(N/A) Outbreeding devices are mechanisms developed by flowering plants to discourage self-pollination and encourage cross-pollination.
Importance: Continued self-pollination leads to inbreeding depression,which reduces the genetic diversity and fitness of the plant population. Outbreeding devices prevent this by promoting cross-pollination,thereby increasing genetic variation.
Key mechanisms include:
$(i)$ Dichogamy: In some species,pollen release and stigma receptivity are not synchronized. Either the pollen is released before the stigma becomes receptive,or the stigma becomes receptive before the pollen is released (e.g.,$Palms$).
$(ii)$ Herkogamy: The arrangement of anther and stigma at different positions so that the pollen cannot come in contact with the stigma of the same flower (e.g.,$Primula$).
$(iii)$ Self-incompatibility: $A$ genetic mechanism that prevents self-pollen from fertilizing the ovules by inhibiting pollen germination or pollen tube growth in the pistil.