Hybridizing Dahlias

Bessie · 2023-09-14T03:43:02+00:00

Krista to discover if seeds are growing in the seed pod, after there are no remaining anthers on the pod, gently squeeze the pods between your thumb and fing...

SteveM

Bessie Dahlias are now considered tetraploid with 92 chromosomes per cell, not octoploid as once thought

How did they get the "92 chromosomes" number?

Bessie

SteveM how they got "92" is a good question. Also, FYI , the November report of the Dahlia Project is on the ADS website and mentions tetraploid dahlias. But since you asked the question, thinking about it, I asked Gemini AI...😀

The tetraploid version then has four sets of these 23 chromosomes, resulting in 92 chromosomes (4n = 92).

Gemini Prompt: How can a plant that's tetraploid have 92 chromosomes
Public link to full response:
https://g.co/gemini/share/8eabc509c4a9

Teddahlia

I remember from the "old days" they would stain the sample and place it under a microscope and count the chromosomes. Perhaps they could not count in the old days or they were right and the new way to do it is more accurate. However, in my quote they use the word "may" for their conclusion. We will see. Tetraploid is only somewhat better for breeders and does not change much.

SteveM

Teddahlia When a dahlia was believed to be an octoploid I thought the number of chromosomes was stated to be 64. That would make a tetraploid dahlia 32. I don't see any math that will give a dahlia 92 chromosomes.

Ludmila

Teddahlia my understanding of hybrid vigor is that it's mostly an absence of inbreeding depression.

Teddahlia

"my understanding of hybrid vigor is that it's mostly an absence of inbreeding depression."
Inbreeding is very difficult for tetraploid or octoploid organisms. I could be done but it would take many years of breeding.

Ludmila

Teddahlia

Inbreeding is very difficult for tetraploid or octoploid organisms. I could be done but it would take many years of breeding.

Yes, that's a whole point! There is no inbreeding depression, so no hybrid vigor either.

SteveM

Bessie Gemini Prompt: How can a plant that's tetraploid have 92 chromosomes

It is possible for a plant to have 92 chromosomes in a cell but it is not the case with dahlias.(I'm pretty sure).

What does Gemini say with this prompt:
what is the haploid number for dahlias

The chromosome number is more of a curiosity since it has very little to do with the choices we make as breeders. We are more interested in the genes and their alleles.

Teddahlia

A PhD corrected me when I kept saying genes when the proper word for that sentence was allele. They like to split hairs. Genes are what we think of but an allele is word for one of a set of genes than can "fit into the same spot" So, a sentence would go from: " there are many genes that can affect that trait " to "there are many alleles that can affect that trait". Dahlias have lots of genes and lots of alleles. So for a trait there may be 3 or 4 or more alleles for that "spot" and since they are tetraploid,(I wonder about that) there are 4 positions for alleles and all 4 could be different. When they are octoploid(they have not yet said for certain) there are 8 positions but I doubt there are many with as many as 4 different alleles and so whether tetraploid or octoploid it is very complicated. Theoretically. a tetraploid could be made homozygous(all alleles the same) twice as easy as an octoploid. But twice as easy is still nearly impossible.
Boring, boring, boring says Margaret. She says that observing traits and crossing two with that same trait gives you more flowers with that trait. She says that it is so obvious that anyone would know that. One cannot argue with results.

Teddahlia

Taking cuttings of everything good. 2024 best seedlings included. Three taken from the very best one.
Yes, this one.

Juliarugula

Teddahlia I remember a few years ago you commented that you and Margaret had a seedling that you were both super excited about and hoped to release in a few years. (I realize that’s sort of non specific, but you seemed to think it was really something special, so maybe you’ll know what I’m talking about). Is it a variety that has been released now that it’s been a couple of years, or is it still being evaluated. (Or did it get lost or not make the cut?).

I may need to see if I can find the old post…

Edited to add…. I gave up. Just crossing my fingers now!

Teddahlia

Juliarugula That happens every year. The pink one is a close up of Margaret's favorite one from 2024. No full frame pictures of the best first year seedlings as they have to prove they are still good a second year. HH Cheerio and HH Sincerely are "not waterlilies " that I love and Sincerely is released and was sold and Cheerio is being held back to accumulate tubers for next year. It was mis-labeled by me at our trial garden but passed with high score at the other trial garden. It is really nice but Margaret will say not as nice as her waterlilies and two of them are in the trial gardens this year.

Juliarugula

Teddahlia That happens every year.

🤣. I thought that might be the case.

Teddahlia

"Lost Angel" from 2013. Some really nice flowers just do not make tubers that keep.

Teddahlia

I like this older seedling and it may well be related to KA Bo Peep. It is much larger and is a BB sized flower.

Juliarugula

Teddahlia I like this older seedling and it may well be related to KA Bo Peep. It is much larger and is a BB sized flower.

That’s really beautiful. I can see the relation to KA’s Bo Peep, which is one of my favorite KA varieties. I think I may have lost it this year unfortunately. The tubers were really weird and seems like they may not have stored well. Not 100% sure yet. I’m hoping it will be available at the Elkhart Dahlia Society sale in May.

It makes me think of a cross between KA’s Bo Peep and Hollyhill Zarina.

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