Cultivar Screening and Pathogenicity Assessment of Root-Knot Nematode (Meloidogyne incognita) on Tuberose (Polianthes tuberosa L.)

Background: The root-knot nematode Meloidogyne incognita can impair tuberose growth, while the comparative response of available cultivars under the experimental conditions of Odisha requires assessment. Aims: The present investigation was undertaken to study the pathogenicity of root-knot nematode (Meloidogyne incognita) on tuberose under Odisha conditions and to screen different tuberose cultivars against this nematode for resistance. Study Design: Completely Randomised Design (CRD) Place and Duration of Study: Department of Nematology, College of Agriculture, OUAT, Chiplima, Sambalpur, Odisha, between August 2025 and June 2026. Methodology: The pathogenicity of M. incognita was studied on the tuberose variety 'Calcutta Double' by inoculating second-stage juveniles (J₂) at five inoculum levels, viz., 0, 10, 100, 1,000 and 10,000 J₂ kg-1 of soil, replicated five times in a Completely Randomised Design (CRD). Observations on plant growth and nematode parameters were recorded 45 days after nematode inoculation. Subsequently, 15 tuberose cultivars were screened against M. incognita with three replications under pot culture conditions to assess their relative resistance or susceptibility. Results: The pathogenicity study revealed a pathogenic threshold level of 1,000 J₂/kg of soil, at which significant reductions were observed in plant height, number of leaves, leaf area, root length, and fresh and dry weights of shoot and root compared with the uninoculated control, while the number of galls, number of egg masses and soil nematode population increased significantly with increasing inoculum levels. In the varietal screening, out of 15 tuberose cultivars, only one variety (Phule Rajani) showed a resistant reaction, three varieties (Hyderabad Single, Bidhan Pearl, and Pratap Rajani) showed moderately resistant reactions, three varieties (Arka Kriti, Bidhan Jyoti, and Sikkim Selection) showed susceptible reactions, and the remaining eight varieties showed highly susceptible reactions to M. incognita. Conclusion: The present investigation indicated that M. incognita is pathogenic to tuberose, with an inoculum threshold of 1,000 J₂/kg of soil causing significant damage under Odisha conditions. Among the cultivars screened, Phule Rajani exhibited a resistant reaction, while three moderately resistant cultivars were also identified. These cultivars may be recommended for cultivation in nematode-infested fields and utilized in resistance breeding programmes as components of sustainable nematode management in tuberose under Odisha conditions.