The effects of grafting on Tomato (Solanum lycopersicum L.) yield and quality

Masters DissertationF1 Hybrid tomato cultivars are preferentially grown in Tanzania due to their high yield but are susceptible to some common biotic stresses. Grafting tomato onto compatible and resistant rootstocks has a greater potential to overcome soil borne diseases, abiotic stresses, improve growth, yield and fruit quality. However, in Tanzania there is limited information regarding grafting between F1 hybrid tomato cultivars and selected eggplant rootstocks. Therefore, the objectives of this study were: (1) to determine graft success between selected eggplant rootstocks and selected F1 hybrid tomato cultivars, (2) to evaluate the effect of selected eggplant rootstocks on plant growth, yield and fruit quality of F1 hybrid tomato cultivars and (3) to determine profitability of grafted F1 hybrid tomato cultivars. Experiments were laid out in a Randomized Complete Block Design with 3 replications. Tomato cv. Assila, Monica and Tengeru 97 as a control were grafted onto rootstocks EG190, EG195 and EG203 and transplanted in the field. Data for specific objectives 1 and 2 were subjected to Analysis of Variance using GenStat version 14 software (VSN International, UK). Treatment means were separated by Tukey’s Test at P≤0.05 whereas profitability data were analysed descriptively. Results revealed significantly low (p = 0.001) field grafting success after transplanting, reduced growth (p = 0.001), low yield (p = 0.001) and low profitability for grafted Assila and Monica in comparison to ungrafted Assila, Monica and grafted Tengeru 97. Conversely, grafting improved fruit taste based on enhanced total soluble solids (TSS) in rootstock/Assila and rootstock/Monica. Overall, tomato cv. Assila and Monica should not be grafted onto these eggplant rootstocks due to low graft success, low yield and low profitability. Further studies are required to identify rootstocks that are compatible with, and vigorous enough for growth, fruit quality and profit improvement.Division of Product Development, Training and Quality Assurance (DPDTQA