Forgive me if this has been answered before, but when a triploid selfs, what ploidy do you get in it’s offspring?
Details in next newsletter. Diploid, triploid, tetraploid, depending on whether it is a 7 or 14 chromosome complement in the pollen and/or the egg. I think the relative yield is skewed by specific parents. Overall, maternal fertility will likely be rather low. Pollen is so abundant that one gets through fairly often. Eggs are few 10-50 per hip. So New Dawn gives only a few seeds per 10 pollinations with tetraploid pollen. Seems same with Rianbow KO (triploid) pollen.
Thanks. I’m specifically talking about Lynnie.
I wish I could tell you, Judith. What I can say for certain is, she seems to work with everything I’ve ever shown her. She’s really made some nice results with Pretty Lady in last year’s seedlings!
Can I ask this question in relation to this thread, “is ploidy testing” does it cost much ?
I think this thread went in the wrong direction. My question was if a triploid (like Lynnie) is SELFED, can one predict the offspring ploidy?
There is evidence that diploid (2x) pollen has a competitive advantage over haploid (1x). Therefore, it stands to reason that you’d have more triploids and tetraploids than you’d expect, relative to diploids.
It should vary for a number of reasons. Like Joe said, there is evidence that 2x pollen may have a competitive advantage over 1x pollen. Leen Leus tended to have more 4x offspring than I did generally in 4x x 3x crosses. I suggested in my paper that it could be due in part to pollen competition and how heavily one applies pollen. If you apply pollen heavily perhaps more 2x grains will outcompete the others and participate in fertilization. If one pollinates more lightly, what participates in fertilization will more closely represent the gametic range. Temperature and other climatic conditions can impact meiosis and can reasonably also lead to variation in percent of viable gametes and their ploidy as well.
Generally I have found that when intermating triploids it is relatively uncommon to find many diploids.
That’s a great question about cost for ploidy testing. The answer is not very expensive if you are using traditional cytology. After you have access to a microscope, the cost is minimal for a little acetocarmine or acetoorcein stain, acid, some vials to store roots and tools to move and cut tips, and slides. The critical part is that you have patience and enough interest to learn how to do it and average to good eyesight.
Besides traditional cytology, there is something called flow cytometry which looks at the relative DNA content of the nuclei of cells as they pass by a laser. It can be streamlined to go smoothly and you can get a lot of samples done somewhat quickly, but it is expensive. It is also an indirect method that can sometimes lead to some errors. Counting chromosomes directly is my preference.
At one time I had planned on separating the pollen from triploid roses by using ordinary gasoline automobile filters (they appear to have the correct pore size). I never got around to trying it.
Thank you! That was what I was looking for! Much appreciated.
The hips of Lynnie I got from Kim a couple of years ago were THE best germinating seeds I’ve ever had. I think nearly every single seed germinated and grew on healthily. I still have at least a dozen seedlings from it. And I also remember that quite a few of the ones that didn’t germinate the first year did the second year. I’m planning on using some of my seedlings this year in my crosses.
That’s funny, Sharon! I’ve been telling everyone, Lynnie is a ‘ho’! Like a teenage rabbit, she’s always on “the hunt” for a mate! LOL!