You could apply mutagens to your breeding stock, but

a) mutagens in general can be REALLY dangerous to humas, are you going to be able to cause a mutation without exposing yourself to a carcinogen?

b) you are not guaranteed to even get a mutation that is heritable, because the process of RNA repair will ..um.. repair it and

c) if you do happen to get a heritable trait, will it even be noticeable

d) will the mutation be detrimental to the ability of the plant to survive its growing conditions, grow to maturity, and produce viable pollen and seeds and

3) if the other conditions are actually met, the chances of that mutation specifically applying to increased resin production are minutely small.

So in theory, yes, but in practice, read up on your Punnett squares and start practicing backcrossing!