Genetics of the ergot fungus Claviceps purpurea : I. Proof of a monoecious life cycle and segregation patterns for mycelial morphology and alkaloid production.

The morphological and physiological evaluation of single ascorspore lines (F1) obtained from 4 production strains of Claviceps purpurea and the subsequent production and evaluation of an F2 from two of these strains has shown: 1. The breeding system responsible for the sexual cycle of C. purpurea is characterized by monoecism and self-compatibility. 2. Heterokaryosis is neither required for the completion of the life cycle nor for alkaloid synthesis. 3. The huge variability in both mycelial morphology and alkaloid spectra makes it evident that all production strains are highly heterogeneous. 4. A correlation between morphology and an alkaloid pattern was not found. 5. Alkaloid production is, however, correlated with distinct genotypes. 6. In some cases an increase in the total alkaloid content and in the formation of specific alkaloids was also found, showing that the genetic control of these metabolites may be accessible. Taken together these results open up the way to concerted breeding with Claviceps purpurea with the object of improving alkaloid production.