Swingle, maybe tetraploid.

Very interesting. It looks like Citropsis leaves that are said to be the ancestors of citrus.

I've read that this occurs sometimes with Poncirus, but I've never seen it before. Cool that it happens with its hybrids as well. Is it only the one leaf?
If it were tetraploid I'd expect the leaf blades to be somewhat larger than its peers. One method, if you have a microscope, is to look at the size of the stomata. Tetroploid stomata are significantly larger than those on a diploid.
I wonder if a plant were propagated from that leaf tissue if it would result in trifoliate or pentifoliate dominance? My guess is trifoliate, but it would be fun to think that it might not be. People who breed daylilies find occational flowers with extra petals and have managed to breed lines with higher and higher percentages of flowers having those extra petals.

Last winter Surflan was applied to Swingle seedlings. From about 20 plants, one of them was obviously different. It had darker green and thicker leaves. The shape of the leaf was different, more rounded, and the surface was bumpy, perhaps meaning larger stomata.



The roughness is apparent in the picture

The pentfoliate leaf is from another plant. It is possible it might have been treated with Surflan, but at the time did not look successful. It spent the winter in a semi-protected area outside, and the leaf was just noticed.

I have thought about tissue culture. It would be cool to see if there was some property in that leaf that was maintained.

Very nice HV! I've got plans to do some Surflan work myself, but on raspberries to prep for a wide cross. Haven't gotten to it yet. Did you use the gelatin method?
Just curious, are you building a tet line to use for generating triploids, for larger fruit or just for the joy of seeing what may present itself?

"Did you use the gelatin method?
Just curious, are you building a tet line to use for generating triploids, for larger fruit or just for the joy of seeing what may present itself?''

The gelatin method was new to me this week. It looks a lot easier than saturating a paper towel.
Swingle was used because that was the seed I had. The goal is to make triploids.

Good luck with your breeding attempts

Alan

I've had a few swingle leaves like that. I'll have to get some photo's next time I find one.

Someone could explain what is gelatin method?
I know protocols for doubling the chromosomes, but not this one.

Sylvain, I called it gelatin without looking back at my notes, but the paper I was thinking of actually used agar. Gelatin may work too, though agar sets up at higher temperatures and would probably be easier to work with. I will use agar. In this method you make a dilute solution of oryzalin (active compound in Surflan) and add a thickener, like gelatin or agar to make the solution set up semi solid. A drop of the warm solution is placed on the cotyledons of seedlings when they first break ground and have no true leaves. The reason for the agar is to aid the droplet to stay in place for several days to allow sufficient contact time of the solution with the growing meristem region.

To do this with citrus you'd first remove the coat off the seed and plant shallowly to allow the cotyledons to break from the ground.

http://www.ces.ncsu.edu/fletcher/staff/tranney/polyploid.pdf

Thank you. Very interesting!

Here are two I took off the same plant today.

Swingle crossed Poncirus with Thompson Navel Orange and got one plant that was mostly pentfoliate. Here is the link

http://bulbnrose.x10.mx/Heredity/Swingle/Swingle1911/Swingle1911.html

The picture is to the right.

He also points out HYPOPHYLLS. Several seedlings I have show that pattern.