Depends on the plant. I've got two GMO plants in my house right now; glow-in-the-dark petunias (https://light.bio/) and purple tomatoes (https://www.norfolkhealthyproduce.com/). The tomatoes breed true (i.e. the seeds have the gene); the petunias do not and must be cloned via propagation.
Roses, fruit trees, etc. are the latter.