I noticed in the database that this daylily is listed as a diploid and tetraploid. It is beautiful regardless but can a daylily be both? Can a diploid and tetraploid be crossed? Can you tell which is which by looking at the roots?

It's a tet. A plant can be both, in theory if someone converted the plant. I don't believe this is the case with HOLY GUACAMOLE.

No, you cannot cross a dip to a tet or a tet to a dip and The only way I know to check is by looking at the pollen.

I'm sure that it being listed as both in the database is a oversight. It is a tetraploid and no you cannot tell which is which by its roots. Actually you really can't tell which is which just by looking at any of it physical characteristics. If anything sets them apart, IMHO, is the blooms and that's just the toothy ones and the chicken fat ruffled ones. I don't think there are any dips with teeth or the really ruffled edges. But the most sure way is to look at the pollen.

I had someone ask me in my garden if you could tell a dip from a tet by its foliage (they were telling people that is how you could tell them apart) so I took them to 2 of my beds that are side by side and ask them if they could tell which plants were dips and which were tets and they could not tell me which was which. One bed was nothing but dips and the bed across from it was nothing but tets.


You asked "Can a diploid and tetraploid be crossed?"
Yes and no. You can cross a dip onto a tet and it may make a seed pod but it will eventually abort. If you have a dip that may have been treated to try and convert it to a tet ( but didn't succeed) it may still have a little bit of tet in it (making it a chimera???) and actually take on another tet; I have several seedlings that have a tet pod parent and a dip pollen parents but I know the dip was one that had been treated to try and convert but it was not fully converted or reverted back. It was an accident that this happen the first time as Kim had accidently planted a tet in her dip section and kept putting dip pollen on it and we had it actually take so then I started putting the pollen on a very fertile tet I have to see if I could get it to take and I have about 6 seedlings out of that.

How can you tell by the pollen? Any pictures to show the difference, please? I have some NOIDs that I would like to see if I can tell the ploidy. Thanks!

Thanks Michele. Can you tell the difference by looking at the pollen with your own eyes or do you need a microscope? I have some NOIDs also and I do not know what they are. I was looking up Holy Guacamole because I have it ordered for this coming Spring and I plan on trying my hand at a little hybridizing.

you have to have a microscope to tell which is which

I am posting 2 photos from Bill Waldrop's (thanks Bill ) blog that shows the size of the pollen. He says "Tetraploid pollen usually measures about a 13 or larger, whereas diploid pollen often measures about an 8 to 10, on my scale of measurement"

Really the only way to tell without a microscope is to take pollen from a known dip and a known tet and pollinate the NOID with both and mark the blooms with a tag, colored paperclip, etc, so you will know which one had dip and which one had tet pollen dabbed. I would do this several times with each pollen and then whichever one makes it to the end and has viable seeds is the correct ploidy.

To add to what Michele has already said. If neither dip nor tet pollen cause a pod to set, the plant is either difficult to set pod or it is pod sterile.
In regards to pollen, check out this unusual plant. http://www.bluegrassgardens.ne...

That's interesting Mike.

Holy Guacamole is a tet. I have set pods on it with tet pollen. It is registered as a tet.

Dot

A diploid that has been treated to try to convert it to tet is usually a chimera. The treatment rarely (although sometimes) manages to treat all the necessary parts to make it a complete tetraploid.

If you take a diploid cultivar, say Siloam June Bug (SJB) and treat it to convert it to tetraploid and the conversion works then the tetraploid SJB will have pollen that is about 30% larger in length and width than the diploid (SJB) version's pollen. That is because doubling the number of chromosomes tends to double the volume of the plant's cells and a cell or pollen has about double the volume when its length, width and height are all increased by about 30%.

But different diploid cultivars have different size pollen and different tetraploid cultivars have different size pollen and triploids have a wide range of pollen sizes that falls in between. It is quite likely that there are diploid cultivars with pollen that is larger than some tetraploid cultivars (and/or vice versa).

I don't think anyone has examined diploid pollen from a range of cultivars, small flowered, large flowered, spideries, etc., nor has that been done for a range of tetraploid cultivars.

One can also look at the size of guard cells in the leaves but the same qualifier holds for them as for pollen - some diploid cultivars may have guard cells larger than some tetraploid cultivars.

Bottom line, although pollen size examined under a microscope and measured can give a reasonable idea of whether a plant is a diploid or a tetraploid it is not necessarily a certainty. The only certainty is to have a chromosome count done of the root tips (but that does not necessarily work for attempted diploid to tetraploid conversions - which would require chromosome counts of the pollen).

There are some very rare conditions when a true diploid (pollen) crossed on a tetraploid (pod) may produce a viable seed. The seedling could be a triploid or very rarely a tetraploid. The opposite cross of a diploid pod with tetraploid pollen may also very rarely work to produce a viable triploid seed. Those rare conditions would typically require hundreds of pollinations to get any seeds in some specific crosses and would always fail in other specific crosses.

There are also a few fertile triploid cultivars.

The guard cells look like thousands of eyes, at
least to me. Incredible how plant parts look
under magnification. I think it is amazing.

Sorry, I don't have any of my own photos to
show of guard cells.

Thanks everyone, for the information. It is all very interesting. Out of curiosity, I guess I will be trying some crosses next year just to see if some of my NOIDs set seed.

All really good information and very interesting. I knew that some diploids had been converted. I did check the AHS database for Holy Guacamole and it is listed as a Tetraploid there. Now another question comes to mind. When you register a daylily how do they determine whether it is a diploid or tetraploid when the parents are unknown?

I put in a proposal, which has been accepted, to have the ATP info changed to be just tetraploid.

tgarden711 said: Now another question comes to mind. When you register a daylily how do they determine whether it is a diploid or tetraploid when the parents are unknown?

If it is a true unknown then they would either have to check the pollen or pollinate it with the tet and dip pollen and see which one sets. A lot of times when a daylily is listed with unknown parents it's not really an unknown as far as ploidy. It could have been a seedling that got the tag lost and they are unsure of the cross or a seed pod they forgot to mark when harvesting or tags got mixed up with another close by. I only work with tets so if I had an unknown parentage then I know it's a tet. My friend only does dips so any of her unknowns would be dips. And we keep them in separate beds so there is no way of getting them mixed up and the seedlings are separate as well.

HG should be a nice one to use Theresa!