PBF is a partial dominant trait. _expression_ of trait is also temerature dependent.
Usually it takes 3 or 4 dosages to get good pbf. With 2 dosages , some pbf will show up, depending on environment. It shows more in cooler weather.
Extension of how much pbf shows up on plant base, that is how high it goes, would seem to be an independent trait. As is several other traits, such as redish tone as versus more purple. Some with dotting, some with stippling. Check edges of PBF to see these traits.
I haven't studdied genetics of coloured stems, but expect, from what I've seen, that it is also a partial dominant. But a rarer trait then pbf.
Tennesee Gentleman has good sized flower stalks in my garden now, and some of them are quite black.
Innerst is hybridizer of Tennese Gentleman and of Ominous Stranger, so check his material for black stems. A good number of his plicatas have these same genetics in them.
Yes, I do know that convential thought is that PBF is dominant. Sorry, ain't so. I've done my homework on this very thoroughly. Have recorded over 200 crosses for this trait. And data is very clear. Have hundreds of photos of variation on the theme. Should put all this together for an article, but always more things to study, more data to collect. and time just keeps flowing on.
From: thomas silvers <email@example.com>
Sent: Mon, May 24, 2010 7:49 am
Subject: [iris-photos] Re: HYB: Seedling with better than average PBF
"purple-black foliage, stalks and spathes with a turquoise bloom" I hadn't thought of that particular combination - I'll get to work on that, but somebody else might have to take the baton for the final leg ;0)
In all seriousness though, I agree that turquoise sure can be done. Just look at the strides Don Spoon is making with his SDB's (pictured and discussed in the latest Iris Bulletin). I'm hoping that the faint glimpses of turquoise I'm seeing, will advance at a little faster rate, since I'll be working with diploids. All that I've noticed so far has purely been the result of accident, since I didn't start intentionally crossing with turquoise in mind until just last year.
I think the "purple-black foliage, stalks and spathes" part is going to happen a lot sooner. I've already got highly "outbred" (heterozygous) seedlings that show good _expression_ of the different purple plant traits. Next year, I'll start intercrossing and inbreeding these lines to see what double dosages of some of these genes might do. With the three generations of crosses that I've been working on this project so far, I've yet to intercross two strongly PBF irises, I've mostly been intercrossing strong PBF with seedlings having red-margins derived from Iris suaveolens var. rubromarginata.
Chances are... my first all purple-foliaged iris will also have dark purple flowers because the best seedlings I've got in both the tetraploid and diploid lines just so happen to be dark purples and also happen to pass that color on to many/most of their offspring. But I really like your idea of turquoise! I also really liked the contrast of yellow-orange flower against dark spathes like the picture of 'Captured' that Vicki Craig sent me off-line. Really pretty!
I'm really looking forward to growing an iris with purple-black foliage, stalks and spathes with a turquoise bloom. How long do you think it's gonna take? I'm not getting any younger! If the die hadn't already been cast, I'd probably have tried for that turquoise or blue-green color. I've some growing I didn't toss because the color was present. But they haven't cooperated and I haven't given it a lot of attention because I'd already set myself in other directions. I do think it can be done with enough work.