Houston

Are you absolutely 100% certain that the round fruits are not from the sour orange rootstock? They look like oranges to me! Although a different rootstock can have some effect on the fruit, it is unlikely to change the shape significantly. My guess is they'll tun orange when ripe.

I am 100% sure that they're lemons. They look more like Meyer lemons to me, which are more round. I grafted 4 or 5 scions and about 3 fruited. All scions came from same tree.

Well, Genoa Lemons cannot change to Meyer Lemons by grafting. Not possible!

I agree citrange2. Doesn't make sense.

It may be age of the fruiting tree. It is well known that the fruit quality and characteristics depends both on the rootstock and the age of the tree.

For example fruits obtained on grapefruit rootstock tend to have thicker peel and white

very interesting. thanks eSilviu. The age of the sour orange rootstock is about 10 years. What you said about the grapefruit rootstock resulting in thicker peel is very helpful because it helps me with my next science project.

Just thought of another possible explanation. Perhaps the scions you took were from a rootstock shoot on the original tree which you hadn't noticed was rootstock. Can you go back to the Genoa Lemon tree and have a careful look whether there is anything originating from below the graft line?

rootstoock is very important to the outcome quality/quantity of fruit

citrange2, the genoa has always been leggy, so I took it off the top. I made sure it wasn't part of the rootstock. My next project is to plant a pomelo seed and after a year or two... graft a ponderosa lemon scion on top. I want to see if I can grow the largest lemons. I know the largest was over 10 pounds. Time to have fun with this stuff.

Oh wow! Lol!

Cory