Androgenesis is a form of quasi-sexual reproduction in which a male is the sole source of the nuclear genetic material in the embryo. Two types of androgenesis occur in nature. Under the first type, females produce eggs without a nucleus and the embryo develops from the male gamete following fertilization. The term androgenesis refers to plant regeneration directly from microspore culture under in vitro conditions. As a result of sporophytic divisions, multicellular microspores develop within the anthers. Differentiation of these multicellular units may result in pollen embryos, which then develop into haploid plants.