Apomixis is a special method of plant reproduction. In this method, the angiosperm plant reproduces without involving steps of usual sexual reproduction i.e. meiosis and fertilization. It can be sporophytic or gametophytic and non-recurrent or recurrent.
According to Hein’s Winkler (1908), the substitution of usual sexual reproduction by a form of reproduction which does not involve meiosis and syngamy is called apomixis.
According to some embryologists, vegetative propagation and agamospermy are also included under the category of apomixis.
According to valid definition apomixis is generally of two types:
1. Sporophytic apomixis: This is also called adventive embryonic. In this apomixis, the embryo is formed from nucellus or integument or any diploid cell of the ovule. There is no meiosis and fertilization.
2. Gametophytic apomixis: In this apomixis, an embryo develops from any cell of embryo-sac. It is of two types:
- When an embryo develops from the unfertilized egg then this process is known as parthenogenesis.
- When an embryo develops from any other haploid cell of embryo sacs such as accessory cells or synergids, then this process is called as apogamy
