Graft compatibility between eggplant rootstocks and hybrid tomato (Solanum lycopersicum Mill.) cultivars

Abstract

Tomato grafting has proven to mitigate some soil-borne diseases and abiotic stresses as well as improve plant growth, yield and fruit quality. However, in Tanzania the graft compatibility between eggplant rootstocks and hybrid tomato cultivars has not yet been explored. Therefore, the objective of this study was to evaluate graft compatibility between eggplant rootstocks and hybrid tomato cultivars grown in Tanzania. The study was conducted at Sokoine University of Agriculture (SUA) Morogoro, Tanzania and the experiment was laid out in a Complete Randomized Design with three replications. Hybrid tomato cv. Assila and Monica were each cleft-grafted onto eggplant EG190, EG195 and EG203 rootstocks, healed for six days in a healing chambers, hardened for seven days under a shade of 30% and later transplanted in the open field. Data were subjected to Analysis of Variance using GenStat v.14 statistical package (VSN International, UK) and treatment means were separated based on Tukey’s Test at P≤0.05. Results reveal that grafting eggplant EG190, EG195 and EG203 rootstocks with hybrid tomato cultivars significantly led to partial incompatibility based on higher incidence of adventitious roots at the graft union (p=0.001), plant wilting (p=0.001) and death (p=0.001) after transplanting in the field. Similarly, grafting these eggplant rootstocks significantly reduced plant height (p=0.001) and stem diameter (p=0.001) of tomato cv. Assila and Monica in comparison to ungrafted controls. Conversely, grafting these eggplant rootstocks significantly advanced flowering (p=0.008) and fruit harvest (p=0.001) of tomato cv. Assila and Monica compared to ungrafted controls. Further studies are required to determine rootstocks that are vigorous enough to carry the scions of hybrid tomato cultivars for improved graft compatibility and plant growth.

Keywords: Grafting, Flowering, Harvesting, Adventitious roots, Assila, Monica