Transfer of pollen grains from anther of a flower to the stigma of a flower on different plant is called as ______

Xenogamy

The correct answer is Option (3) → Xenogamy

Xenogamy: Transfer of pollen grains from anther to the stigma of a different plant .This is the only type of pollination which during pollination brings genetically different types of pollen grains to the stigma.

Autogamy: Autogamy refers to the transfer of pollen grains from the anther to the stigma of the same flower. It occurs within a single flower, and genetically, it involves the self-pollination of the plant. In autogamy, the pollen grains and stigma of the same flower come into contact, leading to fertilization with genetically identical pollen.

Geitonogamy: Geitonogamy involves the transfer of pollen grains from the anther to the stigma of another flower of the same plant. While functionally it is a form of cross-pollination since it involves a pollinating agent, genetically it is similar to autogamy because the pollen grains come from the same plant. Geitonogamy does not introduce genetically different pollen to the stigma.

Chasmogamous flowers which are similar to flowers of other species with exposed anthers and stigma. Chasmogamy is the type of plant reproduction in which the flowers open up, enabling cross-pollination.