Microclimate and Scion Leaf Removal to Improve the Success of Grafted Tomato Seedlings

摘要

The utilization of grafted tomato (Solanum lycopersicum) plants in the United States shows significant promise, particularly as intensively managed production systems like high tunnels and greenhouses become more popular. However, the availability of grafted plants in the United States is currently a major barrier and a large portion of farmers who would like to use grafted plants would prefer to propagate their own. The objectives of this study were to determine how healing chamber design affects graft survival and microclimate, and to investigate how scion leaf and shoot removal affects graft survival in various healing chambers. Similar experiments were repeated at two locations in Kansas and a split-plot, randomized complete block design (RCBD) was used in each, with three and four replications being conducted over time at each of the locations. Five chamber treatments were tested including a negative control (none) as well as shadecloth alone, white vinyl mesh, polyethylene film and shadecloth, and polyethylene film with shadecloth and a cool-mist humidifier. No statistically significant effects of chamber design were seen on grafted plant success. However, microclimate data from the various healing chambers offer valuable data toward determining the best management practices for grafted plants. Shadecloth alone showed significant promise as this covering provided cooler temperatures during the afternoon when the healing chambers were prone to excessive heat buildup. Three tube-grafting methods were tested, including standard tube-grafted plants (no leaves removed), leaf removal (LR) plants (approximate to 75% of the leaf surface area was removed from the scion), and shoot removal (SR) plants (the apical meristem and all true leaves were removed). The SR method did not affect graft survival, but the LR method increased grafting success from 78% to 84% and was significant as compared with the other methods (P0.05). The long-term goals of this work are to develop successful propagation systems that can be used by small-acreage growers with limited greenhouse facilities. The data presented here indicate that high-humidity healing chambers (>85% relative humidity) may not be necessary for tomato, and LR can increase the grafting success rate.