Grafting can provide a site-specific management tool for some soilborne diseases. High Tunnels provide ~25 days early season extension over field- planted tomatoes. Total fruit productivity was higher in the High Tunnel system. Heirloom tomatoes grafted onto Beaufort and Maxifort rootstocks showed higher yields under our test conditions. Optimal planting date is March 20 th for Eastern NC. Summary and Conclusions Trust or German Johnson grafted onto Maxifort rootstock provided increased nutrient uptake, which may lead to a reduction of fertilizer inputs. Trust and German Johnson show increased plant growth when grafted onto Maxifort. The overall increased plant vigor in combination with increased nutrient uptake may lead to increased fruit yields. Results Grafting Heirloom Tomatoes for Disease Resistance and Nutrient Uptake Mary Peet, Suzanne O’Connell, Frank Louws, Cary Rivard, Chris Harlow North Carolina State University, Raleigh, NC (Top) Frank Louws, Chris Harlow, Cary Rivard, Steve Moore. (Bottom) Mary Peet, Suzanne O’Connell, Josh Moore Overview Grafting and High Tunnels are widely utilized for disease resistance and early season production in many parts of the world, but their benefits to growers of organic heirloom tomatoes in the Southeastern U.S. are not understood well. A Systems approach to the question compares aspects of production in two 30 ft x 98 ft tunnels with adjacent field plots. Factors considered include disease resistance, nutrient uptake, fruit quality, and timing of production. Additional supportive work includes controlled environment growth chamber (NCSU Phytotron) research and 17 on-farm grower trials coinciding with these studies. This research is being repeated for the 2008 season. Mean daily air temperatures in High Tunnels and Field plots. Bacterial Wilt Resistance. Plants grafted onto Asahi rootstock showed moderate resistance to bacterial wilt, while plants grafted onto DP 105 showed high resistance compared to non-grafted and self-grafted plants. Yield Differences Between Systems. Plants grown in High Tunnels yielded more fruit per plot over the entire growing season compared with plants grown in the field. Macro-Nutrient Content of the Leaf Tissue. Plants grafted onto Maxifort rootstock showed increased uptake of N, P, K, Ca & Mg compared to non-grafted plants. Self-graft plants showed increased uptake of N, P, K & Mg but not Ca, compared to non-grafted plants. a a b a b b a a b p=0.01p=0.001p<0.001 Main Treatment Effects on Yield. Significant differences were seen in total fruit yield over the entire growing season among Systems, Nutrient and Grafting treatments. SR-SARE R&E Grant Objectives Compare production dynamics of tunnel vs field production Environment Disease Productivity Economics Optimize cultural practices for high tunnels Nutrient inputs Planting date Investigate the role of grafting for field and tunnel production Beaufort Maxifort Rootstock / scion combinations Methods In the Phytotron, Maxifort-Trust, Trust-self, Maxifort-German Johnson, and German Johnson-self grafted plants, as well as non-grafted Trust and German Johnson were transplanted; Japanese tube-grafting protocol was used for grafts. Plants received standard Phytotron nutrient solution 1x/day pre-grafting and then 2x/day post-grafting. Destructive harvests were conducted one time per week for five weeks. Heirloom tomatoes were grown in High Tunnels and open fields at the Center for Environmental Farming Systems (CEFS) in Goldsboro, NC. Production systems were managed following NOP guidelines. Cherokee Purple was grafted onto two rootstocks, Maxifort or Beaufort, and tomatoes were transplanted into Tunnels on 3 separate dates. Three treatment levels of total nitrogen were applied to the each system at the following rates: 100lbs/A, 150lbs/A, and 200lbs/A. Fruit yield and quality were measured and evaluated.