Reproduction which does not involve gametic union is

The correct option is B Apomixis

Apomixis is a mode of asexual reproduction. The development of plants takes place without fusion of gametes. It is a powerful tool which fixes heterosis. The developed seeds are maternal clones. The somatic cell directly forms aposporous initial cells which form embryo and finally develops into the seed. In some cases, the megaspore mother cell directly forms the embryo sac and develops into the seed. It does not involve gametic union so, it is unable to create variation as the recombination of parent character does not takes place. The embryo receives the chromosomes from a single parent plant.

So, the correct answer is option B.