Abstract:
Cultivation of solanaceous vegetables such as eggplant and tomato is severely affected by bacterial wilt in the coastal regions of India. The causal agent Ralstonia pseudosolanacearum is soilborne bacterium, highly diverse, and able to survive in soil for many years without a host. Five bacterial wilt resistant eggplant (Solanum melongena) rootstock lines were evaluated by challenge inoculation and were found to show different levels of wilt incidence. Grafts of eggplant made on two rootstocks (S0004 and Surya) recorded reduced incidence of bacterial wilt (10 to 40 percent) during greenhouse evaluation while in nongrafted seedlings, the wilt incidence was 80 to 100 percent. Field evaluation of eggplant grafts made on Solanum torvum (Turkey berry), S0004, and Surya reduced the incidence of bacterial wilt compared to nongrafted seedlings. The lowest wilt incidence (0 and 15-40 percent) was observed in the field evaluations where S. torvum was used as rootstock, while the nongrafted control recorded 93-100 percent wilt. Tomato seedlings grafted on S. torvum, Surya, and S0004 recorded very low bacterial wilt incidence (0 to 15 percent) under greenhouse evaluation while the nongrafted seedlings recorded 80 to 100 percent wilt. Reduced bacterial wilt incidence (23 to 40 percent) was observed in grafts of polyhouse-grown tomato hybrid (GS-600) made on S. torvum while the nongrafted seedlings were severely affected (80 to 100 percent) in evaluation trials conducted for two years. From this study, it is evident that grafting of susceptible eggplant and tomato on resistant rootstocks, viz., S. torvum and Surya, could be a promising strategy in bacterial wilt management.
