Combining resistance to the root-knot nematode, Meloidogyne javanica (Treub) Chitwood, and Fusarium wilt in hybrid tomatoes

Abstract

Two tomato hybrids bred at the Hawaiian Experiment Station for resistance to Meloidogyne incognita (Kofoid & Thite) Chitmood proved also to be resistant to M. javanica, which is dominant in the Murray Valley and subtropical areas of Australia. These hybrids also possessed resistance to a range of Australian isolates of the fusarium wilt fungus (Fusarium bulbigenum var. lycopersicli(Brushi) Wollenweber & Reinking). Both these important characters were heritable and could be recombined with agronomic quality in hybrids. Fusarium wilt resistance showed positive potence in the progenies. Root-knot nematode resistance had an irregular pattern of inheritance. The potential of varieties as parents was first gauged from simple crosses. The desirable characters were then concentrated in progenies by a modified backoross followed by selfing and successive selection. Yielding ability has been maintained and suitable agronomic characters have been achieved in the hybrids by the breeding methods used. The work has indicated that suitable crop rotation will be necessary to prevent the selection of nematode strains capable of causing severe infection.