Why do we have different coloured apples?

Question

By the way. I think that the word, "coloured" is a UK word only so that if you live in America, it should be "colored." So don't accuse me of having bad spelling.

Answer 1

It's mostly due to the amount of red pigment in the apples. Like different coloured cats, the natural variation in wild apples has been amped up and standardised into varieties during the apple's long period of  cultivation.

btw, if we are talking about apple colours, I have to share these beauties.

http://www.greenmantlenursery.com/fruit/...

Answer 2

Fruit peel pigments work in several ways. It is a signal the fruit is ripe to eat. Plants time the smell and color to the seed maturity so the fruit will be eaten only once the seed is poised for dispersal by the fruit eater.

Apples contain phenolic substances (anthocyanins and flavonoids) in the peel that are pigmenting but they also offer protection from UV damage. This is why so many fruit 'blush' on the side exposed to the sun.

http://jxb.oxfordjournals.org/cgi/conten...

The pigments also protect the fruit from birds pecking and wounding the skin. The anthocyanins are increased in response to the wound.

http://www.publish.csiro.au/paper/PP9770...

The pigments also reflect UV that birds can see. This makes the fruit very obvious to any creature that can see in the UV spectrum. The riper the fruit the more it shows up against its background foliage.

http://www.rsc.org/publishing/journals/P...

This is why green apples are still found by the fruit eaters. They are visible in a light range we do not see.

Flies that lays eggs only on ripe fruit  find the ripe fruit by comparing it to its background.

http://www.blackwell-synergy.com/doi/abs...