Post‐infection development and histopathology of Meloidogyne arenaria race 1 on Arachis spp.

The reproductive behaviour of the root‐knot nematode Meloidogyne arenaria race 1 was compared on two wild species of Arachis ( A. duranensis and A. stenosperma ) and cultivated peanut ( A. hypogaea cv. IAC‐Tatu‐ST). The three species were considered moderately susceptible, resistant, and susceptible, respectively. Penetration and development of the root‐knot nematode in the resistant species was reduced in comparison with that occurring in susceptible plants. Several cell features, including dark blue cytoplasm and altered organelle structure were observed in the central cylinder of A. stenosperma , indicating a hypersensitive‐like response (HR) of infested host cells. Neither giant cells, nor nematodes developed beyond the second stage, were found on A. stenosperma. Arachis duranensis showed a delay in the development of nematodes in the roots compared to A. hypogaea. The two wild peanut species were chosen to be the contrasting parents of a segregating population for mapping and further investigation of resistance genes.