Q. In some fungi such as _____, the fusion of two haploid cells immediately results in diploid cell while in other group of fungi like _____, an intervening dikaryotic stage occurs, called dikaryophase.

 1984  180 Biological Classification Report Error

Solution:

In Fungi, sexual reproduction occurs by formation and fusion of two gametes with their nuclei. This type of reproduction is absent in the fungi group - Deuteromycetes.
In Sexual reproduction, the there is fusion of the nuclei as well as the cytoplasm. The former is referred to as Karyogamy and later as Plasmogamy. In fungi group, Basidiomycetes and Ascomycetes, the karyogamy is delayed and takes place just before meiosis. In the stage intervening between plasmogamy and karyogamy the cells often contain two nuclei or Dikaryons (n+n) and the phase is known as dikaryophase. The life cycle of the such fungi have three phases.
Fungi group like Phycomycetes, dikaryophase is absent and fusion of the haploid gametes forms diploid cells.