Breeding dahlias for petal "substance"

Bessie

Once I felt the firm, thick petals of Dave's Glacier Dahlia, I immediately understood what great petal substance is. There's no doubt I need to add this trait to my hybridizing for cut flowers. I'm looking for your thoughts... Are there any drawbacks to having too much petal substance? How much do you think it contributes to a good cut flower? What dahlias that you've grown have outstanding thick, leathery petals?

SteveM

Bessie If all else were equal I would prefer a cut variety with good substance. I haven't noticed a direct correlation between substance and vase life but good substance can decrease mechanical damage from handling and also decrease botrytis caused by insect feeding.

Teddahlia

"... too much petal substance." I do not believe that "petal substance" is a technical term and it is your words to describe florets that seem to be thicker or heavier than some other varieties. Now where could this "petal substance" come from?

Florets have pigment cells near their surface. Inside the pigment cell is a vacuole full of mostly pigment. It takes up the great majority of the volume of the cell. Now I am guessing. Perhaps if the vacuoles are really full of pigment, the floret would be stiffer and heavier than one without as much pigment. I have seen many white dahlia seedlings with very poor color even to the point that petals look a bit transparent. I have seen florets on a sported flower have a different shape(form) than the unsported version. That would indicate that the amount of pigment in the cells affects form somewhat. As Steve, said above, having more pigment may not make much difference in flower longevity but may help prevent bruising.

Bessie

Teddahlia , thanks for your thoughts. Which Hollyhill Dahlias(or other varieties) do you think have exceptional petal substance?

You got me researching the term "petal substance".
I just took the term as common place, but I think it's mostly used to describe roses. I found this info below fascinating.
From Website: https://www.rose.org/single-post/2018/06/11/rose-classifications

Another criterion for selecting roses is referred to as “substance of the petals.” This quality is extremely important in warm climates where temperatures may soar into the 90° Fahrenheit range. Essentially, substance depends on the amount of starch in the petals capable of holding moisture. The more starch, the better the variety can sustain exposure to high temperatures. Otherwise, moisture is lost, and the blooms begin to droop.

Teddahlia

The ADS uses the word "substance" much more generically referring to all flower parts:
Substance desirable:
Springiness and toughness of the flower parts . Firm, crisp, stiff, thick. Uniform back and face.

Undesirable: Ray florets soft , lack springiness, droopy. Not Turgid. Ray florets missing, shriveled, thin, brown, dirty, misshapen. Overly mature , lack of substance affects symmetry of color.

No where is starch mentioned. I believe vacuoles full of pigment are a big factor.