In Phalaenopsis, a standard diploid plant (2n) has 38 chromosomes. As Ray mentioned above:
- 3n is normally sterile.
- 4n exists too, which will not easily breed with a 2n.
And, have just seen a notice that at least one 8n has been identified.
If you are selfing, this should not be an issue (unless the plant is a 3n).
In certain other genera, the chromosome count varies from species to species (and sometimes within the species). This significantly limits the seed production (especially in Paphiopedilum).