Apomixis

Apomixis is a reproductive strategy in flowering plants in which seeds are produced asexually, yielding offspring genetically identical to the mother plant. It bypasses meiosis and fertilization, and can involve embryo development from an unfertilized egg cell or from an unreduced embryo sac.

Two major classes of apomixis relate to the formation of the embryo sac: diplospory (the embryo sac forms from the megasporocyte without meiosis) and apospory (the embryo sac originates from somatic nucellus tissue). In both cases, the embryo can develop without fertilization (parthenogenesis). The endosperm, if present, may also form without fertilization (autonomous endosperm) or may require pollen (pseudogamy).

Apomixis occurs in a variety of plant families, including some members of the grasses (Poaceae), daisies (Asteraceae), and citrus relatives. It is often found in polyploid lineages and can be facultative (co-occurring with sexual reproduction) or obligate. Apomictic reproduction enables rapid production of uniform progeny and can stabilize advantageous genotypes, which has implications for ecology, evolution, and agriculture.

From a crop-breeding perspective, apomixis has attracted attention as a means to fix heterosis by producing true-breeding seeds from superior hybrids. However, transferring apomixis into crops and achieving reliable, faithful reproduction remains challenging. Current research focuses on understanding the genetic and developmental controls of apomixis and exploring its potential for clonal seed propagation and biodiversity maintenance.