Screening of Tomato (Solanum lycopersicum L.) Genotypes for Tolerance to Bacterial Wilt Caused by Ralstonia solanacearum Under Screenhouse Conditions
Abstract
Bacterial wilt caused by Ralstonia solanacearum is one of the most destructive soil-borne diseases limiting tomato production in tropical regions. The identification of tolerant genotypes remains the most sustainable strategy for managing the disease, particularly in endemic zones of South-Western Nigeria. This study evaluated eleven tomato (Solanum lycopersicum L.) genotypes comprising seven NIHORT accessions, one commercial hybrid (F1 Cobra 26), and three local varieties for tolerance to bacterial wilt under controlled screenhouse conditions. The experiment was arranged in a 2 × 11 factorial and laid out in a Randomized Complete Block Design (RCBD) with three replicates. Plants were artificially inoculated using a standardized bacterial suspension adjusted to 2 × 10⁹ CFU ml⁻¹. Disease incidence was calculated as a percentage of symptomatic plants per genotype. Significant differences (p < 0.05) were observed among genotypes for disease incidence and wilting severity. Disease incidence ranged from 16.0% in F1 Cobra 26 to 53.4% in NHTO 0199 under inoculated conditions, with susceptible genotypes exhibiting severe wilting symptoms. On the other hand, selected NIHORT accessions demonstrated comparatively lower disease severity and delayed symptom expression, indicating partial tolerance to R. solanacearum. The findings reveal substantial genetic variability in response to bacterial wilt and highlight the potential of specific improved accessions as candidate materials for breeding and cultivation in wilt-endemic regions. Adoption of tolerant genotypes is strongly recommended as a core component of integrated bacterial wilt management strategies.