Triploid block is a phenomenon describing the formation of nonviable
progeny after
hybridization of
flowering plant
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...
s that differ in
ploidy. The barrier is established in the
endosperm
The endosperm is a tissue produced inside the seeds of most of the flowering plants following double fertilization. It is triploid (meaning three chromosome sets per nucleus) in most species, which may be auxin-driven. It surrounds the Embryo#Pla ...
, a nutritive tissue supporting
embryo growth.
This phenomenon usually happens when
autopolyploidy occurs in
diploid plants. Triploid blocks lead to
reproductive isolation. The triploid block effects have been explained as possibly due to
genomic imprinting in the endosperm.
[ Triploid block can be partially overcome by chemical treatment with 5-Azacytidine.]
References
Botany
Evolution
{{botany-stub