PLANT-PATHOGEN INTERACTIONS OF SUNFLOWER AND MACROPHOMINA-PHASEOLINA IN-VITRO AND IN-VIVO

The relative pathogenicity of isolates of Macrophomina phaseolina was comparable both on sunflower tissue cultures and on mature plants and seedlings. The relative susceptibility of the different sunflower line s in vitro showed a similar pattern for cotyledon callus cultures, but not for immature embryo cultures. Although these protocols appear to be unsuitable for the selection of novel disease resistance, they do o ffer the potential for a rapid, non-destructive screen for resistant m aterial.