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Abstract

Rice (Oryza sativa L.) is a major cereal crop and staple food for over half of the global population. The rice root-knot nematode (Meloidogyne graminicola Golden and Birchfeild, 1965) poses a significant threat to rice production across major rice-growing regions, particularly under changing cultivation systems such as aerobic and direct-seeded rice. Effective management of this nematode is challenging due to its short life cycle, broad host range, and the lack of effective nematicides. In the present study, twenty rice genotypes were evaluated under glasshouse conditions to identify sources of resistance against M. graminicola. The resistance reaction was assessed using the Relative Root Gall Index (RRGI) and Relative Reproduction Index (RRI), with TN1 serving as the susceptible check. Results revealed that only one genotype, K 2419 (Land race KARI, Accession No. K:2419), exhibited a resistant response, showing significant reductions in both root galling (RRGI: 0.72) and nematode multiplication (RRI: 0.96), compared to the susceptible check TN1. Two genotypes were categorized as moderately resistant, while the remaining genotypes were either susceptible or highly susceptible. The resistant genotype K 2419 was found to be consistently resistant across all four seasons of Kharif and Rabi in 2023 and 2024 in glasshouse. This resistant genotype may serve as a valuable donor in breeding programs aimed at developing nematode-resistant rice cultivars.