Screening of Tomato (Solanum lycopersicum L.) Genotypes for Tolerance to Bacterial Wilt Caused by Ralstonia solanacearum Under Screenhouse Conditions

Identification of novel source and inheritance of resistance to bacterial wilt (Ralstonia solanacearum) in tomato (Solanum lycopersicum L.) for sustainable disease management

Bacterial wilt caused by Ralstonia solanacearum is a destructive disease severely restricting tomato (Solanum lycopersicum L.) productivity in tropical and subtropical regions. The purpose of this study was to identify novel sources of resistance and explicate the inheritance pattern of bacterial wilt resistance in tomato.  A total of 59 genotypes, including open-pollinated lines, hybrids and breeding accessions, were subjected to screening experiments during two consecutive seasons (2022–2023 and 2023–2024) under controlled net house conditions at Centurion University of Technology and Management and natural epiphytotic field conditions at Indian Institute of Horticultural Research - Central Horticultural Experiment Station , Bhubaneswar, India. Disease severity was evaluated using percent disease index (PDI) and area under disease progress curve (AUDPC). The open-pollinated cultivar ‘Utkal Kumari (BT-10)’ exhibited consistent high resistance, with significantly lower AUDPC values (<150 vs >1800 in susceptible checks) and high survival rates (90 %) across environments. Among others, tomato cultivars Arka Samrat, Arka Abhed and JK Desi, demonstrated significant resistance while genotypes such as Pusa Ruby and EW815 were consistently highly susceptible. A segregating F₂ population derived from a cross between resistant ‘BT-10’ and susceptible ‘Pusa Ruby’ exhibited continuous variation in disease response. Chi-square analysis revealed significant deviation from a 3:1 Mendelian segregation ratio (χ² = 72.30, P < 0.01), indicating a quantitative mode of inheritance. These findings highlight the potential of Utkal Kumari and allied resistant lines as donors for resistance breeding and emphasize the need to integrate robust phenotypic screening with molecular approaches for durable and strategic bacterial wilt management in tomato.

Screening of Tomato Germplasm for Resistance to Fusarium Wilt Caused by Fusarium oxysporum f. sp. lycopersici under in vivo Conditions

Fusarium wilt, caused by Fusarium oxysporum f. sp. lycopersici, is a major constraint on tomato production worldwide. The present study was undertaken to evaluate thirty tomato germplasm accessions obtained from the ICAR-Indian Institute of Vegetable Research (IIVR), Varanasi, for their response to Fusarium wilt under field conditions during the 2023 and 2024 cropping seasons at SKUAST-Jammu, Chatha. The thirty germplasm accessions were evaluated under artificial disease pressure, and disease development was assessed through disease incidence, apparent infection rate (r), and area under the disease progress curve (AUDPC), with Pusa Ruby included as the susceptible cultivar. Significant variation was observed among the germplasm accessions in disease development and progression. Based on pooled disease incidence, one germplasm accession was categorised as tolerant (T), two as moderately susceptible (MS), ten as susceptible (S), and seventeen as highly susceptible (HS), whereas no germplasm accession showed resistant (R) or moderately resistant (MR) reactions. The germplasm accessions also exhibited considerable differences in infection rate and AUDPC values, reflecting variability in the speed and cumulative development of Fusarium wilt. Arka Saurabh exhibited comparatively lower disease development, while highly susceptible germplasm accessions showed rapid disease progression and greater disease accumulation. The identified tolerant and less susceptible germplasm accessions can be utilised as potential sources in tomato improvement programmes for developing Fusarium wilt-resistant cultivars.

Screening of Chickpea Genotypes for Fusarium Wilt ( Fusarium oxysporum ) Resistance Under Field Condition in West Hararghe, Oromia

Fusarium wilt, caused by Fusarium oxysporum f. sp. ciceris, is a major constraint to chickpea production worldwide, resulting in substantial yield reduction and deterioration of crop quality. The effectiveness of host resistance is often challenged by the emergence of new pathogen races, necessitating the continuous identification of resistant germplasm for breeding programs. This study was conducted to identify chickpea genotypes with resistance to Fusarium wilt and to select promising materials for further breeding. A total of 47 chickpea genotypes, along with two standard checks (Geletu and Dimtu), were evaluated under field conditions during the 2022 and 2023 main cropping seasons using an augmented experimental design. Disease incidence was recorded at both seedling and flowering stages, and genotypes were classified according to the ICRISAT disease rating scale. Considerable variation in disease response was observed among the tested genotypes. Two genotypes exhibited resistant reactions, while seventeen were categorized as moderately resistant. Overall, nineteen genotypes demonstrated desirable levels of resistance and were identified as valuable sources of resistance for future chickpea improvement programs. These genotypes can be advanced to subsequent breeding stages for the development of Fusarium wilt-resistant chickpea varieties.

Current status and determinants of tomato Fusarium wilt ( Fusarium oxysporum f. sp. lycopersici ) epidemics under high-tunnel production system in northwest Ethiopia

Background : High-tunnel tomato cultivation technology is vital for year-round production during the rainy season and for enhancing income among smallholder farmers in north-west Ethiopia. However, its productivity and sustainability are adversely affected by Fusarium wilt (FW) disease. This study assessed the current status of FW epidemics, examined associated biophysical factors, and characterized Fusarium oxysporum f. sp. lycopersici (FOL) isolates during the 2024 main cropping season. Methods : A total of 75 high-tunnel technologies were inspected in four major tomato-producing districts within two zones. A logistic regression model was used to associate biophysical factors with disease incidence and severity. Results : All the surveyed high-tunnels were infected with FW, with incidence ranging from 43.6% (Libo Kemkem) to 60.5% (Dera), and severity from 41.4% to 58.3%. Disease incidence and severity were strongly correlated (P < 0.001) with district, age and leakiness of high-tunnels, seed type and source, plant and weed density, crop rotation, and irrigation method. Elevated incidence and severity (>50%) were notably associated with Dera district, gray soils, older and leaky high-tunnels, local and unknown seed varieties, informal seed exchange, high plant and weed density, fruit-setting stage, absence of crop rotation, and contact irrigation method. Pathogen isolation and characterization study identified eight morpho-culturally and pathogenically diverse FOL isolates. Conclusion : FW exhibits extensive distribution across high-tunnel technologies, driven by various biophysical factors and has diverse strains. Therefore, integrated management strategies, including cultural interventions and resistant varieties, are imperative for sustainable high-tunnel tomato production in the study area. Further research on temporal pathogen dynamics and molecular characterization of isolates is also recommended.

Efficacy of Trichoderma bio-priming on tomato (Solanum lycopersicum L.) seedling development and early-stage pathogen control

Prevalence and Incidence of Major Fungal Diseases of Tomato (Solanum Lycopersicum L) In Kano and Kaduna States, Northern Nigeria

Tomato (Solanum lycopersicum L.) is a major cash crop in Northern Nigeria, but fungal diseases are widely cited as a principal cause of the persistent gap between smallholder and research-station yields (Mohammed et al., 2023; Usman & Mohammed, 2023). Standardised, farm-level epidemiological data comparing disease burden between contrasting agroecological zones remain scarce. This study determined the prevalence and incidence of five major tomato fungal diseases across eight Local Government Areas (LGAs) in Kano and Kaduna States and compared disease burden descriptively between the two states. A total of 240 tomato farms (30 per LGA) were monitored biweekly over two consecutive growing seasons using standardised photographic field guides and pathologist-verified identification protocols (inter-rater κ ≥ 0.80). Early blight was the most prevalent disease overall, recorded on 86.7% of farms in Kano State and 79.3% in Kaduna State. Because between-state comparisons necessarily used LGA-level means (n = 4 per state) as the unit of analysis to avoid pseudo-replication across clustered farms, these comparisons are reported as descriptive, ecological-level patterns rather than confirmatory population-level tests: Kano State showed a consistently higher late blight burden (74.3% vs. 61.7% prevalence, 95% CI for the difference [9.7, 15.5]) while Kaduna State showed a consistently higher Fusarium wilt burden (73.3% vs. 57.7% prevalence, 95% CI for the difference [-18.7, -12.6]), patterns consistent with the irrigated-lowland versus cooler continuous-monoculture profiles of the two states. Baseline farmer disease-identification accuracy was only 41.0%, confirming that unaided visual diagnosis is insufficient to guide fungicide decisions (Balogun et al., 2023; Yakubu et al., 2024). These findings provide a standardised between-state epidemiological comparison for two leading tomato-producing states and support state-differentiated disease management guidance rather than uniform national recommendations, though confirmatory farm-level modelling is recommended before the between-state differences are treated as definitive.