ANDROGENESIS
D
EVELOPMENT
OF
H
APLOIDS
Haploid plants develop from anther culture either directly or indirectly through a callus phase.
Direct androgenesis mimics zygotic embryogenesis; however, neither a suspensor nor an endosperm
is present. At the globular stage of development, most of the embryos are released from the pollen
cell wall (exine). They continue to develop, and after 4 to 8 weeks, the cotyledons unfold and
plantlets emerge from the anthers. Direct androgenesis is primarily found among members of the
tobacco (Solanaceae) and mustard (Cruciferae) families.
During indirect androgenesis, the early cell division pattern is similar to that found in the
zygotic embryogenic and direct androgenic pathways. After the globular stage, irregular and
asynchronous divisions occur and callus is formed. This callus must then undergo organogenesis
for haploid plants to be recovered. The cereals are among the species that undergo indirect
androgenesis.