Question

Recurrent apomixis is
a. Parthenogenesis
b. Diploid parthenogenesis
c. Haploid parthenogenesis
d. None of the above

Answer 1

Hint: Apomixis does not involve meiosis and syngamy. In this method of reproduction, gametes are not used. In recurrent apomixis, incomplete meiosis occurs in megagametophyte, so its ploidy level remains the same as the mother plant. Here, both the egg-cell and embryo are diploid. The embryo sac develops from the megaspore mother cell & generally observed to occur in an archesporial cell or nucleus. So, Recurrent apomixis is also called gametophytic agamospermy.

Complete answer:Apomixis does not involve meiosis and syngamy. In agamospermy (seed is retained as an agent of propagation but the embryo is formed by some process in which normal meiosis and syngamy have been eliminated).
Types of agamospermy:
gametophytic agamospermy
 sporophytic or adventive embryony
In gametophytic apomixis, embryo sac develops from the megaspore mother cell by circumvention of meiosis (Diplospory) or directly from a cell in the nucleus (Apospory). In apospory megaspore mother cell is undifferentiated and diploid somatic cell is spore. The embryo is formed by the unfertilized egg (parthenogenesis) or some other cell of the embryo sac. When the embryo develops directly from a diploid egg the process is also called recurrent agamospermy. In this case, the embryo develops parthenogenetically. Since parthenogenesis is occurring in a diploid egg, it is also called diploid parthenogenesis. In Non-recurrent Agamospermy, an embryo develops parthenogenetically from a haploid egg.

So, the correct answer is (B) Diploid parthenogenesis

Note: In recurrent apomixis, due to incomplete meiosis the megagametophyte has the same number of chromosomes as the mother plant. So, both the egg-cell and embryo are diploid. In an archesporial cell or nucellus the embryo sac develops from the megaspore mother cell. This is generally observed to occur. Recurrent apomixis is also called gametophytic agamospermy.
In this method, embryo sac develops from the megaspore mother cell by Diplospory or nucellar cell by Apospory. In apospory megaspore, the mother cell is undifferentiated and diploid somatic cell acts as a spore. The embryo is formed by parthenogenesis or some other cell of the embryo sac. Since the embryo develops parthenogenetically from a diploid egg, it is also called diploid parthenogenesis.