The relative infection potential of Meloidogyne incognita and M. graminicola in the basmati rice cultivar PB1121

Root-knot nematodes, Meloidogyne spp., are considered one of the major biotic constraints for global rice production. Although the role of Meloidogyne graminicola in root-knot disease progression is well investigated, negligible research has been performed to understand the damaging potential of M. incognita in rice. In this study, the comparative infection biology of M. incognita and M. graminicola was investigated in the basmati rice cultivar PB1121 growing in Pluronic gel medium and soil. Intriguingly, M. incognita laid eggs outside the galled root, whereas M. graminicola egg masses were deposited inside the galled root. This differential egg-laying pattern can be correlated with their specific adaptations in irrigated and upland rice production systems. Although M. incognita induced a greater number of galls than M. graminicola, M. graminicola gall sizes were comparatively larger than those of M. incognita. The greater reproductive success of M. graminicola than M. incognita did not cause any difference in their yield reduction potential in PB1121. PB1121 was equally vulnerable to M. incognita and M. graminicola in terms of reduction in plant height, tiller numbers per plant and grain yield per plant. Our research suggests that M. incognita also causes economic damage to rice, and nematode management tactics must consider the damaging potential of both nematode species.