Which of the following strategies is the only type of pollination that can bring genetically different types of pollen grains on the stigma?
Xenogamy is cross-pollination. In this case transfer of pollen grains from anther to the stigma of a different plant takes place.
Geitonogamy involves the same plant. It is genetically self-pollination.
Autogamy is self-pollination.
Cleistogamy is also autogamy.