Incompatibility inMicrosporum cookei

Abstract
Seventeen isolates of M. cookei including 2 tester strains of N. cajetani were crossed with each other in all possible combinations on soil-hair medium. Of the 17 isolates, 6 were of — mating type, and 11 of the + mating type. Of the 66 crosses between + and - isolates, only 19 were abundantly fertile, and 31 completely sterile. A high degree of infertile or poorly fertile crosses between + and - isolates showed that there was a number of genetic factors leading to incompatibility in this species.