Genetic control of photomorphogenesis. Isolation of nonfilamentous mutants after gamma irradiation of Pteridium aquilinum spores

Photomorphogenetic mutants of Pteridium aquilinum gametophytes have been isolated after exposure to gamma-rays. The procedure involved screening large numbers of treated spores for their ability to form macroscopically visible prothalli when cultured in the absence of blue light (normally required for prothallial growth). Two hundred and eighty presumptive nonfilamentous mutants were isolated and thirty-nine actively growing strains were tested for expression of the mutant phenotype. The 20 stable mutants thus obtained will provide material for further genetic characterization of the photomorphogenetic process in fern gametophytes.