As far as epigenetics go, sure you can methylate some genes in a lab and that will block the expression of that gene. Again, for it to be inheritable it has to happen in the germinal cells and remain that way following meiosis and fertilization. There is no evidence that this can occur naturally via an adaptation to stress or the environment.
Cheers
Actually there is. For 2 generations, following the famine that happened in Ireland, the bodies dug up and studied from grave yards being removed, showed a distinct reduction in size. That is height etc. There are 2 possible causes for this, and the combination of both is most likely:
1 epigenetic effects that reverse after a couple of generations, causing smaller bodies that require less food and
2 niche breeding environments causing the larger members of the population to starve allowing the smaller members to survive on reduced intake. This then allows their genes to be passed on where others aren't.
It could not be the second cause alone, due to the effect being temporary rather than evolutionary, hence epigenetic effects as a result of environmental affects.
However, the thread starter is a noob, feeling around in the dark. We've all been there. He just needs to ask questions rather than make statements hoping for them to be corrected by those who know.
PS trifoliar plants are born of trifoliar plants rather than as the result of the growing conditions of their parents. I believe I'm the authority on that subject.