Answer:
Parental ditype (PD):
Parental ditype may be defined as the teterad type of the ascus that contains two different genotypes. These genotypes are both of the parental type. These are non recombinant ascospores.
Non-parental ditype (NPD):
Non-parental ditype may be defined as the ascus spores that do not resemble with the parent genotype. These tetrad type are the recombinant type of the ascus.
Tetratype:
Tetratype are the spores that contains the four different genotypes. The two genotypes are the parental type and two are recombinant type. The tetratype indicates the single cross overs.