There is a blood orange since 600 years .. and all others in same area, who are younger have nothing to do with it ...

Well, I cannot follow your logic ...

Besides I know much more about blood oranges than you ever will ...

Point.

Very good article about blood oranges:

http://www.califcitrusspecialties.com/docs/Karp%20blood%20oranges%20Fruit%20Gardener%202007.pdf


according to this article, blood oranges come originaly from China and Moro and Tarocco are mutations of Sanguinello, so I think, they can not be called "half-blood" or somethig like this.

Mutations happen all the time, and surely had influences in the fruits of todays, but nevertheless they are the result of a breeding and crossing with other, blonde oranges.

Maybe you heard before the Sanguinello being called a "full blood orange"
I see that often, even in US articles and nurseries ...

Pink or red coloration of citrus pulp depends of one set of genes, which controls the level of anthocyanins, so I think, you can not obtain deeper red coloration (Moro) by crossing Sanguinello with blond orange. For example: as far as I know, deeper coloration of grapefruits was obtain only by mutation - from spontaneous mutation - like some pink varieties, - to forced mutation of this set of genes with radiaton (buds or seeds) to obtain red pulp varieties- like Star Ruby etc.
But, it is only my opinion.

That is what most think .. but all oranges have the genes.

Actually there are 2 genes who produce blood oranges, both must be there to produce the blood colour and the colder it is the more intensively.

So an orange with a recent blood gene can be well crossed and give even more coloration and even not both genes can passed on to next generation.

Radoslav, thank you for that very interesting article. It is a "must read".
This is real information.

Very informative indeed, thanks!