Potential of host resistance as an important tool in the management of bacterial wilt in tomatoes

Abstract

Bacterial wilt is a major bacterial disease that impacts tomato (Solanum lycopersicum) production in Tanzania. The disease is caused by members of soil borne Ralstonia solanacearum with complex pathogen variability and a wide host range complicating its management. We established the use of tomato lines MT56 and WG120 and eggplant line EG190 from the pre-screening experiment to evaluate resistance against Ralstonia pseudosolanacearum strains collected from key tomato-growing regions of Tanzania. Among the three lines resistant to bacterial wilt infection, MT56 and EG190 were selected as rootstocks for grafting with the susceptible tomato variety Moneymaker. Grafted seedlings were challenged with a mixture of strains that were previously used in the evaluation of rootstocks. Grafted seedlings had significantly reduced bacterial wilt incidence compared to self-grafted Moneymaker. Bacterial wilt disease progress as measured by area under disease progress curves (AUDPCs) varied significantly among rootstock/scion combinations (P=0.0190). The area under the disease progress curve values was consistently low for self-grafted rootstock and rootstock/scion grafted seedlings. This study demonstrates the potential of using host resistance as an efficient and environmentally friendly management option for bacterial wilt disease.