Some Observations on the Sexual Behavior of the Progeny of Six Isolates of Dictyuchus Monosporus

SUMMARY Single-spore strains from six isolates of Dictyuchus monosporus exhibited the following types of behavior when mated to their respective parental strains and to tester strains of opposite mating reaction to that of the parental strains: (1) heterothallism, in which one of the strains reacted as male and produced antheridia which became applied to oogonia produced by the female-reacting strain; (2) heterothallism, preceded by homothallism in one of the strains in the region of contact between the paired strains, the homothallic strain reacting as male and the opposing strain as female; (3) homo-heterothallism, in which both strains were homothallic in areas adjacent to one another and both were involved in reciprocal cross reactions. With only one exception, there was no sexual reaction between the male isolates and the single-spore strains derived from them. The reactions of the single-spore strains derived from female isolates and mated to their respective parental strains were varied and differed according to the origin of the strains. Variations in sexual behavior also occurred among single-spore strains from some sporangia.