THE PARASEXUAL CYCLE AND LINKAGE RELATIONSHIPS IN THE STORAGE ROT FUNGUS PENICILLIUM EXPANSUM

Abstract

One hundred and four nutritional, morphological, and acriflavine-resistant mutants were produced in a strain of Penicillium expansum isolated from an infected apple. Nutritional mutants were induced more readily with ultraviolet than with gamma radiation. Heterocaryons were established between strains involving up to eight pairs of markers. Heterozygous diploids were recovered with comparative ease following treatment of the heterocaryons with D-camphor but with great difficulty in untreated heterocaryons. Screening of more than 500 million conidia from three untreated heterocaryons failed to yield a diploid. Analysis of 110 independent segregants from the heterozygous diploid M53/M67 has resolved seven genes into two linkage groups, viz. I: w₃bi₁pyr₁br₃, and II: nic₂ri₁acr₁.