Sure. Sour orange. Makes for the very best tasting oranges in the world. Sadly, it is VERY susceptible to Tristeza, and many commercial orchards were wiped out due to being on sour orange. Some have managed to survive until now, and yes, you will taste a significant difference in these old, "heirloom" oranges. Rootstock does impart a difference in taste, it is well-recorded out there in various scholarly citrus articles.

Patty S.

Thanks for the info! So I guess that was a common root stock for lots of orange varieties as well?

The navel is healthy as far as I can tell, but it's buddy next to it seems to always have some kind of problem. I've always assumed it had Phytophthora, but now I'll should go check out Tristeza symptoms. It does not effect the fruit.
It has random branch die back and strips of dead lesions up one side of the trunk like a vertical ribbon, parts make it's way into branches from time to time. The bark under this area will peel away and expose the wood. So far it's been able to out grow it every year and it hasn't girdled the main trunk so far as well. But I'm sure girdling is what kills the random branches that die off. I think it's had this problem for at least half it's life as I remember it doing this back in the early 1980's. I hope it never spreads to the navel orange as they are like 15' away from each other and touch branch tips.
Not sure what the variety is but could be a Robertson's Navel; it ripens 3-4 weeks before the navel, and the tree is about 20% smaller.
Wow, thanks for listening, I didn't mean to ramble on so much, but I love my citrus trees! I also have in pots, 3 Meyer lemons, 2 Yuzu, a Pixie, Page, and seedless Kishu manderines, Bearss lime, Mexican lime, Kiffer lime, and Valencia orange. My family gets tired of listening to me!