Graft Angle and Its Relationship to Tomato Plant Survival

Abstract

Growing transplants that can withstand the rigors of open-field production is imperative for the successful adoption of grafting in large-scale commercial fields and especially for those who seek to adopt this technology as an alternative to soil fumigation. This study examines the relationship of tensile strength to graft angle and plant survival. Tomato (Solanum lycopersicum) seedlings of ‘FL-47’ and ‘Rutgers’ were used as scions on ‘Roma’ rootstock under greenhouse and healing chamber conditions. Scions were grafted at angles of 20°, 45°, and 70°. After a period of 10 days, the plants were severed near ground level and subjected to pull force analysis. Pull force of the graft increased significantly with the increased graft angle. Pull force between the 20° vs. 70° angles increased significantly as well as those of 45° vs. 70° grafts (P ≤ 0.001). Increase in graft angle resulted in greater survival of grafted plants from 79% (20°), 81% (45°), and 92% (70°). Fifteen commercial rootstocks grafted at 70° had survival percentage rates between 97% and 100%. These studies demonstrate that the angle can significantly impact graft integrity and plant survival.