Evaluation of Resistant Rootstocks for Grafting Tomato (Solanum lycopersicum) Variety Thilina to Manage Bacterial wilt

Abstract

Bacterial wilt (BW) is an economically important, soil-borne disease of tomato (Solanum lycopersicum) that can cause severe yield losses up to 100%. Although the tomato variety Thilina has desirable fruit traits like thick pericarp, it shows only moderate bacterial wilt resistance. Grafting Thilina onto BW-resistant rootstocks offers an eco-friendly strategy for disease management. This study evaluated the BW resistance of Thilina grafted onto resistant rootstocks. Lanka Sour and T245 tomato varieties, Pepino (Solanum muricatum Aiton), and eggplant (Solanum melongena L.) cv. Padagoda were used as bacterial wilt–resistant rootstocks for wedge grafting onto the tomato variety Thilina. Non-grafted Thilina plants served as the control. All plants were transplanted in a field that had been heavily contaminated with the bacterial wilt during the previous cropping season. Wilting incidence, vegetative growth and fruiting parameters were evaluated. Data were analyzed using one-way analysis of variance (ANOVA) in SAS statistical software, and means were separated using Duncan's multiple range test at p≤0.05. A significantly lower wilting percentage was observed in plants grafted on Lanka Sour (0%), Padagoda (3.13%), and Pepino (4.17%) compared with the non-grafted Thilina (37.5%) and T245 (9.38%), at 60 days after transplanting. The greatest plant height was recorded in rootstock Padagoda, followed by T245 and Lanka Sour. The maximum number of primary branches was observed in rootstock Lanka Sour, followed by Padagoda and T245. The highest number of fruits was produced by Thilina grafted onto Lanka Sour. Number of fruits on T245, non-grafted and Padagoda plants were statistically similar, whereas grafting onto Pepino rootstock resulted in the lowest fruit yield. The study findings indicate that Lanka Sour, Padagoda, and Pepino rootstocks effectively reduced bacterial wilt in Thilina variety. Lanka Sour is recommended for complete resistance and optimal yield. Padagoda enhances plant growth whereas Pepino reduces yield despite its disease suppression.