Progress 09/01/11 to 08/31/16

Outputs
Target Audience:The goal of this SCRI coordinated project was to engage all sectors of the industry, translate outcomes to key stakeholders, communicate outcomes to peers, and train the next generation of research, extension and education personnel. A strategic component of engagement with our target audience was the development of a robust Advisory Board that provided feedback on the project and direction for future efforts. We specifically designed the Board to be multi-national, including representatives from large and small plant propagation companies, seed companies, robotic companies, and farmers who used (or wanted to use) grafted plants. The international partners brought a depth of experience to the project that was not available in the U.S. at the start of the project but over time "our renewal" Board added multiple U.S. partners who gained experience with or developed a high interest in grafting technologies, an indicator of how fast this industry is growing. We sought to enhance the CAPACITY to produce grafted plants and therefore core target audiences included international and national companies and individuals associated with vegetable seed companies, robotic companies that develop automated and semi-automated systems to graft plants, grafting nurseries, grafting supply and distribution companies and consulting experts. The USA now has major capacity to produce grafted plants in multiple regions and multiple sectors (box-stores, small-acreage farms, large acreage farms, conventional and organic grafted plants). Our project assisted entrepreneurs to launch grafting nurseries in AZ, CA, FL, NC, and PA as well as existing nurseries in CA, MI and Canada to begin grafting or expand the market to transplants used in open field markets. At the beginning of this project, the U.S. lacked substantive capacity to produce grafted vegetable plants. Currently, multiple existing and new companies have invested in grafting capacity and grafting technologies including automation. Companies are in diverse geographic regions, are certified organic or conventional, use traditional and novel technologies, and can graft a few thousand plants per year to 200K per week. We also sought to target audiences who could benefit from the use of grafted plants, so-called DEMAND for plants, and this included a broad range of stakeholders in many regions of the USA. Our primary target was commercial vegetable growers and the project engaged with large acreage conventional and organic growers of tomatoes, watermelons, muskmelon and eggplants. The project also engaged with small acreage conventional and organic growers from FL to OH to WA and CA. With the rapid emergence of high tunnel production systems the project also engaged with many high tunnel growers. The range of growers included first generation, limited resource growers and small-acreage growers to highly sophisticated operations and adoption on larger acreages. Through this process the SCRI team targeted most grower associations in the represented states and several national organizations e.g. National Watermelon Association. A core target audience included communicators who could effectively DISSEMINATE project outcomes. In addition to multiple state- or institutional-based articles over 50 popular articles or notes were written during the life of the project related to grafting including articles in the Tomato Magazine, American Vegetable Grower (Growing Produce family of publications), Vegetable Grower News and Southeast Farm Press. The majority of these outlets also featured or included web-based publications multiplying the outreach impact of this SCRI activity and other graft-related work that emerged in the USA. Other key target audiences included consumer horticulture stakeholders such as Master Gardeners (via multiple hands-on workshops), gardeners and consumers. Outreach programs targeted k-12 students and teachers - at various levels from elementary schools to technical community colleges. Our goal was also to translate outcomes to professionals, especially train-the-trainer professionals and peer extension and research personnel. These target audiences were reached through training programs and through local, regional, national and international conferences and publications - detailed elsewhere. Finally, we sought to target the next generation of researchers, extension professionals and educators. This was achieved by training undergraduates, grad students, postdoctoral professionals and visiting scholars also further detailed below. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Extension-based workshops and training is articulated below. Training students, postdocs and visiting scholars was a priority for this project. This fiscal year, the project engaged 28 undergraduates, 18 graduate students and 6 postdocs. K-12 programing was also conducted. For example USDA-ARS in FL trained several high school and undergraduate students (5) as well as interns (3) in the production of grafted tomato plants, using both manual and mechanically-assisted approaches. Two post-doctoral research associates were trained in the production of grafted plants and conducted both grower outreach as well as educational programs. In OHone doctoral student, one post-doctoral researcher, and two visiting scholars (all international) are fully engaged in our grafting-related research-outreach program and 4 undergrads and 3 additional graduate students were partially engaged. In NC, 4 graduate students were fully engaged in plant pathology, breeding, horticulture and weed science aspects of the project. Grafting graduate students presented a lecture in Vegetable Production (HS 431) on grafting for plant growth and disease management. This course consisted of 22 advanced undergraduate and graduate students in the College of Agriculture at NCSU. They also organized several hands-on workshops through the state, securing extension experience. NC also engaged multiple undergrads and biochemistry postdoc. In Az, five undergraduate students were trained through assisting with the small field trial of grafted watermelon as well as developing cucumber grafting techniques. One graduate student was trained through contribution to improvements of simulation of GRANDES system and working with a stakeholder (nursery) for optimizing their grafting operations [a web-based GRANDES interface is still under development. We are hoping to share the beta website soon.]; a visiting scholar participated in the project for improving cucurbit grafting method, and for overcoming issue of tomato rootstocks susceptible to intumescence. At U-FL, both graduate and undergraduate students were involved in the project by carrying out or assisting various research and outreach activities. A postdoctoral associate also worked on the project. Vegetable grafting labs have been integrated into two courses taught on campus in the field of horticultural crop production and organic and sustainable production. A visiting PhD student sponsored by the China Scholarship Council was trained on melon grafting and conducted a study on grafted specialty melons during his one-year visit. Likewise KS trained 4 undergrads in horticulture, 3 grad students in urban food systems and a postdoc; WA trained 3 grad students in horticulture and Clemson 2 grad students during this reporting period. How have the results been disseminated to communities of interest?Outreach was a strategic component of this SCRI and was conducted with high success and through two major mechanisms. First, we continued to evaluate economic and social metrics to guide the direction of emerging grafting technology advancements and this process engaged stakeholders (Obj3). We developed enterprise budgets to evaluate economic viability under various changing factors and customizable tools. These products are disseminated as decision tools for growers. Previous work has demonstrated that grafting can be economically attractive due to advantages in disease control and horticultural benefits. We also continued to focus on optimizing grafting operations by working directly with existing or new companies. For example, using the GRANDES decision support system, we closely worked with a grafting nursery in Arizona (i.e., Grafted Growers) and helped them to improve the efficiency of the existing small grafting operation as well as to design a new larger grafting facility (to be built in 2017) by optimizing labor input. In collaborating with Drs. Kubota and Son, this company acquired USDA SBIR grants (Phase I, $100K and Phase II, $600K) to continue working in this optimization of grafting labor input using the expertise and GRANDES we developed in this project (an example of becoming self-supporting beyond the project funding). The AZ team also evaluated the economics of rotation period for grafted versus non-grafted watermelon plants. The tradeoff between planting a high value crop like watermelons more frequently versus rotating with a less profitable crop is key to determining the value of a grafted watermelon transplant. A static linear programming model to solve for optimal crop mixes, utilizing different levels of crop rotation constraints on the frequency of planting watermelons, showed that when utilizing the same yield for grafted vs non-grafted transplants, a rotation constraint that is greater than 1 in 4 years yields a grafted transplant value of $1.40/plant. Therefore if grafted watermelon transplants are less than this price and land is scarce enough that the producer needs to plant watermelons more frequently than 1 in 4 years on their farm to meet the demand of their markets, grafting confers an additional advantage. At UFL, economics analysis of grafted cherry tomatoes under high tunnel production at an organic farm was conducted. Results showed that grafting led to significantly higher partial net returns, mainly because of increased yield from grafted plants and the high price that the farmer could receive by directly selling the locally-grown organic tomatoes to consumers in the early season. A customized decision support tool for tomato grafting was developed with default values built in based on on-station experiments of grafted tomato production. This tool allows growers to input values and a sensitivity analysis that assumes different scenarios in output price and grafted transplant cost can also be conducted to enable decisions. Second, we conducted extensive outreach and training programs for stakeholders, designed a helpful website and developed traditional and novel translational outputs/products to facilitate greater and more effective application of grafting as a business and grafted plants as vegetable production tools. In this reporting period, the team published 10 peer reviewed publications; 13 research abstracts; 3 proceedings; 19 print or digital extension products; gave 54 research or extension vegetable grafting-related presentations in multiple states and countries and conducted 21 hands-on workshops/classes. The GTWG team expects to publish an Online Vegetable Grafting Manual, now near completion, that details extension recommendations for grafting and caring for plants given a diversity of crops and regional considerations. Over 1900 stakeholders were directly served in dissemination forums e.g. 300 participants received hands-on training on grafting techniques in addition to general information about grafting during the last Great Plains Growers Conference Vegetable Grafting Clinic and an immersion room was designed where growers gained experience and knowledge related to grafting. In FL, grafting workshops and presentations were conducted at grower conferences and training sessions. Information on grafted plants and their use was presented to grower communities at the Gadsden Tomato Forum and the Tri-State melon meeting. Industry partners were updated at the Tri-Est annual sales meeting. USDA-ARS conducted hands-on grafting workshops with the target audiences of tomato producers, Master Gardeners, home gardeners, and students. In NC, graduate student-led grafted vegetable workshops were delivered to a mixture of stakeholders from home gardeners, extension agents, small and large-scale growers, and educators. Workshops covered grafted vegetable mechanics, production practices, evidence-based decision making paradigms, economic viability, and management potential for soil-borne diseases and environmental stresses. Likewise, OH created many opportunities for development and training in the area of vegetable grafting. The programs (including hands-on workshops) engaged growers, farm employees, extension-research professionals, IPM program scouts and consultants, educators, undergraduate students, and master gardeners. Collectively, people reached directly through these programs (>130) represent the Great Lakes and Northeast U.S. regions and three other countries (Honduras, Ecuador, Guatemala). Complementary efforts occurred in other states. A key dissemination mechanism for the SCRI, and method to secure feedback from stakeholders, has been through national symposiums. In December of 2015 we organized the 4th National Vegetable Grafting Symposium that included representatives from each sector of our stakeholder industry and multiple talks and discussions of project outcomes and industry activities. We also linked this symposium to dissemination activities through the 1st National Extension In-service Training on Vegetable Grafting. The nineteen participants in the daylong training represented twelve universities (paid for by this grant) and a non-profit organization; collectively, they represented all regions of the U.S. Participants were provided with focused overviews of the status and potential future of vegetable grafting, a resource toolkit, training in grafting-based research and outreach, and abundant opportunities for discussion with experts, including for the purpose of setting future research and extension objectives. Multiple similar train-the-trainer programs were conducted at state and local offerings. The Symposium training concluded with participants visiting the Vegetable Grafting Clinic setup as part of the trade show at the annual Great Lakes Fruit, Vegetable, and Farm Market Expo in Grand Rapids, MI. Open for 2.5 days, the Clinic contained posters, publications, videos, and other educational items. The Clinic was also staffed round-the-clock by grafting experts who answered questions and provided training in grafting upon request. Approximately 200 people visited the Clinic and the average residence time was estimated as 30 min, although many visitors remained longer. Many of the project outputs and outcomes were also delivered through our vegetable grafting website http://www.vegetablegrafting.org with 18,516 page views by IP addresses representing all U.S. states, more than 160 countries and commercial, academic, organizational, and government sectors this reporting period. Finally, as part of Grafting Technologies Working Group, AZ organized international field trips to Italy, Japan, and Taiwan. These field trips gave valuable opportunities to see the various technologies used in grafting nurseries and to learn from their nursery experiences. Several US Business personnel attended these tours to translate knowledge to USA opportunities. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? This project optimized grafting technologies to reduce costs of producing and distributing grafted seedlings, and provided capacity and leadership to make technologies readily available to U.S. open-field producers (Obj1). The engineering team of the Grafting Technologies Working Group (GTWG) developed a grafting nursery decision support system (AZ; GRANDES) to optimize efficiency of grafting operations in U.S. vegetable nurseries. This system includes 100 variables that calculate capital, fixed, and variable costs to optimize grafting operations. GRANDES simulation was compared with human expert decisions to optimize the labor management and used successfully to assist a new grafting nursery in AZ to design efficient grafting operations. Significant contributions regionally and nationally were made to enhance grafting capacity and efficiency. The outcomes include: 1) improving grafting and healing methods for tomato and watermelon seedlings, in which the notable contribution is development of the region/climate/crop specific protocols for growing scion and rootstock (RS) as well as designing healing systems (FL, KS, OH, SC, WA). For example, we found that applying anti-transpirant products to watermelon seedlings prior to grafting improved grafting success in grower friendly operations; 2) a better understanding of the physiology of grafted plants post grafting, including photosynthesis, transpiration, RS axillary bud development, and hormonal balance between scion and RS (AZ, FL, KS, OH, SC, WA). For example, a simple method for propagating grafted tomato (leaf removal) was developed that increased grafting success rates by 5-15% and allows for reduced management immediately post-grafting, helpful to inexperienced grafters. Likewise, a series of experiments determined that temperature alone did not affect healing variables but grafting efficiency improved under higher light intensity with LED as the solo light source. In pepper grafting work, survival and regrowth were greater in plants secured with tubes and the use of adhesives needs further work; 3) A patented method to kill the apical meristem of watermelon RS was refined and increases the grafting window by several days for optimum RS readiness, eliminates regrowth of RS shoots and enhances grafting success; 4) The pathology/IPM team contributed to a better understanding of pathogen transmission and potential disinfestation methods to reduce the transmission of pathogens. For example, a quick soak in 10% Clorox or 70% EtOH completely eliminated transmission of the gummy stem blight fungus in watermelon. Additional impact was made through various stakeholder driven problem solving projects. For example, AZ developed lighting strategies to solve the issue of a physiological disorder (intumescences) widely observed in interspecific tomato RS grown under UV-deficit humid environments of high-tunnels, greenhouses and growth rooms. This project also integrated discovery-based, applied and on-farm research (OFR) to optimize field production outcomes (Obj2). Bacterial wilt (BW) of tomato is a major soil-borne disease of the Southeastern USA. Current management practices do not offer satisfactory control. Multi-location on-farm and greenhouse evaluations of diverse public and private germplasm resources spanning open-pollinated and hybrid types have identified 4 RS from 4 different companies and 3 RS from public institutions that provide 80-100% plant stand under diseased conditions that cause 30-100% susceptible plant losses. These RS have been recommended and adopted by growers using a few thousand plants up to 60 acres with a variety of scions for BW management. Additional germplasm from diverse origins have been identified for future RS development to enhance resistance durability. Research to elucidate resistance mechanisms in these RS is ongoing and molecular markers for BW resistance are pursued for combining multiple resistance loci that confer high levels of resistance into regionally adapted RS breeding material. A mapping population of about 170 BC-derived lines has been developed from a cross and field-level resistance was tested for QTL discovery. Verticillium also remains a challenge in temperate climates. In WA, multiple tomato RS, breeding lines, and cultivars were evaluated in greenhouse and field experiments for use in tomato and eggplant production systems. Specific RS, and interestingly, RS*scion combinations suppressed colonization when grafted to tomato or eggplant scions. In some cases yield benefits were observed (eggplant on selected tomato RS or an eggplant RS 'Java'; but not in tomato systems). In NC parallel work 2 RS conferred a tomato yield benefit. Eggplant RS conferred a yield advantage in tomato systems in FL and requires further work. A series of experiments hypothesized specific RS may modulate TYLCV severity in scions in FL but under high disease pressure disease pressure was not reduced but yield increased. RS consistently offered an advantage in multiple regional experiments to manage root-knot nematode (RKN) in open field systems and high tunnels, where pressure tends to get high. A major challenge is RKN in cucurbit crops and working with USDA-Charleston, this project discovered/advanced RS that confers superior RKN control, combined with Fusarium resistance. Multiple OFR and research station trials discovered parameters to optimize nutrient and irrigation inputs and growing systems for grafted vegetables. Preliminary work suggests no-till tomato decreases yield but grafted plants can compensate for a portion of this decrease and points to the need for further optimization of NT systems. Assays to conduct RS screening for drought, salinity, and temperature tolerance and development of a functional assay to assess RS vigor were optimized. For example, 14 RS inclusive of commercially and wild accessions were evaluated and vigor scales developed to enable growers to make decisions based on needed vigor effects (low to high). A multi-year field study determined the critical period for weed control (CPWC) in grafted watermelon exposed to a mixed weed populations. Graft treatments included two interspecific hybrid RS 'Carnivor' and 'Kazako'; these RS conferred lower yield than the control and the CPWC varied among all graft treatments, suggesting weed management timing must be adjusted for grafted watermelon. Multiple experiments also assessed RS effects on fruit quality. Tomato fruit from 3 yr of replicated high tunnel trials in KS were evaluated for organoleptic quality as well as antioxidant capacity. Vigorous RS such as 'Maxifort' and 'Colosus' can increase fruit yield by as much 40% without reducing fruit taste or nutritional quality. In FL, tomato fruit were collected to develop a model to correlate nondestructive near infrared (NIR) absorbance measurements with soluble solids content and titratable acidity. For tomato, grafting effects on fruit quality varied depending on the RS used, overall, few negative impacts of grafting on fruit quality were observed with some benefits e.g. increased lycopene content. A NC field study tested the effects of grafting on fruit quality in both standard and mini-melons (cultivars 'Exclamation' and 'Exstazy', respectively) to a selection of twenty-one commercially available RS and analysis is ongoing. No resistance to chill injury was found among watermelon from 8 RS and a 'Melody' scion compared to non-grafted fruit. Identification of phenolic compounds from grafted and non-grafted watermelon flesh showed that caffeic and coumaric acid were highly glycosolated with several sugars, and indicates that further quantification will be challenging. A simple and relatively inexpensive firmness tester for watermelon fruit was designed and tested as an alternative to hand held penetrometers and reduced worker fatigue and improved rapidity and result reproducibility.

Publications

• Type: Journal Articles Status: Published Year Published: 2015 Citation: Guan, W., X. Zhao and D.J. Huber. 2015. Grafting with an interspecific hybrid squash rootstock accelerated fruit development and impaired fruit quality of galia melon. HortScience 50:1833-1836
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Guan, W., and X. Zhao. 2015. Effects of grafting methods and root excision on growth characteristics of grafted muskmelon plants. HortTechnology 25:706-713
• Type: Journal Articles Status: Accepted Year Published: 2016 Citation: Djidonou, D., A.H. Simonne, K.E. Koch, J.K. Brecht and X. Zha.o 2016. Nutritional quality of field-grown tomato fruit as affected by grafting with interspecific hybrid rootstocks. HortScience. In press
• Type: Journal Articles Status: Accepted Year Published: 2016 Citation: Eguchi, T., R. Hernandez, and C. Kubota. 2016. Far-red and blue light synergistically mitigate intumescence injury of tomato plants grown under UV-deficit light environment. HortScience 51:712-719
• Type: Journal Articles Status: Accepted Year Published: 2016 Citation: Hu, B., M.A. Bennett and M.D. Kleinhenz. 2016. A new method to estimate vegetable seedling vigor, piloted with tomato, for use in grafting and other contexts. HortTechnology: in press
• Type: Journal Articles Status: Accepted Year Published: 2016 Citation: Spalholz, H., and C. Kubota. 2017. Rootstock affected in- and post-storage performance of grafted watermelon seedlings at low temperature. HortTechnology: In press
• Type: Journal Articles Status: Accepted Year Published: 2017 Citation: Kubota, C., C. Meng, Y.J. Son, M. Lewis, H. Spalholz, and R. Tronstad 2017 Horticultural, systems-engineering and economic evaluations of short-term plant storage techniques as a labor management tool for vegetable grafting nurseries. PLOS One accepted pending revision
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Schultheis, J.R., W.B. Thompson, and R. Hassell. 2015. Specialty melon yield and quality response to grafting in trials conducted in the southeastern United States. Ist International Symposium on Vegetable Grafting, Wuhan, China, Eds: Bie, Z. et al. Acta Horticulturae 1086. pp. 269-278.
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Suchoff, D.H., C.G. Gunter, J.R. Schultheis and F.J. Louws. 2015. On-farm grafted tomato trial to manage bacterial wilt. Ist International Symposium on Vegetable Grafting, Wuhan, China, Eds: Bie, Z. et al. Acta Horticulturae 1086. pp. 119-127-278.
• Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Eguchi, T., R. Hernandez, and C. Kubota. 2016. End-of-day far-red lighting combined with blue-rich light environment to mitigate intumescence injury of two interspecific tomato rootstocks. Acta Horticulturae 1134:163-170
• Type: Other Status: Published Year Published: 2016 Citation: Miles, C., L. Hesnault, S. Johnson, P. Krelder and S. Dabirian. 2016. Vegetable grafting: watermelon. Washington State University, Extension. FS100E (updated) http://cru.cahe.wsu.edu/CEPublications/FS100E/FS100E.pdf
• Type: Other Status: Published Year Published: 2016 Citation: Hassell, R. March 25 2016. US: New grafting robot reduces labor costs Fresh Plaza T http://www.freshplaza.com/article/155510/US-New-grafting-robot-reduces-labor-costs?utm_campaign=newsletter&utm_medium=ed1&utm_source=s1
• Type: Other Status: Published Year Published: 2016 Citation: Rivard, C. October 18 2016. How shoot removal, rootstock cultivar affect grafting tomatoes Vegetable Growers News http://vegetablegrowersnews.com/news/shoot-removal-rootstock-cultivar-affect-grafting-tomatoes/
• Type: Other Status: Published Year Published: 2016 Citation: Louws, F. January 25 2016. Project sharpens interest in benefits of vegetable grafting Vegetable Growers News http://vegetablegrowersnews.com/news/project-sharpens-interest-in-benefits-of-vegetable-grafting/
• Type: Other Status: Published Year Published: 2015 Citation: Kubota, C. C. Miles and X. Zhao. December 15 2015. Field trip to vegetable grafting nurseries in Italy slated for March Growing Produce http://www.growingproduce.com/vegetables/field-trip-to-vegetable-grafting-nurseries-in-italy-slated-for-march/
• Type: Websites Status: Published Year Published: 2016 Citation: USDA-SCRI website: vegetablegrafting.org
• Type: Journal Articles Status: Accepted Year Published: 2016 Citation: Meyer, L.J., M.M. Kennelly, E.D. Pliakoni, and C.L. Rivard. 2016. Leaf removal reduces scion adventitious root formation and plant growth of grafted tomato. Scientia Horticulturae (in press).
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Masterson, S.A., M.M. Kennelly, R.R. Janke, and C.L. Rivard. 2016. Scion shoot removal and rootstock cultivar affect vigor and early yield of grafted tomatoes grown in high tunnels in the Central United States. HortTechnology 26:399-408.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Masterson, S.A., M.M. Kennelly, R.R. Janke, and C.L. Rivard. 2016. Microclimate and scion leaf removal to improve the success of grafted tomato seedlings. HortTechnology 26:261-269.

Progress 09/01/14 to 08/31/15

Outputs
Target Audience:This is a compressive project that engages a wide diversity of key stakeholders. Identified target and engaged audiences include: Primary growers - Vegetable nurseries; Greenhouse growers; Cucurbit Growers in the United States; Tomato Growers in the United States; Organic, sustainable, and conventional vegetable producers; Small farm producers; State and National Watermelon Association Members; State and National Tomato and Vegetable Grower Association Members; Core industries - Vegetable Seed companies; Horticultural automation technology suppliers; Computer scientists; Industrial engineers; Consumer Audiences - Gardeners/hobbyists; Master gardeners; High school teachers; K-12; vegetable consumers; Academic and Scientific Stakeholders- University Research and Teaching Faculty and Extension personnel; Graduate and undergraduate students; National and International Research Scientists. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Training of students, professionals and growers is a major impact of the program. Program activities for training included hands-on workshops and formal training sessions that engaged growers, farm employees, extension-research professionals, IPM program scouts and consultants, educators, undergraduate students, and master gardeners. Many of the extension related training outcomes are articulated below. Lectures or labs at 3 Universities featured grafting of vegetables and project outcomes in undergrad and graduate student courses. Graduate and undergraduate students were emphasized in training programs at all sites. Graduate and undergraduate students were emphasized in training programs at all sites. Over 8 undergraduate and 12 graduate students were trained during this reporting year including international students from Libya, Iran and other countries. For example, a Ph.D. student completed his work in Systems and Industrial Engineering and another was trained through the GRANDES work. Three graduate students finished their masters in horticulture (breeding, physiology, weed science) or plant pathology and 2 of them continued on for a PhD; the third got a superior job as a cucurbit breeding technician. A weed science student completed her PhD and secured a superior job in industry. Three FL students enrolled in the community college have had work-study in applications of biotechnology while working on ToMV resistance genes. Two international visiting scholars were trained in grafting technologies at two Universities. Training sessions that attracted attendees from Honduras, Ecuador and Guatemala were conducted. How have the results been disseminated to communities of interest?Objective 3. Evaluate economic and social metrics to guide the direction of emerging grafting technology advancements. Economic output was designed to enable stakeholders to make decisions as an effective outreach tool. Multiple research experiments, on-farm-work and models were complimented with in-depth analysis of economic metrics. Economic metrics guided the development of the GRANDES model and impacted design of efficient and profitable propagation methods. Field research was complimented by a series of studies and papers using partial budgeting to determine the economic impact of grafting technologies. Economic work developed tools and matrices for multiple production systems (high tunnel, organic, conventional field e.g. tomato steak and weave systems) to enable grower decisions concerning the potential utility of grafting or not on their operations. Objective 4. Translate outcomes and facilitate the application of grafted plants as a significant tool in vegetable crop production. Consistent with the proposed outreach plan, results have been disseminated in multiple forms and using multiple platforms, including: a) lectures and presentations during scientific/technical and grower/industry programs, b) hands-on workshops hosted by universities and industry partners, c) trade and scientific/technical publications (printed and online versions), d) the project-related website (www.vegetablegrafting.org), and e) public listservs and private and group email and phone interactions. A minimum of 1500 primary and secondary stakeholders representing all U.S. states were reached directly through lectures/presentations, workshops, publications, and email and phone interactions. Also, the project website (www.vegetablegrafting.org) we helped develop in 2014 and manage has had nearly 56,000 page views by IP addresses representing all U.S. states, 156 countries and commercial, academic, organizational, and government sectors. This website functions as a comprehensive and interactive online portal for sharing research-based vegetable grafting information and resources. A core component of this project is the two-way and stakeholder driven work that is conducted with businesses and through on-farm research and demonstrations. This design links the practice and science of grafting across all industry sectors. Research outcomes are rapidly translated into the industry and industry issues and needs are likewise effectively communicated to guide research activity. For example, in this past year, multiple seed companies linked with PIs to evaluate potential rootstocks for the US market, robotics companies partnered with PIs to optimize grafting efficiencies, nurseries have engaged teams of experts in start-up or expanded work, and many experiments have been done through grower driven and engaged on-farm-research in conventional, organic and high-tunnel field production systems. This participatory model has enhanced project directions and outcomes that serve the industry well. Twenty eight stakeholder workshops or training sessions were conducted representing each state with PIs reaching an estimate 685 stakeholders, primarily fruiting vegetable farmers. Many of these workshops included hands-on training to do grafting. In one series of sessions, watermelon was utilized as a means of educating consumers on health benefits of fruits and vegetables. A recipe for watermelon shrimp salad was combined with a short paragraph on the benefits of watermelon. The salad was prepared by a chef with the Dole Nutrition Research Institute, with a 30 person audience; recipes and product were distributed. Additional information on watermelon was distributed to various local health organizations and alliances for consumer use. This outreach effort was complimented by 48 extension presentations offered at local, regional and national Extension conferences on multiple aspects of grafting technologies including current data, uses and opportunities with grafted plants. The impact of outcomes was enhanced through partnerships with major media outlets. For example, 10 media articles featured grafting in local to national publications including the American Vegetable Grower Magazine and Growing Produce. A comprehensive day-long technical symposia with a follow-up stakeholder Advisory Board meeting was held in January 2015 in cooperation with the SE Fruit and Vegetable Conference in Savannah GA. Over 125 people participated representing the diversity of the industry and from multiple countries. This 3rd National Vegetable Grafting Symposium seemed to take a turn from previous ones: people did not come just to learn or out of curiosity but appeared to be more vested to enable the grafting industry to grow. The symposium1) summarized the current status and expected future of grafting as a technology for enhancing U.S. vegetable production systems - profit, resource efficiency and sustainability; 2) increased understanding of challenges and opportunities associated with preparing and using grafted vegetable plants; 3) strengthened and diversified of partnerships required to widen the application of vegetable grafting as cornerstone technology; and 4) described USDA-SCRI team goals and approaches. The Advisory team strongly directed and endorsed the work the USDA-SCRI program was doing. This outreach effort was complimented with the public release of 13 digital media presentations posted at our Vegetablegrafting.org site among others, primarily representing output from the 3rd National Vegetable Grafting Symposium. The extension outreach program was complemented by communication of results to the scientific community. As part of our training, 6 research abstracts, primarily presented by students at professional scientific meetings, were published. This was complemented by 7 published proceedings, including presentations at the first International ISHS Grafting Conference (Wuhan, China) and 31 research presentations at professional scientific meetings including invited talks in Wuhan, China, South Africa and multiple regions of the USA. Research based information was compiled into 2 technical publications highlighted project outcomes. Finally, in this past reporting period, 18peer-reviewed journal articles were published. What do you plan to do during the next reporting period to accomplish the goals?This project ends August 31, 2016. Major emphasis will be to complete current projects, continue to publish outputs and disseminate outcomes. Several field projects will continue after the end date and be funded by other funds, especially to bring thesis projects to closure. We will organize another (4rth) National Vegetable Grafting Symposium and full-day national agent training program. This USDA-SCRI is on schedule and has met or exceeded proposed objectives as originally outlined. Stakeholders and University personnel have identified the priority to seek opportunities to continue the momentum of this SCRI effort.

Impacts
What was accomplished under these goals? Objective 1. Optimize grafting technologies to reduce costs of producing and distributing grafted seedlings, and make technologies readily available to U.S. open-field producers. The development of a grafting nursery decision support system (AZ; GRANDES) to establish efficient grafting operations was nearly completed. This system includes 100 variables that calculates capital, fixed, and variable costs to optimize grafting operations. During the reporting year, outcomes included two different types of interfaces (designed for a wide range of users to answer typical questions such as production costs and the other was for a more robust customized service for enterprise use with our consultation) and computation speed was enhanced. The GRANDES team visited three enterprises in AZ, CA and Canada and discussed possible collaborative projects. Technologies and methods have been advanced to enable more grafted growers to optimize their systems. The propagation working group also developed a patented (SC) propagation method that reduces overall cost by eliminating watermelon rootstock (RS) regrowth, reduced the need for large cell sizes and extended the grafting period from a few days to a few weeks. The amount of grafted transplants in a greenhouse setting can now be the same as a regular transplant operation. Tomato grafting was optimized in OH using dye movement and plant growth parameters as indicators of healing success. Although light and temperature interactions were often significant, higher LED light intensity (range 5 to 300 μmol/m2/s) improved graft healing and plant regrowth whereas T had less dramatic impact. Light also was more impactful than RH. It was concluded NAA and BA as tested in this study using a range of concentrations are unlikely to significantly alter graft healing in tomato. Additional experiments were conducted to determine the impact of cultivar, pruning, adhesive glue and other variables on the efficiency and success of grafting. Applying anti-transpirant products to watermelon plants prior to grafting improved grafting success from 75% (control) up to 93% and healing chamber conditions were optimized for WA conditions. Our project also assisted entrepreneurs to launch grafting nurseries in AZ, CA, NC, and PA as well as existing nurseries in CA, MI and Canada to begin grafting or expand the market to transplants used in open field market. Objective 2. Integrate discovery-based, applied and on-farm research to optimize Cucurbit and Solanaceous field production and produce quality outcomes. The Cucurbit working group conducted extensive work with muskmelon and triploid watermelon where there is limited to no resistance to Fusarium wilt (FW) and root knot nematode (RKN). In FL, RKN susceptible rootstocks were combined with available and new nematicides to integrate management strategies for optimum yield and pest management; in the long-term, superior resistance in rootstocks is preferred. In portions of our work (SC trial) reduced grafted watermelon plant populations offered similar or higher yield than standard systems, reducing transplant costs. In some of the NC and FL trials, grafting did not offer a yield advantage in the absence of biotic or abiotic stress and weed population thresholds were optimized in grafted and non-grafted watermelon. Grafted watermelon plants were evaluated in a field trial for their cold tolerance in the early spring crop in Arizona. The yield of grafted watermelon plants yielded nearly 100% more than non-grafted plants. The group also focused on yields and harvest quality with the postharvest WG. Fruit on grafted plants held up in the field providing growers with a longer harvest (2wks) window. The grafted fruit had more lycopene and was much firmer and contained less water and portends well for expanded fresh cut operations. Precision and accuracy of fruit firmness was advanced through the development of a novel firmness test. Cold sensitive studies revealed grafted fruit appears to express more injury on the rind than non-grafted fruit. Comparison of 21 rootstocks with 2 scions provided a data set for further recommendations for growers and showed that firmness was lower in fruit from nongrafted plants while 14 rootstocks yielded more firm watermelons in both scions. Lycopene, soluble solids content, pH and citrulline content are being analyzed. This database anticipates future work to optimize yield and enhance fruit quality. A value added product of watermelon jerky was developed to take advantage of the extra firmness of grafted watermelon. The Solanaceous working group evaluated grafted tomatoes for planting density, fruit yield and quality, nutrient and water use efficiency, and for the management of soil-borne pests such as bacterial wilt (BW), Verticillium wilt (VW), RKN and FW. A series of experiments were conducted in high tunnel, organic and conventional systems in OH and KS to optimize rootstock selection and understand the impact of varying inputs and management practices e.g. grafted plants with vigorous rootstocks enhanced yield in organic tunnel systems under lower fertility regimes. Parallel experiments verified the utility of rootstock to manage RKN in field systems where growers need to grow RKN sensitive heirloom and other tomato selections and in FL (ARS) rootstocks were evaluated against 4 RKN species including Meloidogyne arenaria, M. floridensis, M. incognita, and M. javanica. Complimentary open field experiments were also conducted in FL. Four farm field trials (2 certified organic; 2 sustainable) were conducted (ARS) to assess grafted heirloom tomato varieties and FW and RKN management. UFL also used (indeterminate and determinate) tomato varieties and observed excess rootstock growth was encountered and impacted yield negatively. A series of RS were evaluated in plant spacing trials and a pilot study was conducted in the greenhouse to assess growth of grafted tomato plants in response to water stress. Replicated field trials also demonstrated the use of systemic acquired resistance activating compounds improves BW resistance in grafted tomato. Three NC field experiments demonstrated 'Cheonggang' (Monsanto), RST-106 (D Palmer Seed) and Shield (RijkZwaan) resulted in near 100% plant stand compared to <20% with non-grafted "Red-Mountain" (round tomato P=0.05) and about 80% plant stand with 'Picus" (Roma-type; P=NS) and increased marketable yield (P=0.05 for both scions) 27% to over 300% in the presence of BW pressure. In the absence of BW pressure at 2 other sites, these rootstocks significantly increased yield or generated yields comparable to non-grafted controls depending on the scion or site. RS did not appear to affect fruit set efficiency but this work requires additional study. The goal to diversify available QTLs for BW resistance was advanced through observations of a BC2F2 segregating population of 232 individuals with a broad range of BW responses. In WA, 12 RS, breeding lines and cultivars were screened VW (race 2) tolerance (underway) and in NC high VW-race2 disease pressure demonstrated RS did not impact incidence or severity but two RS, including one bred in the US, appeared to significantly enhance yield (data analysis underway). In a WA, one eggplant and tomato RS increased eggplant yield in VW hot fields. Data on tomato RS and weed management effects was finalized in NC with critical thresholds defined for optimum tomato performance. It was determined that the use of scions and rootstocks with similar alleles for virus (ToMV) resistance is extremely important to increase grafted plant survival in the presence of this virus. All commercially available rootstocks have been characterized for the ToMV-resistance alleles in cooperation with grafted plant propagators and this knowledge base is critical for sectors of the industry (e.g. heirloom growers). Activity related to training, economics and outreach are reported in sections below.

Publications

• Type: Journal Articles Status: Published Year Published: 2014 Citation: Keinath, A. P., and Hassell, R. L. 2014a. Control of Fusarium Wilt of Watermelon by Grafting onto Bottlegourd or Interspecific Hybrid Squash Despite Colonization of Rootstocks by Fusarium. Plant Disease 98:255-266
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Keinath, A. P., and Hassell, R. L. 2014b. Suppression of Fusarium Wilt Caused by Fusarium oxysporum f. sp niveum Race 2 on Grafted Triploid Watermelon. Plant Disease 98:1326-1332.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Kunwar, S., Paret, M. L., Jones, J. B., Ritchie, L., Freeman, J. H., and Olson, S. M. 2014. Management of bacterial wilt of tomato with a combination of grafting and a systemic acquired resistance inducer. Phytopathology 104:64-64.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Kunwar, S., Paret, M. L., Olson, S. M., Ritchie, L., Rich, J. R., Freeman, J., and McAvoy, T. 2015. Grafting Using Rootstocks with Resistance to Ralstonia solanacearum Against Meloidogyne incognita in Tomato Production. Plant Disease 99:119-124.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Mahmud, I., Kousik, C., Hassell, R., Chowdhury, K., and Boroujerdi, A. F. 2015. NMR Spectroscopy Identifies Metabolites Trans located from Powdery Mildew Resistant Rootstocks to Susceptible Watermelon Scions. Journal of Agricultural and Food Chemistry 63:8083-8091.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Rysin, O., and Louws, F. J. 2015. Decision Tool for Growers to Evaluate Economic Impact of Grafting Technology Adoption: An Application to Open-field Conventional Tomato Production. Horttechnology 25:132-138.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Daley, S. L., and Hassell, R. L. 2014. Fatty Alcohol Application to Control Meristematic Regrowth in Bottle Gourd and Interspecific Hybrid Squash Rootstocks Used for Grafting Watermelon. Hortscience 49:260-264.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Daley, S. L., Adelberg, J., and Hassell, R. L. 2014a. Improvement of Grafted Watermelon Transplant Survival as a Result of Size and Starch Increases Over Time Caused by Rootstock Fatty Alcohol Treatment: Part I. Horttechnology 24:343-349.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Daley, S. L., Wechter, W. P., and Hassell, R. L. 2014b. Improvement of Grafted Watermelon Transplant Survival as a Result of Size and Starch Increases Over Time Caused by Rootstock Fatty Alcohol Treatment: Part II. Horttechnology 24:350-354.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Djidonou, D., Lopiano, K., Zhao, X., Simonne, E. H., Erickson, J. E., and Koch, K. E. 2015. Estimating nitrogen nutritional crop requirements of grafted tomatoes under field conditions. Scientia Horticulturae 182:18-26.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Eguchi, T., and Kubota, C. 2015. Cotyledonary Axillary Shoot Control by Fatty Alcohol Application for Grafting Tomato. Horttechnology 25:569-574.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Guan, W. J., Zhao, X., Dickson, D. W., Mendes, M. L., and Thies, J. 2014. Root-knot Nematode Resistance, Yield, and Fruit Quality of Specialty Melons Grafted onto Cucumis metulifer. Hortscience 49:1046-1051.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Thies, J. A., Buckner, S., Hassell, R., and Levi, A. 2014. Development and use of root-knot nematode resistant rootstocks for managing Meloidogyne incognita in grafted watermelon. Phytopathology 104:117-118.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Thies, J. A., Levi, A., Ariss, J. J., and Hassell, R. L. 2015a. RKVL-318, a Root-knot Nematode-resistant Watermelon Line as Rootstock for Grafted Watermelon. Hortscience 50:141-142.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Thies, J. A., Ariss, J. J., Hassell, R. L., Buckner, S., and Levi, A. 2015b. Accessions of Citrullus lanatus var. citroides Are Valuable Rootstocks for Grafted Watermelon in Fields Infested with Root-knot Nematodes. Hortscience 50:4-8.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Thies, J. A., Buckner, S., Horry, M., Hassell, R., and Levi, A. 2015c. Influence of Citrullus lanatus var. citroides Rootstocks and Their F1 Hybrids on Yield and Response to Root-knot Nematode, Meloidogyne incognita, in Grafted Watermelon. Hortscience 50:9-12.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Nilsen, ET; Freeman, J; Grene, R; Tokuhisa, J. 2104. A Rootstock Provides Water Conservation for a Grafted Commercial Tomato (Solanum lycopersicum L.) Line in Response to Mild-Drought Conditions: A Focus on Vegetative Growth and Photosynthetic Parameters. PLos One 9:e115380
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Chaudhari, S. K.M. Jennings, D.W. Monks, D.L. Jordan, C.C. Gunter and F.J. Louws. 2015. Response of Grafted Tomato (Solanum lycopersicum) to Herbicides. Weed Technology 29:800-809.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Chaudhari, S. K.M. Jennings, D.W. Monks, D.L. Jordan, C.C. Gunter, N.T. Basinger and F.J. Louws. 2015. Response of eggplant (Solanum melongena) grafted onto tomato (Solanum lycopersicum) rootstock to herbicides. Weed Technology doi: 10.1614/WT-D-15-00079.1
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Hassell, R. and Daley, S. 2015. Fatty alcohol rootstock treatment: an overview of a new approach to cucurbit grafting. Acta Hort. (ISHS) 1086:71-77
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Miles, C., Wimer, J. and Inglis, D. 2015. Grafting eggplant and tomato for Verticillium wilt resistance. Acta Hort. (ISHS) 1086:113-118
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Rysin, O., Rivard, C. and Louws, F.J. 2015. Is vegetable grafting economically viable in the United States: evidence from four different tomato production systems. Acta Hort. (ISHS) 1086:79-86
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Suchoff, D., Gunter , C., Schultheis, J. and Louws, F.J. 2015. On-farm grafted tomato trial to manage bacterial wilt. Acta Hort. (ISHS) 1086:119-127
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Schultheis, J., Thompson, W. and Hassell, R. 2015. Specialty melon yield and quality response to grafting in trials conducted in the southeastern united states. Acta Hort. (ISHS) 1086:269-278
• Type: Websites Status: Published Year Published: 2015 Citation: vegetablegrafting.org

Progress 09/01/13 to 08/31/14

Outputs
Target Audience: This is a compressive project that engages a wide diversity of key stakeholders. Identified target and engaged audiences include: Primary growers - Vegetable nurseries; Greenhouse growers; Cucurbit Growers in the United States; Tomato Growers in the United States; Organic, sustainable, and conventional vegetable producers; Small farm producers; State and National Watermelon Association Members; State and National Tomato and Vegetable Grower Association Members; Core industries - Vegetable Seed companies; Horticultural automation technology suppliers; Computer scientists; Industrial engineers; Consumer Audiences - Gardeners/hobbyists; Master gardeners; High school teachers; K-12; vegetable consumers; Academic and Scientific Stakeholders- University Research and Teaching Faculty and Extension personnel; Graduate and undergraduate students; National and International Research Scientists. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? To date, this project had a significant educational component under which graduate and undergraduate students were trained. Eighteen graduate students were fully or partially funded and trained through this project and two undergraduate senior thesis projects were completed. Three lectures or labs featured grafting of vegetables and project outcomes in undergrad and graduate student courses; Grower training workshops reached 146 people at multiple sites in NC, FL and OH. Over 12 presentations were given at Grower conferences to train growers and agents with an estimated attendance of 9 to 70 people per session. Additional details are provided below in the Extension accomplishments. How have the results been disseminated to communities of interest? Objective 4. Translate outcomes and facilitate the application of grafted plants as a significant tool in vegetable crop production. The team established a vigorous and reliable communication infrastructure employing several formats. Extension and outreach goals were accomplished through web-based, digital and print media, and conferences, workshops, and field day events. Private- and public-sector stakeholders participated reciprocally as learners and instructors, while events engaged local and international audiences affiliated with the conventional and organic production of Solanaceous and Cucurbit crops in fields and high tunnels at multiple scales. We developed and launched (in March 2013) a vegetable grafting website (http://www.vegetablegrafting.org). To our knowledge, the website is the first comprehensive and interactive online portal for sharing research-based vegetable grafting information and resources. The website houses print and other resources, including program recordings, directories of experts, links to other websites and resources, and program announcements. With nearly 28,000 page views, users are from all U.S. states, 128 countries, and commercial, academic, organizational, and government IP addresses. A listserv (http://hcs.osu.edu/vpslab/vegetable-grafting-list) was initiated in May 2014 to help identify industry priorities and design and implement outreach plans. The listerv has 84 subscribers (excluding project team members) representing commercial, academic, organizational, and government affiliations, and provides a searchable archive of topic threads and has increased the reach of project-based communication and learning. Forty-seven stakeholder-oriented publications with local to international reach have been produced, such as a Tomato Grafting Guide (http://hcs.osu.edu/vpslab/grafting-guide) that was downloaded 800 times by stakeholders representing 48 U.S. states, 52 countries and six continents. Educational content has been distributed through popular press (SouthEast Farm Press, American Vegetable Grower Magazine, Vegetable Growers News). More than 42 vegetable grafting-related presentations (27 hours) at 37 venues in 11 states and 33 hands-on workshops, demonstrations and trainings in nine states have been delivered. Comprehensive day-long technical symposia with follow-up stakeholder Advisory Board meetings were held in November 2012 and 2013 in Maitland, FL and San Diego, CA, respectively. These symposia were developed by project personnel, the first of their kind in the U.S. Specific goals for symposia were: 1) summarize the current status and expected future of grafting as a technology for enhancing U.S. vegetable production systems – profit, resource efficiency and sustainability; 2) increase understanding of challenges and opportunities associated with preparing and using grafted vegetable plants; 3) strengthen and diversify of partnerships required to widen the application of vegetable grafting as cornerstone technology; and 4) describe USDA-SCRI team goals and approaches. A total of 175 participants represented 54 companies, three organizations, 11 universities, and eight countries. More than 50% of attendees had an industry or other non-academic affiliation; there was equal interest in Cucurbit and Solanaceous crops, and participant feedback (through a formal survey) indicated they benefitted from presentations and look forward to follow-up program(s). Recordings of the technical presentations on grafted plant preparation, use and performance, and economy have been downloaded or viewed from our website http://www.vegetablegrafting.org/resources/grafting-symposia/ nearly 900 times. The symposia drew in and educated our Advisory Board about project activities and enabled productive discussions and feedback the following day. This project had a significant educational component under which graduate and undergraduate students were trained. Eighteen graduate students were fully or partially funded and trained through this project and two undergraduate senior thesis projects were completed. What do you plan to do during the next reporting period to accomplish the goals? Activities: multiple field and lab experiments will be coordinated at the local, state, regional and national levels; surveys of adoption and of workshop/training programs will be conducted; senior scientists, post-docs, graduate students and undergraduate students will be trained; stakeholders will be engaged in all activities including private companies, growers, consumers, extension personnel and scientists. Events: Two annual national conferences are planned as well as a series of demonstration sites, field days, workshops, University level classes, and trainings. Products anticipated include audio and video products; data and databases; decision software; novel technology, methods, or techniques; train-the-trainer manuals or related products; a website; scientific and extension products advancing information, skills, and technology for individuals, companies, growers and other key stakeholders; students graduated in agricultural sciences.

Impacts
What was accomplished under these goals? Objective 1. Optimize grafting technologies to reduce costs of producing and distributing grafted seedlings, and make technologies readily available to U.S. open-field producers. The grafting technology working group established three sub-objectives: 1a) Develop dynamic simulation models for a decision-support system for propagators to plan, design, and optimize grafting propagation operations and supply chains; 1b) Research and evaluate new propagation and distribution methods; and 1c) Develop good agricultural practices for vegetable grafting. Obj. 1a. A team from the University of Arizona (AZ) has developed a framework for economic and logistical analysis of planned and current propagation systems. This framework includes over 100 variables as well as associated mathematical equations to facilitate planning and design of grafted seedling propagation facilities and operations. The framework allows for the determination of capital, fixed, and variable costs related to grafting operations. This information has also been used to develop a dynamic simulation model including all steps in a commercial grafting operation. This affords potential entrepreneurs the ability to evaluate various scenarios of propagation workflow, supply chain, and logistical analyses and associated costs. Analysis utilizing the framework and simulation model indicated that short term cold storage of grafted seedlings was economically and logistically feasible and that variable costs could be reduced to 8.9 cents per plant in fully automated operations. This research led to revised R&D by a grafting automation stakeholder that minimized operational costs and improved suitability for the North American market. Obj. 1b. Research-based recommendations for low temperature storage conditions and for potential use with un-rooted grafted cuttings were developed for the most widely grafted species to allow shipping and grow-out form distal places. The use of low temperature storage of grafted seedlings could increase grafting capacity without increasing labor input. The application of a fatty alcohol to the meristem of cucurbit rootstock seedlings successfully destroyed this region, resulting in a longer propagation window and improved graft success. These outcomes have attracted the attention and support of multi-national seed producers and should decrease input costs for grafted seedlings and the potential for inclusion of grafted fruiting vegetables into U.S. open-field production. Obj. 1c. Research to determine the effectiveness of disinfectant products for cleaning tools used in the grafting process and of materials used to manage powdery mildew and gummy stem blight in cucurbit seedling productions was conducted. Seven disinfectants were tested but none prevented the transmission of gummy stem blight during cucurbit grafting indicating more work is needed. In separate studies a “hypersensitive necrosis” was observed whereby plants wilted and died within one week. This was associated with rootstocks with high ToMV virus resistance grafted to scions with no known resistance. This confirmed reports of this phenomenon from Japan and is of concern to U.S. producers who graft ToMV susceptible heirlooms. Our project also assisted entrepreneurs to launch grafting nurseries in AZ, CA, NC, and PA as well as existing nurseries in CA, MI and Canada to begin grafting or expand the market to transplants used in open field market. Objective 2. Integrate discovery-based, applied and on-farm research to optimize field production and produce quality outcomes. Activities, outcomes, and impact within this objective were divided into two working groups,2 a) Cucurbits, and 2b) Solanaceous crops. Obj 2a. The Cucurbit working group has been focusing on muskmelon and triploid watermelon where there is limited to no resistance to Fusarium wilt (FW) and root knot nematode (RKN). Experiments identified several rootstocks that reduced FW incidence for grafted watermelon and muskmelon, however plants were highly susceptible to RKN. RKN is generally present in sandy soils where FW is also present, so resistance to both pests is needed. In separate studies, accessions from Cucumis metuliferus reduced the root galling caused by RKN. This work has resulted in increased interest by growers, seed corporations, and propagators. This interest has translated into a new grafting venture in North Carolina that will primarily serve watermelon and muskmelon growers. Grafted plants cost more than traditional transplants, and it was found that watermelon planting density could be reduced by 25% without affecting yields but cantaloupe could not. Fruit from grafted watermelons could be held in the field a week longer than non-grafted watermelons and still provided firmer fruit for fresh cut preparation extending the harvest window for growers. However, grafting had some negative impacts on sensory attributes and fruit quality (improved lycopene content and firmness, but decreased citrulline content); there were no clear trends for cantaloupe and specialty melons. Obj 2b. The Solanaceous working group conducted over twenty research station and on-farm experiments in six states to evaluate grafted tomatoes for planting density, fruit yield and quality, nutrient and water use efficiency, and for the management of soil-borne pests such as bacterial wilt (BW), Verticillium wilt (VW), RKN, FW, and fusarium crown and root rot (FCRR). Results indicated severity of BW, VW, and RKN were significantly reduced with correct rootstock selections. Root galling was reduced by 97% and bacterial wilt mortality was reduced by 92% when certain rootstocks were employed. Although there was increased early season vigor, flowering, fruit set and yield for heirloom tomato grafted onto Tomato leaf curl virus (TYLCV)-resistant rootstocks, there was no significant difference in virus incidence when compared with non-grafted plants. There has been no clear indication that grafting leads to increased fruit yield in the absence of disease, as some results indicate improvement while others do not. In multiple experiments there were no significant differences in fruit quality, and sensory analysis showed mixed results for fruit appearance, acceptability, and flavor. Grafted tomato had improved water and nitrogen use efficiency on sandy soils. The positive results have increased interest among commercial growers and propagators. A cooperating propagator in California has been producing grafted plants since 2011 primarily for the hobby and home-owner market, but in 2014 sales to commercial producers accounted for 15% of their nearly 1 million grafted plants produced; they also now produce 60,000 grafted watermelons for commercial agriculture. Growers of all scales are using grafted tomato across the U.S., from several hundred plants in protected culture to over 30 acres in open-field production on one farm. Objective 3. Evaluate economic and social metrics to guide the direction of emerging grafting technology advancements. The economic working group conducted extensive work that supported sub-objectives 1 and 2 of objective 1. Economic analyses supported Obj. 1a and 1b to develop the propagation framework and simulation models. Primary research emphasis was on the evaluation of costs and benefits of grafted vegetables for the propagator and end user. With regard to objective 2, an outcome was the development of budgets for various tomato production systems (conventional field, organic field, conventional high tunnel and organic high tunnel) using grafted plants. Economic analysis indicated that using grafted transplants generally resulted in positive net returns but some production systems were more sensitive to transplant cost due to their narrow profit margin. Therefore, a decision support matrix that includes results from these analyses is underway.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Suchoff, D., Louws, F., Gunter, C., Schultheis, J.R 2013. On-farm Grafted Tomato Trial to Manage Bacterial Wilt. Proceedings of the Annual International Research Conference on Methyl Bromide Alternatives.
• Type: Conference Papers and Presentations Status: Awaiting Publication Year Published: 2014 Citation: Meng, C., Y.J. Son, C. Kubota 2014 The Effect of Early Order Commitment in Order-Driven Supply Chain. Proceedings of the 2014 Industrial and Systems Engineering Research Conference
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Rosskopf, E.N., C. Kubota, S. Adkins, N. Kokalis-Burelle, and J.C. Hong. 2013. Importance of Rootstock and Scion Compatibility for Grafting Heirloom Tomatoes. Proceedings of the Annual International Research Conference on Methyl Bromide Alternatives
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Daley, J. July 2013 Palm Desert CA USA Annual Conference of the American Society for Horticultural Science Mapping Alternaria cucumerina resistance in Cucumis melo.
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Daley, S. February 2013 Orlando FL USA Southern Region American Society for Horticultural Science 73rd Annual Meeting A new grafting procedure decreases grafting cost and increases grafting efficiency by elimination rootstock re-growth.
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Daley, S. February 2013 Orlando FL USA Southern Region American Society for Horticultural Science 73rd Annual Meeting Use of fatty alcohol treatments to control rootstock regrowth in grafted watermelon (Cirullus lanatus [Thunb.].
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Daley, S. July 2013 Palm Desert CA USA Annual Conference of the American Society for Horticultural Science The effect of rootstock age on grafting ability, re-rooting, and field performance of grafted watermelon transplants.
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Daley, S. July 2013 Palm Desert CA USA Annual Conference of the American Society for Horticultural Science Rootstock age affects graft ability and rootstock re-rooting of grafted watermelon transplants.
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Daley, S. November 2013 San Diego CA USA 2nd Vegetable Grafting Symposium Rootstock age, after fatty alcohol treatments, affects yield and fruit quality of grafted seedless watermelon.
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Hassell, R. November 2013 San Diego CA USA 2nd Vegetable Grafting Symposium Rootstock age affects graft ability and rootstock re-rooting of grafted watermelon transplants.
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Hassell, R. November 2013 San Diego CA USA 2nd Vegetable Grafting Symposium Within-row spacing affects yield in grafted seedless watermelon.
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Keinath, A. November 2013 San Diego SC USA 2nd Vegetable Grafting Symposium Evaluation of grafting to control Race 2 of Fusarium wilt on watermelon.
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Nguyen, N. July 2013 Palm Desert CA USA Annual Conference of the American Society for Horticultural Science Assessing root characteristics of cucurbit rootstocks using a simple germination test.
• Type: Conference Papers and Presentations Status: Other Year Published: 2014 Citation: Miller, G Feb 2014 Dallas TX USA Watermelon Research & Development Working Group - SRASHS Grafted watermelon root length density and distribution under different soil moisture treatments
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Perkins-Veazie, P. July 2013 Palm Desert CA USA Annual Meeting of the ASHS Graftin rootstock, scion, and field holding affects on seedless watermelon fruit quality.
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Silverman, E. November 2013 San Diego CA USA 2nd Vegetable Grafting Symposium Evaluating bacterial wilt resistance of tomato rootstocks in North Carolina.
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Suchoff, D. November 2013 San Diego CA USA 2nd Vegetable Grafting Symposium 2013 On-farm grafted tomato trial to manage bacterial wilt.
• Type: Conference Papers and Presentations Status: Other Year Published: 2014 Citation: Kleinhenz, M.D. July 2014 Orlando FL USA Annual Meeting of the ASHS Toward more effective selection of tomato rootstock and scion varieties for use in U.S. soil-baswed production, including organic
• Type: Conference Papers and Presentations Status: Other Year Published: 2014 Citation: Kleinhenz, M.D. July 2014 Orlando FL USA Annual Meeting of the ASHS A new protocol may help reveal pre- and post-grafting environment effects on early-phase healing in grafted tomato seedlings
• Type: Conference Papers and Presentations Status: Other Year Published: 2014 Citation: Kleinhenz, M.D. April 2014 Wooster, OH USA 2014 OFFER Spring Symposium Resources to enhance organic vegetable yield and quality
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Kleinhenz, M.D. November 2013 San Diego CA USA 2nd Vegetable Grafting Symposium Grafting and rootstock effects on fruit yield and composition of organic, field-grown tomato.
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Kleinhenz, M.D. July 2013 Desert Palm CA USA Annual Meeting of the ASHS Fruit yield and composition as functions of grafting and irrigation regimen in an organic high tunnel system,
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Kleinhenz, M.D. July 2013 Desert Palm CA USA Annual Meeting of the ASHS Grafting and rootstock efffects on tomato yield and quality in an organic, midwestern, multi-harvest system.
• Type: Conference Papers and Presentations Status: Other Year Published: 2014 Citation: Kubota, C. March 2014 Wuhan China 1st ISHS International Symposium on Vegetable Grafting Horticultural, systems-engineering and economic evaluations of low temperature storage of grafted seedlings as tool for grafting labor management
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Kubota, C. November 2013 Orlando FL USA Vegetable Grafting Symposium Emerging technologies for grafting propagation.
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Kubota, C. November 2013 San Diego CA USA 2nd Vegetable Grafting Symposium Short-term storage of grafted vegetable seedlings.
• Type: Conference Papers and Presentations Status: Other Year Published: 2014 Citation: Guan, W. and X. Zhao 2014 Wuhan China 1st ISHS International Symposium on Vegetable Grafting Physiological changes in grafted melon plants with a hybrid squash rootstock
• Type: Conference Papers and Presentations Status: Other Year Published: 2014 Citation: Zhao, X. and D. Djidonou 2014 Wuhan China 1st ISHS International Symposium on Vegetable Grafting Nitrogen uptake and root distribution of grafted tomato under different levels of nitrogen fertilization
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Zhao, X. February 2013 Orlando FL USA Southern Region American Society for Horticultural Science 73rd Annual Meeting Sensory attributes of tomato and muskmelon fruits as affected by grafting.
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Ozores-Hampton, M. Nov 2013 Maitlind FL USA Annual Research Conference on Methyl Bromide Alternatives and emissions Reductions (MBAO) On experiences in South Florida with grafting and challenges and opportunities of the green-mature tomato industry
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Ozores-Hampton, M. November 2013 San Diego CA USA 2nd Vegetable Grafting Symposium Grafting roma-type of tomato in Florida.
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Zhao, X. February 2013 Orlando FL USA Annual Conference of the Southern Region American Society for Horticultural Science Sensory attributes of tomato and muskmelon fruits as affected by grafting.
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Zhao, X. November 2013 San Diego CA USA 2nd Vegetable Grafting Symposium The influence of grafting on fruit quality: A research update on grafted tomato and melon.
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Zhao, X. November 2013 San Diego CA USA 2nd Vegetable Grafting Symposium Economic analysis of grafted tomato production.
• Type: Conference Papers and Presentations Status: Other Year Published: 2014 Citation: Kokalis, N., F.B. Iriarte, D.M. Butler, J.C. Hong, and E.N. Rosskopf May 2014 Cape Town South Africa 6th International Congress on Nematology Nematode management in Florida vegetable and ornamental production
• Type: Conference Papers and Presentations Status: Other Year Published: 2014 Citation: Rosskopf, E. July 2014 Orlando FL USA Annual Meeting of the ASHS Effects of different Tomato mosaic virus resistance in grafted tomato scions and rootstocks
• Type: Conference Papers and Presentations Status: Other Year Published: 2014 Citation: Rosskopf, E. April 2014 Live Oak FL USA University of Florida Grafting Workshop Rootstock and Scion Disease Resistance for Grafting 'Heirloom' Tomatoes
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Rosskopf, E. November 2013 San Diego CA USA 2nd Vegetable Grafting Symposium Importance of rootstock and scion tomato mosaic virus resistance for grafting heirloom tomatoes.
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Rosskopf, E. August 2013 Kissimmee FL USA Florida Small Farms and Alternative Enterprises Conference Practical aspects of producing and using grafted tomato plants
• Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Freeman, J. February 2013 Orlando FL USA Southern Region American Society for Horticultural Science 73rd Annual Meeting Effect of plant population and pruning on grafted tomatoes for open field production
• Type: Other Status: Published Year Published: 2014 Citation: DuBose, V. Keinath, A. 3/29/2014 On-farm evaluation of two tomato rootstocks with resistance to bacterial wilt Plant Disease Management Reports 8 V222 https://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2014/V222.pdf
• Type: Other Status: Published Year Published: 2013 Citation: Keinath, A. Hassell, R. 2013 On-farm evaluation of grafted seedless watermelon for control of Fusarium wilt race 2. Plant Disease Management Reports 7 V033 http://www.plantmanagementnetwork.org/pub/trial/pdmr/volume7/abstracts/v033.asp
• Type: Other Status: Published Year Published: 2014 Citation: Snipes, Z. Keinath, A., DuBose, V. 3/29/2014 Field Evaluation of Two Rootstocks to Manage Fusarium Wilt in Watermelon Plant Disease Management Reports 8 V237 http://www.plantmanagementnetwork.org/pub/trial/pdmr/reports/2014/V237.pdf
• Type: Journal Articles Status: Awaiting Publication Year Published: 2013 Citation: Daley, S. R. Hassell 2013 Fatty alcohol treatments result in an increase in seedling size and carbohydrate content in potential grafted watermelon rootstocks. HortTechnology In review
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Keinath, A. R. Hassell Feb. 2014 Control of Fusarium wilt of watermelon by grafting onto bottlegourd or interspecific hybrid squash despite colonization of rootstocks by Fusarium Plant Disease 98 255-266 http://apsjournals.apsnet.org/doi/pdfplus/10.1094/PDIS-01-13-0100-RE
• Type: Journal Articles Status: Awaiting Publication Year Published: 2014 Citation: Keinath, A. R. Hassell in press Suppression of Fusarium wilt caused by Fusarium oxysporum f. sp. niveum race 2 on grafted triploid watermelon Plant Disease 98 http://apsjournals.apsnet.org/doi/pdfplus/10.1094/PDIS-01-14-0005-RE
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Keinath, A. 2013 Susceptibility of cucurbit rootstocks to Didymella bryoniae and control of gummy stem blight on grafted watermelon seedlings with fungicides. Plant Disease 97 1018-1024 http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-12-12-1133-RE
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Ling, K.-S. A. Levi, S. Adkins, C.S. Kousik,G. Miller, R. Hassell, and A. Keinath 2013 Development and field evaluation of multiple virus-resistant bottle gourd (Lagenaria siceraria). Plant Disease 97 1057-1062 http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-07-12-0639-RE
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Miller, G. C. Wells, A. Khalilian, H. Farahani and R. Hasell Jan-14 Field evaluation and performance of capacitance probes for automated drip irrigation of watermelons. Agricultural Water Management 131 124-134
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Miller, G. C. Wells, A. Khalilian, H. Farahani and R. Hasell Aug-13 Grafted watermelon root length density and distribution under different soil moisture. HortScience 48 1021-1026 http://hortsci.ashspublications.org/content/48/8/1021.full.pdf
• Type: Journal Articles Status: Awaiting Publication Year Published: 2014 Citation: Lewis, M. Kubota, C., Tronstad, R., Son, Y.J. 2014 Scenario-Based Cost Analysis for Vegetable Grafting Nurseries of Different Technologies and Sizes HortScience In press
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Djidonou, D. Z. Gao, and X. Zhao Oct-13 Economic analysis of grafted tomato production in sandy soils in Northern Florida. HortTechnology 23 613-621 http://horttech.ashspublications.org/content/23/5/613.abstract
• Type: Theses/Dissertations Status: Other Year Published: 2013 Citation: Snipes, Z. B. M.S. Thesis Dec. 2013 Managing Fusarium Wilt in Watermelon Production

Progress 09/01/12 to 08/31/13

Outputs
Target Audience: This is a compressive project that engages a wide diversity of key stakeholders. Identified target and engaged audiences include: Primary growers - Vegetable nurseries; Greenhouse growers; Cucurbit Growers in the United States; Tomato Growers in the United States; Organic, sustainable, and conventional vegetable producers; Small farm producers; South Carolina Watermelon Association Members; North Carolina Watermelon Association Members; North Carolina Tomato and Vegetable Grower Association Members; Core industries - Vegetable Seed companies; Horticultural automation technology suppliers; Computer scientists; Industrial engineers; Consumer Audiences - Gardeners/hobbyists; Master gardeners; High school teachers; K-12; vegetable consumers; Academic and Scientific Stakeholders- University Research and Teaching Faculty and Extension personnel; Graduate and undergraduate students; National and International Research Scientists. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Data is compiled by institution rather than working group. At the University of Arizona, one MS student was trained and completed his thesis entitled, ‘Development of Short Term Storage Techniques for Grafted Vegetable Seedlings’. One Ph.D. student who took an integral part of the interdisciplinary project including industrial engineering, computer science, horticulture science, and economics. One undergraduate student conducted two experiments on grafting storage and healing and presented her outcomes in the annual conference of American Society for Horticultural Science. At Clemson University: Three graduate students are being trained and will graduate in Dec. 2013 and May 2014. Because of the training, one graduate student was hired as an Extension agent to focus on vegetable and fruit production and pest management. Two hands-on grafting workshops have been used to educate local growers on grafting benefits and methods. (April and Dec 2013). A Watermelon Field Day at EREC (July11) was conducted. Research plots were used to train Clemson University graduate and undergraduate students and Extension agents in watermelon disease diagnosis. At the University of Florida, Workshops were organized to provide training on tomato grafting (Ozores-Hampton). A vegetable grafting talk (Zhao) was incorporated into an in-service training on new technology for commercial vegetable production. A vegetable grafting exhibit (Zhao) was organized at the Florida Small Farms Alternative Enterprises Conference and was very well received. Grafted vegetable production was also introduced to undergraduate students in horticultural crop production and organic and sustainable crop production courses at the University of Florida (Zhao). An invited seminar on vegetable grafting was given to undergraduate interns in the Disney Epcot Agricultural Sciences Internship Program (Zhao). Three graduate students participated in the grafted tomato research. At Virginia Tech, 99 individuals were taught multiple grafting techniques on watermelon and tomato. Grafted tomato plants were adopted by two producers that have been trained through this project. At the USDA ARS Florida, two technicians and one PI have become proficient in the use of the Helper Robotech Co. grafting robot for grafted plant production for commercial and experimental trials. The USDA, ARS team conducted a “hands-on” grafting training activity at the Florida Small Farms Conference. A Plant Pathology book lab procedure was developed for the use of nematode-resistant tomato rootstocks. At Ohio State University: one M.S. program was completed, one PhD program was initiated, and two visiting scholar experiences were completed, four undergraduate students earned extensive experience in the preparation, care and use of grafted plants; through lecture and hands-on sessions, 60 undergraduate students and three faculty and staff received training in grafting fundamentals. At NCSU: Four graduate students (3 fully- or partially-funded on this project and another) were trained in various aspects of grafting vegetable production. The most unique aspect of this project was the way in which graduate students self-organized and worked in small groups to accomplish tasks together. Graduate students in this area were highly motivated to work collaboratively and put that desire into action. Several undergrad students were trained through field and lab-based projects. For example, the tomato and watermelon tests were used as ways to train undergraduate students in laboratory technique, observation, critical skills, and data analysis. Both students and staff learned differences and changes (weight loss, decay, changes in carotenoids) that can happen as tomatoes and watermelons ripen and senesce. One undergrad in the last year who coordinated field projects went on for a graduate degree in agroecology. Four grower-based grafting workshops and a science café were led by the students. Grafting presentations were offered at most local and regional vegetable conferences including the SE Fruit and Vegetable Expo, NC Tomato Growers Annual Meeting, NC Greenhouse Growers annual meeting and a Western NC field day. Grafting was incorporated into an undergrad course (28 students). How have the results been disseminated to communities of interest? Data is compiled by institution rather than working group. The University of Arizona team developed simulation models (with detailed 2D/3D animation capabilities) and preliminary economic analysis based on them have been shared with governmental, industrial, and academic communities interested in grafting technology in conferences including Vegetable Grafting Symposium held in November, 2012. Outcomes of research for new propagation and distribution methods were also presented at the annual conference of American Society for Horticultural Science in July 2013. Reflecting the increasing interest from the public (gardeners and school teachers), a vegetable grafting workshop was organized in Phoenix metropolitan area with approximately 30 participants. As an outcome of the workshop, a community college in Phoenix started including vegetable grafting in a course that is part of their urban horticulture program. Another grafting workshop was co-organized with our stakeholder members at the 2013 OFA Short Course in Ohio in July 2013. Through the University of Arizona Vegetable Grafting Information website, investigators communicated with various industry and academic communities worldwide (4-5 email questions per month). Investigators also travelled to meet or host the visitation of industry (propagators and farmers) who are interested in examining and introducing the technology. The Propagation WG (AZ leadership) organized two online meetings for the Propagation Technology WG to exchange information. Visitations were made to a grafting robotics industry in the Netherlands, the largest grafting nursery using indoor production facilities in Japan, a new grafting nursery in Mexico, a nursery for bedding plant and garden vegetable transplants in California, and traditional open-field nurseries in Florida and California. An outcome is that the robotic industry started R&D toward a grafting robot suitable for US applications. At Clemson University: Thirteen presentations have been given at three scientific meetings: Southern Region ASHS (Feb. 2013), American Society of Horticultural Scientists (July 2013), and Vegetable Grafting Symposium (Nov 2013); Publication in Review: Daley S., R. Hassell, 2013. Fatty Alcohol treatments result in an increase in seedling size and carbohydrate content in potential grafted watermelon rootstocks. HortScience (in review). A vegetable grafting workshop was held to train small, minority, beginning, and limited-resources farmers. Other presentations: Veg Expo Myrtle Beach - November 26-28, SCWA annual meeting - January 11-13, , Delaware presentation on Watermelon Research in SC - January 14-16, Georgia Watermelon Growers Association Meeting - January 25-27, Watermelon Field Day at EREC - July 11. At the University of Florida, research results have been disseminated through presentations at the American Society for Horticultural Science (ASHS) Conference (Ozores-Hampton and Zhao), Southern Region ASHS Conference (Zhao), Florida Small Farms Alternative Enterprises Conference (Ozores-Hampton and Zhao), and Florida Seed Association Convention (Ozores-Hampton). At Virginia Tech, six presentations were presented to clientele groups and other scientists. USDA ARS Florida staff conducted presentations at workshops and scientific meetings, publications in scientific literature. At Ohio State University, programs (integrated lecture and hands-on activities); presentations; field tours; numerous types of publications; digital and online resources; phone, email and on-site consultation; on-farm research and demonstration plots. OSU delivered 4 technical and 7 extension presentations; delivered 4 workshops featuring lecture and hands-on activities; published a 78-page grafting guide distributed to more than 40 U.S. states and 38 countries; developed and posted (online) a seed-to-grafted plant calculator; prepared and posted three grafting methods videos in English, Spanish and Chinese languages with more than 60,000 views in 2013. At NCSU: Four grower-based grafting workshops and a science café (and featured in the Winston Salem Journal) were led by the students. Grafting presentations were offered at most local and regional vegetable conferences including the SE Fruit and Vegetable Expo, NC Tomato Growers Annual Meeting, NC Greenhouse Growers annual meeting and a Western NC field day. NCSU participated in a grafting symposium at the annual American Phytopathology Society (APS) meeting. Two talks were presented at an industry conference and published in Proceedings of the Int. Res. Conf. on Methyl Bromide Alternatives and Emissions Reduction or posted at the national Vegetable Grafting Symposium website (graftvegetables.org). Three presentations and abstracts were published through APS reaching a scientific audience. Likewise, an international audience was presented with team outputs at the IPM2: 10th conference of the European Foundation of Plant Pathology; October 4, 2012. Production budgets developed for field conventional, multi-bay tunnel conventional, field organic and high tunnel organic tomato production systems were published on-line and included in publications. Through the life of the project, the teams engaged more than 53 third party partners that contributed resources, time and expertise. The team also organized the first Annual Grafting Symposium in the USA in Orlando FL with over 100 attendees with a productive level of dialogue among leaders in the grafting and fruiting vegetable industry. Several prominent business ventures emerged from the conference and SCRI generated information was translated to primary stakeholders. The industry advisory team provided feedback and direction for priority efforts. What do you plan to do during the next reporting period to accomplish the goals? Data is compiled by institution rather than working group. At the University of Arizona, during the final project year, we plan to continue scenario based, comprehensive economic analyses as well as supply chain analyses and optimization using the developed simulation models in a highly flexible manner for various situations/conditions (e.g. locations, seasons, products, and costs/rates). We will also continue to refine the guidelines for the use of low temperature storage and un-rooted grafted cuttings. Finally we will integrate the dynamic computer simulation approach into the systems-based evaluation of these new technologies that we have developed during the past years. Our work will have more emphasis on publications out of our outcomes and acquiring future funding to support our continuous effort to adopt vegetable grafting technology in the US. At Clemson University: Oral presentation and poster at International vegetable grafting symposium in China (March 2014); Continuing grafting education workshops with hands-on training; Continuing research to explore grafted transplant in-row spacing and new grafting method; A manuscript on grafting watermelon to manage Fusarium wilt race 2 will be submitted for publication. At the University of Florida: In August 2013, roma-type tomato was planted to evaluate the effects of grafting planting depth in yield and fruit quality production in South Florida. A second season of roma-type and grape tomato trial is in the transplant-house with a planting date in November 2014. The study on yield response of grafted tomato plants to different planting densities will be repeated in fall 2013 and spring 2014. We also plan to evaluate the postharvest shelf life of tomato fruit from grafted plants. At Virginia Tech, one more field season is necessary to determine the most appropriate cultural practices for grafted tomatoes in open field production. At the USDA ARS Florida, complete evaluation of field and greenhouse trials which are currently underway, compile and analyze data, prepare reports and manuscripts for publication. Participate in the University of Florida Grafting Workshop to be held next spring. At Ohio State University, research studies outlined earlier will be continued and related follow-up studies will be initiated. The vigorous, multifaceted approach used to date to transfer research-based information to commercial application will be continued. The extension working group will continune to enahnce the website and the second symposium outcomes posted. At NCSU: Additional on-farm and research experiments will be conducted to complement work completed to date. SNPs analysis to map potential QTLs for BW resistance will continue. A new type of fresh cut watermelon product for fast food sales will be explored since grafting increases flesh firmness. Students and teams will focus on analyzing data and writing peer reviewed and extension publications. We will also pursue delivery of this information to the scientific community and grower communities in the coming months through a series of annual association meetings planned in the coming season.

Impacts
What was accomplished under these goals? The project is organized around 4 core objectives and a series of sub-objectives. The Objectives are managed by working groups (WG) that are multi-institutional and inter-disciplinary engaging multiple 3rd party stakeholders. Objective 1: To optimize grafting technologies to reduce costs of producing and distributing grafted seedlings and make the technology readily available to US open-field producers. The AZ team refined the previously identified variables and parameters related to a grafted seedling propagation facility design (capital costs) and operation (variable costs). The dynamic simulation model for grafting nursery operations was completed and used for evaluating various technologies (such as introducing grafting automation) and different production scenarios. AZ also provided leadership and completed a series of experiments examining the chilling sensitivity and storability of grafted vegetable seedlings under low temperature (5, 10 and 12oC). As a new distribution method of grafted plants, they further investigated the possible use of un-rooted grafted cuttings and explored long distance shipping methods. Clemson developed a new cucurbit grafting method using fatty alcohol treatment of rootstocks to eliminate the rootstock meristem enhancing graft success and reducing rootstock suckers. UFL investigated the application of abscisic acid in reducing tomato scion water loss during graft healing, enhancing survival. Objective 2: To integrate discovery-based, applied and on-farm research to optimize field production outcomes. The implementation of this work included a number of geographic areas with diverse horticultural, disease and market challenges and was coordinated by the tomato and cucurbit production WGs. With regard to tomatoes, UFL conducted 2 grafting tomato trials planted in South FL to manage Fusarium crown rot (FCR). Although there was a history of the disease in the field, there was low FCR incidence (<3%) and grafting offered no advantage in the absence of FCR pressure. Of the grafted tomato plants, 21% of the plants produced suckers, which were removed. The FL-USDA-ARS program completed 4 collaborative on-farm field, 1 microplot and 7 greenhouse trials. On-farm trials conducted on the use of Tomato yellow leaf curl virus (TYLCV)-resistant hybrids used as rootstocks for heirloom tomatoes demonstrated grafted plants slowed the impact of virus infection on early yield, but did not result in scion resistance to the virus. A series of experiments evaluated rootstock effects in fields with naturally occurring populations of parasitic nematodes. VaTech conducted 3 field experiments and identified a core group of rootstocks that have good resistance to both bacterial wilt (BW) and root-knot nematode. OSU completed 6 studies focused on grafting methods, pre- and post-grafting environmental effects on grafted plant vigor, the genetic and environmental basis of rootstock-scion compatibility, and grafted plant management and performance (crop nutrient and water management and plant density effects in organic and conventional and field and high tunnel systems). NCSU conducted 3 research station experiments and 4 on-farm research (OFR) projects focused on management of BW and Verticillium wilt (VW; race 2). Thirteen rootstocks evaluated for BW resistance identified useful resistance. On-farm projects led one grower to plant 20 acres of grafted plants and OFR documented grafted plants reduced BW from 40% in the controls to 0 to 7%. Selected rootstocks from OSU and commercial sources suppressed VW incidence in other OFR. A segregating population of over 140 tomato lines for BW resistance was evaluated and QTLs are being mapped. The Cucurbit Production WG coordinated a series of local and regional experiments. Clemson grafted seedless watermelon onto selected rootstocks and found improved control of Fusarium wilt. USDA-ARS performed 3 greenhouse trials on 2 experimental melon rootstocks for susceptibility to 4 important root-knot nematode species including Meloidogyne arenaria, M. incognita, M. javanica, and M. floridensis. No differences were found in total nematode J2 isolated from roots among the rootstocks tested but M. arenaria was found in higher numbers in roots than M. incognita and M. floridensis. With regard to adapting crop production systems (Obj2.2) UFL and NCSU conducted tomato planting density trials under organic or conventional production. Data suggest plant density can be reduced for plant cost savings. In the UFL organic field with root-knot nematode infestation, grafting with the two rootstocks significantly reduced root galling. Clemson found grafted watermelon planted at 4-foot in-row spacing produced the same yield as the standard 3-foot in-row spacing but NCSU did not observe a density benefit with grafted melons (Athena). They also conducted nutrient and water use efficiency studies (NUE; WUE) with grafted watermelons and melons. Increased NUE and WUE were not observed but irrigation methods were optimized. NCSU conducted 2 experiments to optimize NUE with watermelon and tomato grafted plants. Data is being assembled. A series of experiments were performed comparing grafted specialty melons to non-grafted controls and benefits were not observed in land with no biotic or abiotic stressors. Objective 2.3: Grafting effects on fruit quality: NCSU tested tomato rootstock combinations on fruit quality and carotenoids. No clear effects of grafting or N level were found for fruit composition and quality parameters. Grafted watermelon was found to have elevated amounts of lycopene (10-20%) compared to fruit from non-grafted plants. Grafted fruit held in the field on the vine for 7d past ideal ripeness were still of acceptable pH, soluble solids, and lycopene content. . Lycopene content decreased and pH increased in fruit held 14d past ideal ripeness. In fresh cut cubes prepared from these watermelons, lycopene decreased 10-20% in cubes held at 3 C for 14d. Grafting did not impact tomato fruit shelf life. Fruit used to prepare fresh cut cubes were firmer when from grafted watermelons. A series of fruit quality and sensory evaluations were performed at UFL and OSU and data is being compiled. Objective 3: To evaluate economic and social metrics to guide the direction of emerging grafting technology advancements: UFL performed economic analysis of grafted tomato production and showed that the increase in marketable fruit yield generated significant gross returns to offset costs associated with the use of grafted tomato transplants resulting in higher profitability compared with non-grafted tomato. Likewise, NCSU developed production budgets for field conventional, multi-bay tunnel conventional, field organic and high tunnel organic tomato production systems. Partial budget analysis was used to demonstrate economic viability of grafting in each system. Because of the variability in potential individual scenarios, decision matrix methodology and sensitivity analysis were applied to aid the decision making process. Objective 4: To translate outcomes and facilitate the application of grafted plants as a significant tool in vegetable crop production: OSU provided significant leadership for the Extension and Educational WG activities and advancing the project’s website: (vegetablegrafting.org). The WG coordinated the development of 2 commercial rootstock variety tables. The WG with OSU leadership published or coordinated the development of 4 articles in trade publications, each reaching more than 30,000 readers and published 4 e-Newsletter articles, each reaching an average of 2,000 subscribers. Multiple workshops, presentations and outreach publications were achieved (see below).

Publications

• Type: Journal Articles Status: Published Year Published: 2013 Citation: Ling, K.-S., A. Levi, S. Adkins, C.S. Kousik,G. Miller, R. Hassell, and A. Keinath. 2013. Development and field evaluation of multiple virus-resistant bottle gourd (Lagenaria siceraria). Plant Disease 97:1057-1062
• Type: Conference Papers and Presentations Status: Published Year Published: 2012 Citation: Rivard, C.L., O. Sydorovych, R.M. Welker and F.J. Louws. 2012. Grafting as an integrated pest management technique for soilborne disease management of tomato. Proc. of the Int. Res. Conf. on Methyl Bromide Alternatives and Emissions Reduction. 69/1-69-3
• Type: Conference Papers and Presentations Status: Published Year Published: 2012 Citation: Rivard, C.L., O. Sydorovych, S. OConnell, M.M. Peet and F.J. Louws. 2012. An economic analysis of two grafted tomato transplant production systems. Proc. of the Int. Res. Conf. on Methyl Bromide Alternatives and Emissions Reduction. 71/1
• Type: Conference Papers and Presentations Status: Published Year Published: 2012 Citation: Rosskopf, E.N., N. Kokalis-Burelle, S. Adkins, J.C. Hong, C. McKenzie, J. Gibbons, and N. Roe. 2012. Grafting heirloom tomatoes for increased plant vigor and virus tolerance. Proc. of the Int. Res. Conf. on Methyl Bromide Alternatives and Emissions Reduction. 55
• Type: Conference Papers and Presentations Status: Published Year Published: 2012 Citation: Kokalis-Burelle, N. and E.N. Rosskopf, J. Gibbons. 2012. Effects of grafted Heirloom tomatoes on parasitic nematode populations in an organic production system. Proc. of the Int. Res. Conf. on Methyl Bromide Alternatives and Emissions Reduction. 56
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Sydorovych, O., C.L. Rivard, S. OConnell, C.D. Harlow, M.M. Peet, and F.J. Louws. 2013. Growing organic heirloom tomatoes in the field and high tunnels in North Carolina: comparative economic analysis HortTechnology 23:227-236
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Keinath, A. 2013. Susceptibility of cucurbit rootstocks to Didymella bryoniae and control of gummy stem blight on grafted watermelon seedlings with fungicides. Plant Disease 97:1018-1024
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Djidonou, D., Z. Gao, and X. Zhao. 2013. Economic analysis of grafted tomato production in sandy soils in Northern Florida. HortTechnology 23:613-621
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Djidonou, D., X. Zhao, E.H. Simonne, K.E. Koch, and J.E. Erickson. 2013. Yield, water-, and nitrogen-use efficiency in field-grown, grafted tomatoes. HortScience 48:485-492
• Type: Journal Articles Status: Published Year Published: 2012 Citation: Barrett, C.E.. X. Zhao, C.A. Sims, J.K. Brecht, E.Q. Dreyer, and Z. Gao. 2012. Fruit composition and sensory attributes of organic heirloom tomatoes as affected by grafting. HortTechnology 22:804-809
• Type: Journal Articles Status: Submitted Year Published: 2013 Citation: Meng, C., D. Xu, Y. Son, C. Kubota, M. Lewis, R. Tronstad. 2013. An integrated simulation and AHP approach to vegetable grafting operation design. Computers and Electronics in Agriculture (submitted)
• Type: Other Status: Published Year Published: 2013 Citation: Keinath, A. and Hassell, R. 2013. On-farm evaluation of grafted seedless watermelon for control of Fusarium wilt race 2. Plant Disease Management Reports 7:V033
• Type: Theses/Dissertations Status: Accepted Year Published: 2013 Citation: IOTT, MEAGAN COLLEEN. 2013. Utility of Grafting and Evaluation of Rootstocks for the Management of Verticillium Wilt in Western North Carolina.

Progress 09/01/11 to 08/31/12

Outputs
OUTPUTS: Objective 1: Significant progress was made to develop a decision support system for propagators to plan, design and optimize grafting propagation operations and supply chains. Projects also advanced new propagation and distribution methods. Use of un-rooted grafted cuttings was evaluated for tomato and watermelon for post-treatment growth and development as affected by healing duration and shipping temperature. Tomato graft union strengths were evaluated as impacted by cutting angle. Progress was made to prevent re-growth of the rootstocks (RS) after grafting melons by refining a patented fatty alcohol application method. Transplant hygiene and quality methods were advanced by evaluation of efficacy and phytotoxicity of disinfectants, management of grafted cucurbit seedling foliar diseases, and virus transmission studies. Objective 2: Available and emerging RS were evaluated for disease resistance. Tomato: Bacterial wilt (BW) resistance was evaluated in 3 States using multiple RS and integrated with other IPM tactics such as use of foliar application of Actigard and soil fumigation. Regional experiments evaluated the effectiveness of grafting determinate and heirloom scions onto RS to manage root knot (RKN) or spiral nematodes and Verticillium wilt. Cucurbits: Cucumis metulifer was tested as a new RS for RKN control in specialty melons under both organic and conventional production. The new seedless watermelon cultivar Fascination, resistant to Fusarium oxysporum f. sp. niveum (FON) race 1 but susceptible to race 2, was evaluated in a field naturally infested with FON race 2. Work was completed to integrate grafting into current production systems. Florida 47 tomato was grafted onto two interspecific hybrid RS to optimize drip irrigation regimes and nitrogen (N) rates. Yield was evaluated on commercially sized tomato plots using Aloha, Camel, Multifort, BB, and Hawaii-7997 RS and FL-91, Biltmore and Fl-47 scions. Tomato plant density and soil history/amendment options were assessed in high tunnel systems and RS impacts on irrigation needs was evaluated in northern field systems. Seventeen melon cultivars were evaluated in 3 locations to determine grafting impacts on yield and quality with various in-row spacing. Several experiments evaluated nutrient demands as impacted by RS*scion combinations. Multiple regional trials evaluated utility of grafting on yield complemented with assessment of parameters such as soluble solids content, pH, firmness, SSC, pH, and lycopene content. Consumer sensory analysis was conducted to examine the influence of RS selections on taste and flavor of honeydew melon Honey Yellow and Galia melon Arava for firmness and flavor. Objective 3: Baseline budgets for high tunnel, organic and conventional tomato and cucurbit production systems of various scales were initiated. Objective 4: Over 140 extension activities were organized to translate novel research and available knowledge in 15 different States and 2 international countries. A website graftvegetables.org was created. Over 48 private enterprises were engaged in the development, evaluation and extension of grafting projects and outcomes. PARTICIPANTS: data is forthcoming TARGET AUDIENCES: This project is scale neutral and has a broad range of target audiences. The focus is on stakeholders who seek to advance the capacity of producing grafted plants, who use grafted plants in field-based systems and who disseminate knowledge gained. Thus, we have linked with individuals and major companies that seek to advance the use of grafted plants in the home garden. We also work with seed companies, technology companies and transplant production companies of various size and experiences that focus on commercial vegetable production systems. They provide capacity for producing and marketing grafted plants. Target audiences that use grafted plants include organic and conventional growers in high tunnel and open field systems across the USA. Finally, we work with key industry publications with local, regional or national audiences to disseminate information. Our efforts are consistent with traditional, modern and progressive educational, outreach and extension tools. For example, over 75 powerpoint presentations to diverse audiences in up to 15 States have been delivered. Multiple field days that draw a diverse audience of growers and professionals have been conducted in several States. Up to 10 workshops in several States have been conducted to show how to graft and how to manage grafted plants. These have been complemented with 16 video and/or audio products or webinars. We have developed a website with multiple names all pointing to the same direction such as graftvegetables.com and graftvegetables.org. We utilize the popular press extensively with 7 trade articles published. We engage growers by doing on-farm and participatory research. We also have engaged 48 private companies, farm families or other stakeholders as they directly invest in the process of discovery and implementation of grafting technologies and information. Finally, we advance the science of the industry through peer reviewed publications and professional presentations at scientific meetings. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Objective 1: The decision support systems and models suggest the cost per plant could be as low as 8 cents; the increase of technology, automation, and size afford economies of scale estimated at 50% cost savings. In propagation experiments, the best healing duration was 3 to 7 days for tomato and 5 to 7 days for watermelon. Lower temperature prevented quality deterioration. Most members of solanaceae and cucurbitae are storable for 4 weeks at 10 and 12oC. An application rate of 6.25% fatty alcohol solution provided optimal control of RS regrowth while causing the least amount of damage to the seedlings. The highest pulling force was recorded when grafting was done at 30 degrees angle. Virkon S, Kleen Gro, and Clorox where not phytotoxic but Physan 20 and hydrogen peroxide caused injury. Specific recommendations to manage powdery mildew and gummy stem blight were developed. Objective 2: RS significantly decreased in BW and RKN incidence in multiple experiments and in most cases significantly increased yield. Selected RS decreased VW severity. Grafting of Purple Calabash heirloom tomato scions onto Tygress RS reduced the number of RKN juveniles isolated from roots compared to Purple Calabash grafted onto Matts Wild Cherry RS. C. metulifer decreased RKN galling compared with nongrafted Honey Yellow and decreased second-stage juveniles in an organic field, decreasing risk to subsequent crops. Bottlegourd RS Emphasis and Macis and the hybrid squash RS Strong Tosa and Carnivor reduced FON incidence in Fascination watermelons and increased yield. Scion*RS effects emerged in the program. For example, Aloha and Multifort tomato RS increased yield 22% or more compared to FL-91 controls, Hawaii 7997 tended to decrease yield. Differential responses were also observed in organic vs. conventional systems and in one case, a specific combination decreased flower cluster numbers. In cucurbits, grafted Athena melons had less netting or were slicker than those not grafted but typically produced an earlier harvest with more or less yield, depending on the evaluation site. Grafting exhibited negative effects on consumer perceived sensory attributes of Arava melon fruit, while taste test ratings were similar between nongrafted and grafted Honey Yellow . Husbandry differential interactions were also observed. In tomato grafting with vigorous interspecific RS significantly increased tomato yields and improved irrigation water and N use efficiency in FL; grafted plants exhibited greater response to increasing N rates. In contrast, grafted watermelon plants did not respond differently to fertigation treatments vs non-grafted plants. With regard to fruit quality and sensory parameters, more differences were observed due to rootstock effects in watermelons compared to tomatoes. For example, Carnivor and Super Shintosa most consistently yielded fruit with highest lycopene and soluble solids in watermelons and Eastern U.S., seedless watermelon scions gave best fruit quality when grafted to interspecific squash hybrid RS. Objective 3 outcomes are forthcoming and objective 4 resulted in extensive outreach and training benefits to diverse audiences.

Publications

• Barrett, C.E., X. Zhao, and R. McSorley. 2012. Grafting for root-knot nematode control and yield improvement in organic heirloom tomato production. HortScience 47:614-620.
• Barrett, C.E., X. Zhao, and A.W. Hodges. 2012. Cost benefit analysis of using grafted transplants for root-knot nematode management in organic heirloom tomato production. HortTechnology 22:252-257.
• Bausher, M. 2012. Graft angle and its relationship to tomato plant survival. HortScience. (in press).
• Bausher, M. 2012. Serial Transmission of plant viruses by cutting implements during grafting. HortScience (in press).
• Djidonou, D., X. Zhao, E.H. Simonne, K.E. Koch, and J.E. Erickson. 2012. Yield, irrigation water and nitrogen use efficiency of field grown grafted tomato with drip irrigation. HortScience. (Accepted)
• Iott, M. , J. G. Driver, F. J. Louws. 2012. Utility of grafting to manage Verticillium wilt of tomato and extension education of grafting in North Carolina. Phytopathology 102:S299. Iott, M., Welker, R.M., Rivard, C.L., and Louws, F.J. 2011. Potential role of grafting as a method to manage Verticillium dahliae race 2 in tomato production systems. Phytopathology 101:S79. Keinath, A. P., Baccari, G. V., and DuBose, V. 2011. Controlling gummy stem blight in the greenhouse on watermelon seedlings grafted onto cucurbit RS. Phytopathology 101:S89.
• Keinath, A. P., and DuBose, V. B. 2012. Controlling powdery mildew on cucurbit RS seedlings in the greenhouse with fungicides and biofungicides. Crop Protection 42:338-344.
• Louws, F.J. 2012. IPM diversification: Advancing the science and practice of grafting tomatoes to manage soilborne pathogens. Phytopathology 102:S78. Louws, F.J. Overview of vegetable grafting as an IPM tactic in US vegetable production. HortScience 47: S121. McAvoy T, Freeman J, Rideout S, Olson SM, Paret ML. 2012. Grafting using hybrid RS for management of bacterial wilt in field tomato production. HortScience 47(5): 621-625.
• Meng, C., D. Xu, Y.-J. Son, and C. Kubota. 2012. Simulation-based economic feasibility analysis of grafting technology for propagation operation. Proceedings of the 2012 Industrial and Systems Engineering Research Conference, Orlando, May 2012