Question

If a fungal thallus has both male and female reproductive structure, it will be called
(a) Heterothallic
(b) Homothallic
(c) Dioecious
(d) Monoecious

Answer 1

Hint: It is the condition in which Zygospore formation takes place only when mycelia arising from asexual spores of two genetically different mating types, are allowed to interact. It offers the potential of increasing genetic diversity through meiosis.

Complete answer:
If a fungal thallus comprises both male and female reproductive structures, at that point it is called Homothallic and if the thallus consists of only one sex within it then it is called Heterothallic.

Additional Information: The term Heterothallism was first utilized by an American geneticist A.F. Blakeslee in 1904 when he saw that zygospores could develop in some spp. only when two mycelia of various strains were permitted to interact with one other.
Blakeslee mentioned these observations as a result of his studies on zygospore formation in Mucorales. He found that in some certain species of Rhizopus, zygospores were formed freely while in others like R. nigricans zygospores were formed rarely.
The heterothallism might be of two types: Morphological heterothallism and Physiological heterothallism. During Morphological heterothallism, it might be defined as the condition when morphologically different male and female sex organs are produced in two closely associated mycelia. During physiological heterothallism, the interacting thalli vary in mating type or not compatible, irrespective of the presence or not present the sex organs or gametes.
So the correct answer is ‘Homothallic’.

Note: The zygospores upon germination produced germ sporangia which contains spores of only one strain in heterothallic species of Mucor mucedo. The heterothallism promotes out-breeding and that’s why it subserves the same end as the sexual process, which it renders most efficiently. Hetrothallism is not the same as sex, it is refinement superimposed upon it.