Apomicts

Apomicts are organisms that reproduce through apomixis, an asexual form of seed formation in which seeds are produced without fertilization or meiosis. In plants, apomixis is also known as agamospermy and results in offspring that are genetic clones of the mother plant.

Mechanisms of apomixis fall into two broad categories. Gametophytic apomixis occurs when an embryo sac forms without meiosis and an unreduced egg cell develops into the embryo without paternal contribution. Diplospory and apospory are two variants of this pathway. Sporophytic apomixis, by contrast, develops the embryo directly from somatic cells of the ovule, bypassing the embryo sac entirely. Endosperm development in apomictic seeds may be autonomous or require fertilization of a polar nucleus in a process known as pseudogamy.

In most apomictic plants, seeds are genetic clones of the mother plant, though occasional admixtures with sexual lineages can occur. Apomixis is common in a number of plant groups, including many members of the Asteraceae, Rosaceae, and Poaceae, and is frequently associated with polyploidy and hybridization. Its presence can facilitate rapid colonization by producing numerous uniform offspring and can help maintain advantageous gene combinations.

From an applied perspective, apomixis offers theoretical advantages for agriculture because it has the potential to fix hybrid vigor and reproduce superior genotypes clonally through seeds. However, practical exploitation of apomixis in crop breeding remains an area of ongoing research.