Mi Introgression Lines as Tools for the Genetic Analysis of Bacterial Wilt Resistance in Tomato

Abstract

Ralstonia solanacearum limits the development and production of solanaceous crops in tropical and subtropical regions of the world. As a soilborne pathogen, the bacterium is codistributed with polyspecific nematodes, often resulting in synergistic effects on wilt symptoms, especially in potato and tomato (Haider et al. 1987; Napiere and Quimio 1980). It is widely reported that nematode activity on roots generates additional wounds that facilitate bacterial entry into the host plant. Generally, this was assumed to account for the synergistic effect (Hayward 1991). However, it has been suggested that nematode wounds cannot entirely explain the R. solanacearum-root knot nematode synergy (Cadet et al. 1989). Recently, we reported that galling caused by root-knot nematode Meloidogyne spp was the primary synergistic determinant explaining failure of bacterial wilt (BW) resistance in tomato (Deberdt et al. 1996).