SELF-STERILE AUXOTROPHS AND THEIR RELATION TO HETEROTHALLISM IN SORDARIA FIMICOLA.

Eighty morphological mutants in the homothallic fungus Sordaria fimicola were tested on liquid minimal medium for nutritional requirements. Five had nutritional requirements, one for adenine, three for arginine, and one for lysine. All five were from among the eighty single gene mutants that were also partially or completely self-sterile. Nutritional requirements and centromere-locus intervals provide better criteria than morphological characters for selecting self-sterile mutants at complex loci governing heterothallism.