Based on my experience of having moved countries, I can tell you that many types of fruit in this new country(AU) is definitely a lot more sweet than what I am used to. This is not scientific research of course and it could be attributed to many things(soil, environment, fertilizer etc) besides favoring the sweeter lineage but I have noticed that it made me stop eating them.

Now a Granny Smith apple here may be different to the Granny Smith apple I used to eat but this is just to illustrate that I am not comparing two different kinds of apples.