Evaluating Sustainable Alternatives of Rootstock Selections in Grafted Tomatoes to Enhance Yield Potential in High Tunnel and Field Production
During the 2016 season,100 tomato transplants from each variety were raised to produce "saved seeds" from the plants showing the greatest disease resistance that also produced tomatoes true to variety. The three open pollinated (non-hybrid) varieties used were: Rutgers, Roma, and Large Red Cherry. In the 2015 season, when the initial 100 transplants were grown, between 13-27% of plants were eligible sources for saving seeds. The seeds used in the 2016 season were from the seeds saved from the 2015 season.
The 100 plants of each variety grown from seeds saved from parent plants showing improved disease resistance performed better in the 2016 season. Roma had 83% of plants showing no sign of disease, Rutgers had 76%, and Red Cherry had 56%. All the plants showing improved disease control had tomatoes remaining true to variety. The plants from which we harvested the earliest tomatoes were marked with ribbon and the seeds from these plants that also showed disease resistance were saved for the upcoming 2017 season. The 2015 and 2016 seasons were wetter than average. Higher disease pressure was observed in these open pollinated tomato varieties grown under organic certification standards.
The upcoming 2017 season will use the seeds saved from Rutgers, Roma, and Red Cherry varieties as the rootstock in the grafting studies. The variety "Red Cherry" will be added to the original proposal because the large stem has produced a superior graft when the heavy fruit caused some graft failure with rootstocks using "Roma".
No other changes to the original proposal is anticipated for this final season.
A significant improvement was observed from the 2015 season to the 2016 season from seeds saved. The variation of plants in open pollinated varieties such as Red Cherry, Roma, and Rutgers seems to transfer the improvements on disease resistance to their offspring. If farmers can retain the seeds from plants showing the greatest disease resistance to pressures found in their particular environment, these plants may provide a sustainable root stock option for grafting scion tomato varieties with little genetic disease resistance. If successful, farmers can save seeds from both root stock varieties and scion varieties to produce healthy tomatoes through grafting rather than relying on chemical-based treatments for diseases.