Tomato Grafting: Developing Grower Recommendations for the Great Plains and Enhancing Our Understanding of the “Rhizobiome”

Tomato Grafting: Developing Grower Recommendations for the Great Plains and Enhancing Our Understanding of the “Rhizobiome”

Summary

This project was very successful in 2015 and all of our major performance targets were obtained, if not exceeded as they were described in the proposal. We successfully conducted seven research trials, four of which were on commercial farms. Lani Meyer successfully analyzed the field trial data and developed the 2013 and 2014 data into her M.S. thesis, which she successfully defended in April 2016. We expect to combine data collected in 2015 for scientific publication. Ravin Poudel (PhD student) completed genomic rhizobiome data analysis from 2013 and 2014 and continued sampling in field trials conducted in 2015. We were very successful at communicating the results of our work to scientific and grower audiences in eight states in 2015 as well as Washington DC. Education efforts included a hands-on grafting workshop, a commercial vegetable field day, and the grafting clinics held at the Great Plains Growers Conference in January 2015 as well as the the Great Lakes Expo in 2015 (described below). All of these venues were very successful at making changes in knowledge and behavior of growers.

Objectives/Performance Targets

The objectives of this project are (1) to identify rootstocks that improve productivity and reduce disease losses in the Great Plains through a series of on-farm and university research trials, (2) to determine optimum grafting/healing conditions that reduce risk of crop failure and increases the successful implementation of grafting for small-scale growers, (3) evaluate the effects of rootstocks on rhizosphere microbial communities; and (4) disseminate grafted propagation methods as well as the results of our research through an integrated extension program. We will perform a series of replicated field studies including at least two on-farm trials per year that evaluate tomato rootstocks for their performance in regards to soilborne disease, crop yield, and marketability. Specific outputs include (1) Extension publications, field tours, web materials, videos, and hands-on workshops; (2) Research journal publications, presentations, and teaching materials. Short-term outcomes include (1) Increased grower knowledge for grafting implementation; (2) Increased scientific community understanding of rhizobiome interactions. Mid- and Long-term outcomes include: (1) Changes in grower behavior related to propagation of grafted plants and rootstock selection; (2) Increased local availability of grafted plants; (3) Further scientific exploration of grafting and rhizobiome interactions, in support of fuller understanding of mechanisms of disease resistance and increased vigor. This proposal builds on a project that is supported by the Ceres Trust Organic Research Initiative.

Accomplishments/Milestones

• Performed four on-farm high tunnel and/or open-field research trials that evaluated numerous rootstocks for growers in the North Central Region at commercial farms.
• Performed three high tunnel and/or open-field research trials that evaluated numerous rootstocks for growers in the North Central Region at KSU research stations.
• Sampled roots at OHREC, Common Harvest, Gibbs Road Farm, and Gieringer’s Orchard for rhizobiome work, which is currently undergoing analysis and write-up.
• All data from research trials was analyzed and presented at venues including:
  • Great Plains Growers Conference in St. Joseph, MO (Rivard, Kennelly, Meyer)
  • National Grafting Symposium in Savannah, GA (Meyer, Poudel)
  • Horticulture Sciences Day at Johnson County Community College (Overland Park, KS) (Meyer)
  • Truman State University Agriculture and Biology Seminar Series in Kirksville, MO (Rivard)
  • MOSES conference in La Crosse, WI (Poudel)
  • Grafting workshop with hands-on grating activity in Lawrence, KS (Meyer, Rivard)
  • Lincoln University High Tunnel Conference in Independence, MO (Rivard)
  • Phytobiomes Conference in Washington DC (Garrett, Poudel)
  • American Phytopathological Society (APS) conference in Pasadena, CA (Garrett, Kennelly, Poudel)
  • American Society for Horticulture Science (ASHS) conference in New Orleans, LA (Rivard, Meyer)
  • Lincoln University In-Service Education for Extension Educators in Jefferson City, MO (Rivard)
  • Texas High Tunnel Growers Conference in College Station, TX (Rivard)
  • Two grafting classes (guest lecture and lab) delivered at KSU in HORT 350 – Plant Propagation in Spring 2015 (Meyer, Rivard)
  • OHREC public field day (Rivard, Meyer)
  • OHREC commercial vegetable growers field day (Rivard, Kennelly, Poudel, Meyer)
  • Florida Genetics Symposium in Gainesville, FL (Poudel, Garrett)
  • National Grafting Symposium in Grand Rapids, MI (Meyer, Rivard)
• Analyzed data and developed two scientific publications as part of Lani Meyer’s M.S. thesis (successfully defended April 2016).
  • “Leaf Removal Reduces Adventitious Root Formation and Plant Growth of Grafted Tomato” (expect to be submitted to HortTechnology in June 2016)
  • “Grafting With Vigorous Rootstocks to Increase Tomato Productivity in High Tunnels in the Central United States” (currently being combined with 2015 field data for submission to HortScience)
  • Data is currently being integrated into an extension publication.
• Performed DNA extraction, sequencing, and bioinformatics analysis of rhizobiome data including network analysis as part of Ravin Poudel’s PhD Dissertation (to be completed in 2016).
• Developed drafts of two extension publications (overview of tomato grafting, healing chamber management guide) that will be published in 2016.
• Scientific Publications:

• O. Rysin, C.L. Rivard, and F.J. Louws. 2015. Is vegetable grafting economically viable in the United States: Evidence from four different tomato production systems. Acta Horticulturae 1086:79-86.
• S.A. Masterson, M. Kennelly, R.R. Janke and C.L. Rivard. 201X. Effect of seedling shoot removal on the yield of grafted tomatoes in high tunnels in the central United States. Acta Horticulturae (in press).

                 o  C.L. Rivard, L. Meyer, E.D. Pliakoni, and M. Kennelly. 2015. The effects of leaf          removal on adventitious root formation and plant growth of grafted tomatoes. HortScience. (Abstr)

• Poudel, A. Jumpponen, M. Kennelly, C. Rivard, and K. Garrett. 2015. Rhizobiome responses to new tomato rootstock systems. Phytopathology 105:S4.113

Impacts and Contributions/Outcomes

• We are continuing to build a strong data set with this project that will be very valuable for growers in relation to rootstock selection. Two rootstocks that we evaluated were not suitable for this area while an additional 3-4 are showing consistent benefits across three years of data, even where little disease pressure is evident. This is extremely important information for growers and has been delivered effectively in order to institute change in knowledge and behavior.
• During January 2015, we coordinated a “Tomato Grafting Clinic” at the Great Plains Growers Conference in St. Joseph, MO. Within the clinic was a self-guided tour related to grafted propagation, rootstock selection, and economic data. This included printed slides, poster presentations, all tools and supplies needed for grafting, several examples of healing chambers, and numerous videos, which looped on-screen for participants to watch. We also included plants and training where participants could graft their own plants. This was a new approach, which relied on active learning by participants.
• In December 2015, we took the “Tomato Grafting Clinic” to the Great Lakes Expo, a much larger fruit and vegetable growers conference (>3000 participants) that occurs annually in Grand Rapids, MI. The clinic was a collaboration with Ohio State University as part of a larger SCRI CAP project on grafting that we are part of and also supported the National Grafting Symposium, which was held just prior to the growers conference. While there, Lani Meyer presented the results of her research in addition to teaching farmers that visited the clinic throughout the conference. Cary Rivard also participated in the conference and helped to coordinate and deliver and in-service training that was provided to ~30 extension agents from across the country that have a particular interest in grafting. Two farmers (Josh Smith and Craig Marklinger) from the Gibbs Road Farm were in attendance as well. Although this event was not directly supported by this NCR-SARE project, much of the information delivered by the KSU team was developed through the support of this project.
• One of the Grower-collaborators on this project spoke at the National Grafting Symposium in Savannah, GA, and his interaction with the project has established him as a leader in this area. After his experiences at the symposium, he has established better contacts for information about grafting nationally and has already networked with vendors to identify a source of grafted plants. Similarly, the National Grafting Symposium that was held in December 2015 was attended by on-farm collaborators from the Gibbs Road Farm (Cultivate Kansas City).
• One grower in Kansas that has recently seen the results of our work (Dan Kuhn, Courtland, KS) planted ~3000 grafted plants in his high tunnels. Numerous other growers are experimenting with smaller plantings.
• Our research with the propagation of grafted plants over the past three years has made a strong impact on how we grow grafted plants at the research station. In the spring of 2015, we changed our “typical” grafting procedures to match what our research results were showing us. In particular, the experiments that were conducted in spring 2014 and as part of this project gave us useful insight into the effect of leaf removal and healing chamber management. In 2016, we continued to further this effort and are still using techniques learned through the experiments we conducted in the first year of the project. This trend has been communicated to growers and propagators and we expect that it will make significant impact for growers to see that we our changing our own propagation methods.

Collaborators: