In Vitro Response to Fusarium Elicitor and Toxic Substances in Crosses between Resistant and Susceptible Carnation Cultivars

To assess the correlation between in vivo resistance to F. oxysporum f. sp. dianthi and in vitro behaviour, calli from several resistant and susceptible Mediterranean carnation cultivars and F₁ progenies of crosses were tested both for the ability to grow on a medium containing crude culture filtrate of F. oxysporum and to produce phytoalexins following treatment with cell wall components (elicitor) of the same fungus. The results show no significant correlation between in vivo resistance and in vitro tolerance to culture filtrate of the fungus, while there was a good correlation in die case of phytoalexin production. Moreover, the character phytoalexin production behaved as a dominant in the crosses between a resistant and a susceptible cultivar.