Somewhere, sometime, someone grew a plant that had a certain characteristic, (blueberry taste and smell in this instance), that made it unique and then kept breeding that plant. A lot of new traits are slight genetic variations that occur naturally in all organisms. I breed snakes and, although they aren't plants, the process is the same basically. That's why the market is flooded with a ton of weird looking snakes. i.e. albinos, dwarfs, etc.

As for the purple bud in your link, that's caused by a pigment caused anthocyanin. Not all pot plants are capable of making that pigment. Even the ones that are, don't always show it because the chlorophyll (green) covers all other pigments up. The best way to get the most purple out of your plants (if they're capable) is to keep the nightime temps below 70F.

Another, NON ADVISABLE, way to get some purple would be to starve the plants of phosphorus during flowering.

It's possible that the cooler temps could be interfering in the intake of phosphorus.

I just read an article in a mag about purple bud so thats why I'm the brain on purple right now.

One last tidbit for you all is that the pigment responsible for yellow, orange, red and brown is called carotenoid.

my brain hurts now so i'm gonna go self medicate myself. :rasta:

Laterz