A fascinating site with excellent information of flower colour potential.

While the study was based on the monkeyflower, the genetics can be extrapolated out to other types of plants and for other fields of study in the plant world. It covers not only " the huge variety of flower colors that exist" but extends into what's referred to as "Overdominance" (again, while specifically studied in the monkeyflower, this can be applied to daylilies).

Overdominance ... to quote from one section:
"... overdominance affects the intensity of flower color. If two specific inbred lines — one with light pink petals and one with very pale petals — are crossed, the hybrid offspring are dark pink. Researchers discovered the dark pink monkeyflower is a case of single-gene overdominance. It is dark pink because it has two forms (alleles) of a single gene. It gets one from each parent."

This may, to some extent, explain why ... when two pale purple daylilies are crossed, an intensely purple daylily may result.

The site also addresses why a hybrid cross may do 'better' than either parent (might be more vigorous or produce / yield better). It's as though you have distilled the essence into a concentrated form.

At any rate, I found this article to be a great read, with most of the science in layman's terms.

https://learn.genetics.utah.ed...

Interesting!

Recently on these threads there was posted an old daylily table of crosses, to show if you cross color A with color B, what rates of color progeny you would expect from the kids. It came from a researcher way back when. It was fascinating I think possibly on a thread about 'muddy' daylilies and clearing them up ('clarifying', I think is the term)?
OK, here is the image from Maurice:
https://garden.org/thread/view...

Here is the old thread it is from:
The thread "Crossing daylilies for a certain color" in Daylilies forum

Unfortunately, the links in the threads are old and don't actually lead to the charts done by Dr Carr, but thanks for posting the older thread. It's another interesting read.

On the other hand, the link I posted is not so much about what colour crossed with which other will produce a specific result (whereas Dr Carr's study represented dominant vs recessive traits and results thereof); the article instead addresses more towards intensity of colour and why two pastels (for example) might result in a bloom with a vividly intense colour shown in neither parent.

Yes, sometimes you cross 'x' with 'y' and get 'z' ... and end up scratching your head, wondering how two reds resulted in a yellow... that would be Dr Carr's charts, showing that each red carried a recessive for yellow that, when passed by both parents, presented in an off-spring.

Let's face it: nothing can occur visually (present itself) unless the genetics are in the background of the genetics. It may well be that a true blue is possible ... once you have crossed enough recessives with recessives to eliminate the dominant genes.

But intensity is a different issue. Crossing a pastel purple with another pastel, and ending up with a vivid colour results (from the study on the monkeyflower) from doubling a allele which, when received from both parents, expresses in intensity.

That may explain why when 'Primal Scream' and 'Outrageous' were crossed (Outrageous being a child of Primal Scream) it resulted in 'Screamsicle', which seems to have combined the best of both and intensified even further the vibrant, flaming orange colour. You've apparently taken that allele from Primal Scream and passed it in a double dose to Screamsicle.

I am in no way attempting to explain daylily colour inheritance or rewrite the work / complex studies of highly qualified hybridizers with PhDs in genetics. Simply thought others might find the article interesting, as it applies in plant genetics well beyond the 'simple' scope of daylilies.

Thanks for the acorn.

adknative said: This may, to some extent, explain why ... when two pale purple daylilies are crossed, an intensely purple daylily may result.

It might, but there is a more likely explanation for daylilies based on the research by Arisumi on red flower colour inheritance in daylilies. In daylilies reddish flower colours are typically based on the red-purple pigment cyanidin and purple/lavender flower colours are typically based on the blue-purple pigment delphinidin. Arisumi concluded that red flower colour (versus not red) was inherited dominantly but that the intensity of colour was determined by many genes acting quantitatively (that is by adding or decreasing the amount of pigment in the flower). The same thing will be true for the lavender/purple pigment.

There could be 20, 30, 50 or more different genes in daylilies that affect the intensity of lavender/purple flowers. The genetic differences in those genes in typical daylily cultivars or seedlings would overwhelm any differences possibly caused by an overdominant single gene (if one was even present in the daylily gene pool).

That presupposes that light purple is not a simple result of the genetics for purple in tetraploids. In tetraploids daylilies might be +/+/+/+ purple, +/+/+/- lighter purple, +/+/-/- light purple, +/-/-/- very light purple. In tetraploids inheritance is not simple -- a cross of +--- X +--- (light lavender/purple?) can produce some seedlings that are +++- or even ++++ (deep lavender/deep purple?).

@admmad Thank you for weighing in, Maurice, your sound background in the science is always appreciated. I have been browsing the database and reverse tracking, up to parents / grandparents, etc.

While the descent inheritance is often a surprise and sometimes downright obscure, it's equally fascinating to look at parents and wonder where the off-spring acquired some of their unique traits. I would not suppose anyone would have expected 'Wacky Wednesday' to come from a cross between 'Swallow Tail Kite' x 'Voices Carry' ... or 'Undefinable' to suddenly show up.

To what would you attribute some of the more uncommon characteristics now expressing in recent breeding... the fact that so many more hybridizers now seem to have invested intensive efforts into distinctive breeding lines (thereby pursuing avenues which might, by elimination, be promoting strong recessive traits into dominance) ... or simply that, there have always been 'deviant' lines in daylilies that used to end up on the compost pile and, with more appreciation, are now being pursued by breeders?

...many more hybridizers now seem to have invested intensive efforts into distinctive breeding lines (thereby pursuing avenues which might, by elimination, be promoting strong recessive traits into dominance) ... or simply that, there have always been 'deviant' lines in daylilies that used to end up on the compost pile and, with more appreciation, are now being pursued by breeders?

Both.

There are about 54,000 genes in diploid daylilies. Every seedling will have a few brand new mutations. Nearly all new mutations (about 95%) are "recessive" and will not produce visible changes in the individual plant's characteristics until they are the only versions present in the individual (are homozygous). Over time that can happen purely by chance unless hybridizers always make their crosses between completely unrelated plants. Then what happens is a matter of the hybridizer's choice (hybridizing trends) - the mutant plant may be discarded or used in breeding.