Productive and physiological characteristics of tomato plants produced on different rootstocks

Grafting facilitates the management of phytodiseases, especially of soils, but the growth and development of the grafted plant depend on the compatibility with rootstocks. The objective was to evaluate the graft union and survival, the growth characteristics, fruit biometrics, yield and physiological characteristics of the tomato plant ‘Santa Clara’ on five rootstocks. The study was conducted at the Pici Campus of the Federal University of Ceará in Fortaleza, Ceará state, Brazil. The seven treatments were tomato ‘Santa Clara’ ungrafted and self-grafted, or grafted onto cherry tomato ‘Vermelho’, hybrid tomato ‘Guardiao’, eggplant ‘Comprida Roxa’, jiló ‘Comprido Grande Rio’ (Solanum gilo) and cocona (Solanum sessiliflorum). Cleft grafting was used. The growth characteristics evaluated were stem diameter (SD), plant height (PH), and number of commercial (NCF) and total (NTF) fruits. The biometric characteristics of the fruits (diameter-FD, length-FL and average mass-AMF) and productive (commercial-CFM and total-TFM fruit mass) and yield of commercial (YCF) and total (YTF) fruits were estimated per hectare. Physiological evaluations were performed to obtain the internal concentration of CO₂ (Ci), transpiration rate (E), stomatal conductance (Gs), liquid photosynthesis (A), ratio between internal CO₂ and the environment (Ci/Ca) and carboxylation efficiency (A/Ci). The graft union and survival of S. lycopersicum plants was 100% at 10 days after grafting. The number of commercial and total fruits were higher in non-grafted tomato plants. The FD of the plants was higher with rootstocks of the ‘Vermelho’ cherry tomato and ‘Guardião’ hybrid, the CFM and TFM with ungrafted, the AMF and TFM with ‘Vermelho’ cherry tomato and the YCF and YTF with ungrafted and grafting on the ‘Vermelho’ cherry tomato. The tomato plant ‘Santa Clara’ completed its development in rootstocks and, therefore, they are compatible with this plant. The production of tomato fruits was higher with grafting on the ‘Vermelho’ cherry tomato with diameter and productivity similar to those of the ungrafted plants, indicating that this tomato cultivar can be used as rootstock.