Improving tolerance to Fusarium oxysporum f. sp. melonis in melon using tissue culture and mutation techniques

Fusarium wilt is a vascular disease of the Cucurbitaceae family, especially in muskmelon (Cucumis melo L.), caused by the soil fungus Fusarium oxysporum f. sp. melonis (FOM). This pathogen persists in the soil for extended periods of time, and the only effective control is the use of resistant cultivars. During the last three decades, tissue culture techniques have been utilised in crop improvement to generate changes in the genetic material of plants via in vitro somaclonal variations (by organogenesis or somatic embryogenesis) and induced mutagenesis. More recently, researchers have been using in vitro techniques to investigate the effects of fungal culture filtrates or toxins on susceptible and resistant genotypes of different plant species or cultivars to assess disease resistance. This method is effectively used for cucumber and melon. There are various in vitro culture techniques that can be used for cucumber (Malepszy, 1988). In this chapter, we show a method for mass-selection of melon mutants resistant to Fusarium wilt. In vitro selection of resistant cells, from both irradiated and non- irradiated explants, is performed using culture filtrates of different FOM races. This research could lead to the development of new melon cultivars resistant to Fusarium wilt. (author)