how to tell the difference between white sapote (C. edulis) and yellow sapote (C. tetrameria)?

I purchased some seeds of yellow sapote from TWF a few years back. After seeing Jack's sucess with dwarfing white sapote I wanted to try it myself. I was hoping to graft a very aggresive grower onto the yellow sapote rootstock and see what happens. The only problem, my yellow sapote looks just like my white sapote seedlings. Maybe the slightest of peach fuzz on the underside of the leaf but for the most part it looks just like my white sapotes. How wooly are the leaves supposed to be? Does it come with maturity? Any other traits I can use at this stage to ID it (no flowers or fruit yet)? It would be frustrating to have it turn out to be another whtie sapote.

thanks,
-Ethan

The following thread was started by Ethan-Bakersfield 9/9 on July 02, 2009 at 10:35 pm PST

I have a seedling, and it's got peach fuzz under the leaves. I would argue that's the cue.

Although there are some white sapotes that are crosses, such as suebelle, which also has fuzz under the leaves.

The above followup was added by Axel on July 03, 2009 at 8:21 am PST.

Ethan, all the seedlings I have grown have the "fuzz" when immature. The Suebelle has a slight "fuzz", but the yellows are very fuzzy. Nice to just feel it when walking around. Probable hybrids between the white and yellow sapotes would show differences. The seeds on my yellow are decidedly different from the white sapote in that they are shorted and rounder. Seeds on the white are bigger and more pointed or canoe like (but fat). I'll be happy to send you some seeds from the yellow later this year when they ripen, but I'll need to be reminded.

The above followup was added by Jack, Nipomo on July 03, 2009 at 11:26 am PST.

thank you both for the great info. My leaves are just slightly fuzzy, probably not 'pure' yellow.

You are very generous to offer seeds Jack, I would love them. I'll be sure to remind you, about when do the fruits ripen?

thanks again,
-Ethan

The above followup was added by Ethan-Bakersfield 9/9 on July 03, 2009 at 1:38 pm PST.

Ethan, sometime in the fall. I'm sorry I'm so imprecise, but this year has been very strange. Everything is running late. I'm going to put your name on a white tag on one of the trees so I will remember when the fruit is ripe. You know, if your seedling is a hybrid (whiteXyellow) you might have better success dwarfing a white sapote. Mine are like toys, 12-15 inches tall, little fruits. Maybe a cross rootstock could lead to a 8 ft Pike or Vernon tree with normal sized fruit. Then you would have something!

The above followup was added by Jack, Nipomo on July 03, 2009 at 4:35 pm PST.

thank you again,
if my rootstock is a cross that would make for an interesting experiment too. My original plan was to try grafting a very aggressive grower like McDill, Walton or SC onto the yellow rootstock and see what happens. It would be fun to have a 2', 8', and 20' Santa Cruz sapote tree.

Jack, if there is anything you would like in trade please let me know.

-Ethan

The above followup was added by Ethan-Bakersfield 9/9 on July 04, 2009 at 6:59 am PST.

Thanks Ethan...not now. I have a white tag on the Yellow sapote tree and will, therefore, remember when the fruit is in. This is just payback for the hundreds of other folks who have generously given me stuff over the years. A great group of people!

The above followup was added by Jack, Nipomo on July 04, 2009 at 7:17 am PST.

I wonder,
if you had white sapote rootstock, graft on a piece of yellow sapote scion, then eventually graft on some white sapote again....would that give you same dwarfing?

-Ethan

The above followup was added by Ethan-Bakesfield 9/9 on July 05, 2009 at 8:07 am PST.

I like your thinking! It's a double graft, but they do it with apples. Then again, is the interstem yellow X white or pure yellow? Would the length of the interstem have an effect on the ultimate size of the tree? Lots of experimentation to do here Ethan. A long time-line, but not like playing with Jaboticabas. Take a drive over to the coast and get some yellow sapote wood to try out. It's about 2 hours and COOOL here.

The above followup was added by Jack, Nipomo on July 05, 2009 at 9:31 am PST.

Only 2 hours and cool weather to boot! Jack, I would love to see your place, so long as you are not tired of people walking around awe-struck. Feel free to email me and we can figure out when it is good for you.

thank you again,
-Ethan

The above followup was added by Ethan-Bakersfield 9/9 on July 05, 2009 at 2:10 pm PST.