Vegetable Grafting a Pest Management Perspective Sanjun Gu State Vegetable Specialist Lincoln University in Missouri
Outline Vegetable Grafting: some examples Vegetable Grafting: the Concept The Pest Management and Vegetable Grafting Grafting Methods: the very brief New challenges in Vegetable Grafting The labor concerns Vegetable Grafting Research
Lisbon, Portugal 2010 --Increase vigor and yield
Ji nan, China 2010 --The best watermelon
Increased vigor Enhanced cold tolerance Improved yield and quality Increased disease resistance
Photo: Dr. Wayne Fish --a Fusarium infected watermelon field
China, June 2010
Overwinter cucumber Cold resistance Disease resistance Much enhanced vigor High yield
Overwinter eggplants Cold resistance Disease resistance Much enhanced vigor High yield Enhanced color
In Japan and South Korea Watermelon: 91% Cucumber: 79% Eggplant: 57% Tomato: 41% Greenhouse production of the above: >90%
North/Central America About 40 millions of grafted hydroponic tomatoes (Ontario or British Columbia) Less than 100k grafted watermelons in open fields. Mexico had over 1250 acres of grafted tomatoes to overcome Fusarium. Mexico also has many grafted watermelons for Fusarium resistance (Abott&Cobb) Many farmers are interested in tomato grafting, especially with heirlooms because of the disease resistance
Scion Rootstock Graft Union What is Grafting?
Advantages: Pest management The phase out of Methyl Bromide Fumigation made the control of soil-borne disease difficult Resistance to some soil-borne diseases Fusarium wilt: melon, cucumber and tomato Bacterium wilt: tomato, eggplant. Verticillium wilt: tomato. Resistance to root-knot nematodes: cucumber, melon, watermelon, tomato, eggplant. Grafting can transfer resistance against the carmine spider mite from Lagenaria rootstocks to Cucurbita scions. Some rootstocks can render grafted plants resistant to some viruses.
Fusarium wilt: cucumber, melon, watermelon, tomato Bacterial wilt: tomato, eggplant Verticillium wilt: tomato, eggplant Phytophthora blight: pepper Nematode: tomato, melon
From Sally Miller, Ohio State Univ.
Tomato Spotted Wilt TSW incidence (%) Non-grafted: 79.8 a Self-grafted: 79.3 a Grafted: 59.5 b Rootstock: 1.3 c Zhao, 2010. Personal communication Riley et. al. 2011
Root Nematodes Ungrafted: 4.6 Self-Grafted: 4.4 Grafted: 0-0.8 Galls rated at a 0-5 scale. Zhao, 2010 personal communication
Disease Resistance of Grafted Vegetables Disease resistance /tolerance in grafted plants: not well understood. Tomato
(Rivard and Louws, 2008)
Tomato Rootstocks
Cucurbit Rootstocks
Rootstocks for Watermelon Grafting
Rootstocks for Cucumbers
Water and Nutrient Uptake Vigorous root systems of the rootstocks Increased uptake of water and minerals in grafted plants Lower ion concentration in xylem sap from grafted plants due to the increased absorption of water and possible dilution effect Rootstocks affect uptake and translocation of N, P, Mg, Fe, and Ca.
Vigor of Grafted Hybrid Modification of endogenous plant hormone (e.g., cytokinins) status by rootstocks Gene expressions in the scion associated with various aspects of plant metabolism can be affected by rootstocks (Zhang et al., 2008). long-distance translocation of RNA (Kudo and Harada, 2007) and protein (Gόmez et al., 2005) through phloem in grafted plants Rootstock-scion interaction
Grafting Flow Chart and Methods Select scions and rootstocks Plant seeds Schedule the best time for grafting Conduct grafting The healing process Acclimate the healed grafts Plant grafted transplants
Tubing Grafting method Some Pics. from NC State University website (The Peet group)
Insertion method
Cucumber: tongue approach method Rootstock: Cucurbita ficifolia Scion
Rootstock Scion
Cleft Method
From Xin Zhao
Management of Grafted (Tomato) plants Graft union should be at least 1 inch above the ground when planting Keep removing suckers or lateral shoots arising below the graft union Keep one or two leaders depending on the rootstock varieties used Other management the same as that for normal tomato plants
Suckers should be REMOVED
Cost Analysis WATERMELON Non-grafted (seedless) watermelon - $0.28 Grafted (seedless) Watermelon - $0.75 $704 more per acre (1,500 plants) 12.6% return on investment when Fusarium wilt is problematic Adapted from Dr. Wayne Fish
Tomato Plants Grafted and nongrafted transplant production costs were $0.59 and $0.13 in NC, and $1.25 and $0.51 in PA, respectively. Direct costs associated with grafting (e.g., grafting labor, clips, chamber, etc.) accounted for 37% to 38% of the added cost of grafting. Grafting labor was 11.1% to 14.4% of the cost of grafted transplant production. Seed costs represented 52% and 33% of the added cost of grafting at the two sites. Indirect costs (e.g., soil, trays, and heating) accounted for 10% and 30% of the added cost of grafting. Rivard et. al. 2010
Research Examples in the U.S. North Carolina State Univ.: tomato Ohio State Univ.: tomato, watermelon Univ. of Arizona: tomato and melon Clemson Univ.: watermelon Texas A&M: melon Univ. of Florida: watermelon and tomato USDA : watermelon and Solanaceous crops Some info from Dr. Zhao
Research at LU Grafting Compatibility with Heirloom Tomatoes Grafted watermelons Training and Nutrients management of Grafted Tomatoes Grafting greenhouse type cucumbers
Questions? Sanjun Gu State Horticulture Specialist Cooperative Extension and Research Program Lincoln University of Missouri 820 Chestnut Street Jefferson City, MO 65102-0029 Phone: 573-681-5524 Fax: 573-681-5313 E-mail: sanjun.gu@lincolnu.edu