Integrating grafting and bio-inputs for sustainable management of root knot nematode, Meloidogyne incognita, in tomato cultivation

Nagachandrabose, Seenivasan, Mookiah Shanthi, Sankaran Pagalahalli Shanmugam, Thiyagarajan Elaiyabharathi, Radhakrishnan Sharmila, Kandasamy Devrajan, Ravishankar Manickam, and Ramasamy Srinivasan. "Integrating grafting and bio-inputs for sustainable management of root knot nematode, Meloidogyne incognita, in tomato cultivation." Frontiers in Plant Science 16 (2025): 1623444.

Introduction Root-knot disease in tomato, caused by Meloidogyne incognita, presents a major challenge to global tomato production. This study explored a sustainable management approach by evaluating host-plant resistance through grafting combined with bio-inputs in farmers’ fields with high natural infestations of M. incognita. Methods The commercial F1 hybrid Shivam® tomato was grafted onto bacterial wilt-resistant eggplant rootstocks, EG 203 and TS 03. Two field experiments were conducted with six treatment groups to compare the performance of 'EG 203-tomato' and 'TS 03-tomato' grafts against the non-grafted hybrid tomato, both with and without bio-input applications. The bio-input protocol included soil application of neem cake (250 kg/ha) and soil and seedling drenching at nursery and transplant stages using biocontrol agents (Bacillus subtilis, Trichoderma asperellum, and Purpureocillium lilacinum, each at 5 g/L). Results Results indicated that the 'EG 203-tomato' graft demonstrated strong resistance to M. incognita, while the 'TS 03-tomato' graft remained susceptible, akin to the non-grafted Shivam® hybrid. The EG 203-tomato graft treated with the bio-inputs achieved the highest suppression of M. incognita, with reductions of 76.8–77.7% juvenile populations in the soil, 62.0–66.1% in female populations within roots, 73.6–77.3% in egg masses per female, and 38.1–40.0% in eggs per egg mass. This treatment also resulted in the lowest root gall index, measured at 2.0–2.1. Discussion In both trial locations, 'EG 203-tomato' graft plants enriched with bio-inputs outperformed the non-grafted tomato in growth and yield metrics, achieving greater plant height (54.6–54.7 cm), leaf count (81.3–84.3 per plant), branch count (3.1–3.7) and fruit yield (10.8–11.5 kg/plant). These findings support the recommendation of EG 203-tomato grafts with bio-input management as an effective large-scale strategy for tomato growers combating M. incognita infestations.