Couple of weeks ago I was eating Florida Navel, I cut down the center of one and there was a fully formed, seed of good size. Unfortunately, I cut it half, but I was suprised to find this seed. How can this happen in the Naval variety and what would you wind up with if you planted sowed it?

More than likely an orange, but not necessarily a nucellar clone ?

Finding seeds in Navel Oranges is fairly common. Seeds in Navel Oranges comes up on this forum from time to time. Use the search function and you can read the other posts on this subject if your interested. Planting a seed from a Navel Orange would probably give you another Navel Orange. - Millet (1,081-)

Thanks Millet.

All the navels I've grown have seeds, 5 or 6 per fruit. This is for both washington and red navels. I believe they try to grow the navels in California in massive blocks to minimize seeds.

I really didn't know that, I thought, in general, they were seedless. I also figured the the mutation with the Navel or the sistier fruit had something to do with this.

Florida navels nearly always have at least one seed. Interestingly, while they are technically nucellar, there will usually be a high percentage of the nucellar seedlings that have mutated a bit, so you get "selections" that are not quite identical to the parent. Most Florida navels are of that sort -- 'Summerfield', 'Glen', 'Dream', etc., that are better-adapted to our growing conditions than was the original 'Washington'. So your seed will likely produce a navel orange tree, more than likely identical to its mother, but with the potential for a slight difference.

I heard that seedless citruses are require isolation on plantation. And if your neighbor farmer plant some other citruses near by - your crop of seedless will get some seeds inside from cross pollination. It is a big problem to isolate your plantation in such a small world...