Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 16, 2011
Publication Date: April 1, 2011
Citation: Bausher, M.G. 2011. Grafting Technique to Eliminate Rootstock Suckering of Grafted Tomatoes. HortScience. 46(4):596-598. Interpretive Summary: Most of the tomato production in the Southeastern U.S. is accomplished under open field conditions and has relied on the use of fumigants, especially Methyl Bromide for the suppression of weeds and diseases. Grafting resistant rootstocks on tomatoes has been proposed as a method to reduce dependency on soil fumigation in the Southeastern U.S. However, we have found that the use of current grafting technologies can produce unintended problems particularly the regrowth of the rootstock after the grafted plants are placed in the field. This can be a serious problem because the regrowth of the rootstocks can be so vigorous that it can outgrow the top of the plant which is the area where the tomato fruit is produced. In a 2007 study the regrowth of rootstock was as high as 84.6 % for the plants in some of the test plots. By using a different grafting technique in the next year, 2008, we found that this problem was reduced to 0%, thereby eliminating the time and expense of removing the rootstock regrowth which had severely impacted yields to the extent that some fields have been abandoned.
Technical Abstract: Vegetable grafting has been proposed as a technique for avoiding disease problems in tomatoes in open field production. In this study we investigated the current use of grafting in an open field scenario and found a serious problem with the grafting techniques. In the Fall of 2007, commercially propagated tomatoes using the rootstock varieties ‘Multifort’, ‘Aloha’ and ‘TX-301’ with FL-47 scions were planted in a field experiment. The experiment consisted of four different fumigants Methyl Bromide, Paladin, Midas and an untreated control with herbicide treatment. The plots were replicated 4 times. During 5 different time periods spanning 57 days, the number of stems with bud regrowth from the rootstock occurred in all the rootstocks in the study. The number of plants with rootstock regrowth was as high as 84.6 % in some of the plots for ‘Multifort’, with ‘Aloha’ at 30.7 % and ‘TX-301’ at 15.4 %. Even when the rootstock regrowth was removed these areas would regrow. The statistical interaction of the rootstocks for all dates the data was recorded was significant for ‘Multifort’ (Tukey-Fischer P= 0.05) but not ‘Aloha’ nor TX-301. There was no significant regrowth interaction for any of the soil treatments. In 2008 we repeated the same experiments but grafted the plants below the rootstock cotyledons (hypocotyl area) and observed no regrowth from the rootstocks. Since adopting this method we have not observed any rootstock regrowth in subsequent field experiments.