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Since the 1970s, U.S. growers have relied upon methyl bromide soil fumigation to control soil-borne pests in high value, fresh market, vegetable production systems. For example, fresh market tomato growers are the principal users of methyl bromide in the U.S., accounting for 24% of the national pre-plant consumption (EPA, 2006). Major challenges to identifying methyl bromide alternatives include the additional costs of alternatives, lower yield, delays in planting, limited spectrum of activity against soil-borne pests and issues relating to worker protection. Finding alternatives and partial alternatives to methyl bromide for pre-plant applications and their technical and economic feasibility based on commercial scale trials is critical to the complete transition to alternatives in the U.S. <P>The goal of this project is to demonstrate the potential of grafting technology as a partial replacement of methyl bromide currently used in pre-plant soil for tomato and cucurbits, and to facilitate the transfer of research and technical information to the stakeholders, academic researchers and extension personnel in order to promote the introduction of this technology.<P> Our specific objectives of the 3-year project are:<ol> <LI> To evaluate muskmelon and tomato rootstock varieties for resistance to root knot nematode and other soil-borne diseases and overall horticultural performance under controlled experimental settings in Arizona and Florida. <LI> To evaluate both agronomic field performance and economic viability of grafted muskmelon and tomato seedlings in commercial fields in Arizona and Florida.<LI> To develop short term storage technique for grafted muskmelon seedlings. <LI> To develop an information website on grafted seedling technology and use. </ol>Our project will focus on tomato and muskmelon as model crops, but the application of grafting is not limited to these species. Demonstration through the field trials and the information acquired on use of grafted seedlings in tomato and muskmelon from our project can promote the same methodology for other common vegetable crops such as watermelon, eggplant, and cucumber in the future.
Non-Technical Summary: Use of grafting in open-field fresh vegetable production is an important alternative technology to methyl bromide used to control soil-borne pests in many countries, but is not widely practiced in the U.S. Our research will demonstrate the potential of grafting technology as a partial replacement of methyl bromide currently used in pre-plant soil for tomato and cucurbits, and to facilitate the transfer of research and technical information to the stakeholders, academic researchers and extension personnel in order to promote the introduction of this technology to adopt grafting in U.S. open-field production. <P> Approach: 1) Evaluation of muskmelon and tomato rootstock varieties for resistance to root-knot nematode and other soil-borne diseases and overall horticultural performance. Much of the information on the efficacy of rootstock and grafted plants for pathogen and nematode control was obtained outside the U.S. Therefore we will re-evaluate rootstock varieties available from seed companies and as well as new potential rootstock species using a pest nursery field and greenhouse in Florida and greenhouses in Arizona. Specifically, we will focus on collecting data on tomato and muskmelon rootstock performance and resistance to pathogen infection using a pest nursery field at the USDA Picos Road Farm in Fort Pierce, FL. Also, experiments will be conducted in greenhouses to test the performance of the rootstocks under greenhouse conditions. Another concurrent study in Arizona will focus on a greenhouse based controlled experiment, testing tomato and muskmelon rootstocks for potential resistance and tolerance to root-knot nematode (Meloidogyne spp.) at varied root-zone temperatures. 2) Evaluation of both agronomic field performance and economic viability of grafted muskmelon and tomato seedlings in commercial fields. Commercial field trials will be conducted to collect data and demonstrate the value of grafted seedlings, including such benefits as pests and disease resistances, increased yield and quality improvement of muskmelon and tomato. The field trials are planned in Harquahala, AZ for muskmelon and in southeastern FL for tomato. Local growers will collaborate on a contract basis to provide field trials with sufficient land and all aspects of crop production, including tillage, planting, fertilization, irrigation, pest control, and harvest. A commercial propagator will be contracted to supply seedlings grafted to the selected rootstocks. Economic analysis will quantify the long-term economic viability of grafted seedlings using commercial scale practices. 3) Development of short term storage technique for grafted muskmelon seedlings. Capability of short term storage of vegetable seedlings is important to distribute over time the production of large number of seedlings, as the stage of labor intensive grafting is often the factor limiting the whole production process and preventing supply from meeting the large demands from the open-field production (10,000 to 100,000 plants per shipment). Specifically we will develop techniques to store grafted muskmelon seedlings for a short period of time (up to 4-6 weeks). Varied temperatures and light intensities will be tested using growth chamber based experiments. Effects of rootstocks will be also evaluated since some rootstocks (such as C. moschata) are known to add the chilling tolerance to the scions. 4) Development of an information website on grafted seedling technology and use. The main goal of the website is to allow stakeholders, extension personnel and researchers to access sufficient research and technical information to successfully introduce grafting to their operation, audience or research programs. The development of this website will lead to increased availability of such information.