, indicating a probability for transmission of the pathogen from the rootstock to the scion. Future experiments will investigate the potential for A. avenae to become seed-borne on rootstocks.