RE: RE: HYB: Getting It Straight For the Simple Minded - RePost

Vicki,

I'm the Steve Neil refers to. I am, more or less, like you when it comes to
iris and other plants (maybe worse).  I see something I like, I buy it, and
then plop it in the ground. If it grows, fine, If it doesn't, something else
takes its place. (See, maybe worse than you <g>.) I do have another hobby,
where I am familiar with the taxonomy, and the genetics, or, at least how
the genetics work. I don't know how long you've been on this list, but,
eventually, you'll see the heavy duty threads on hybridization and genetics,
among other things, if you haven't already. In these threads, there are
assumptions made that others understand the underpinning of iris genetics,
at least to some extent. I just wanted to try to gain that ground for those
of us who do not understand this stuff, so, perhaps, we can follow those
threads a bit better, with a greater understanding.

Now Neil is retired, as I understand it. Perhaps I will be retired sometime
in the future. Mayhap, then, I can put some work into doing a little pollen
dabbing as well, and se what happens. Then, again, by then I may be truly
simple minded <g>.

\\Steve// 

-----Original Message-----
From: owner-iris@hort.net [o*@hort.net] On Behalf Of Vicki
Gatling
Sent: Tuesday, May 10, 2005 8:32 PM
To: iris@hort.net
Subject: Re: [iris] RE: HYB: Getting It Straight For the Simple Minded -
RePost

Gosh, after reading this email, I feel so "simple minded".  As a newcomer to
the iris world, all I know about an iris is if I think it's pretty or not!
And I know how to grow the ones I like.  But I am glad there are others that
DO know  about hybridizing them!  You smart ppl just keep developing new
pretty ones and I'll just keep looking at them!!  Thanks!  Vicki Gatling


----- Original Message ----- 
From: "Neil A Mogensen" <neilm@charter.net>
To: "Iris-talk" <iris@hort.net>
Sent: Tuesday, May 10, 2005 5:42 PM
Subject: [iris] RE: HYB: Getting It Straight For the Simple Minded - RePost


> Steve, you have asked some questions about which I believe a number of
> others may also have a degree of curiosity.  I will make an attempt to
> respond "for the Simple Minded."
>
> There is a difficulty about reducing what is incredibly complex stuff to
its
> essential elements without making hash of what occurs in the conception
and
> birth of new plants from the sexual process.  Plants are not quite as
simple
> as animals, but the matter is actually pretty much the same except for a
few
> matters that make no difference as far as your question is concerned.
>
> Normal "simple" plants and animals have two matched chromosomes in the
> cell's nucleus for each chromosome in their basic set.  These are
"diploid"
> organisms, a word from Greek meaning simply "two-fold."
>
> The pollen and the egg are "haploid," also Greek, meaning "half-fold."
Each
> of those chromosomes is unique, and the "how many" is described as the
> "x=number," even though one often sees the expression misstated as
> "n=number."  I'll use "x" below.
>
> Old diploid bearded irises from Europe, like *I. pallida* or *variegata*
and
> the hybrids between them have an "x" of twelve.  There are twelve unique,
> different chromosomes in the set.
>
> With bearded irises, around 1890 or so a few irises collected in Asia
Minor
> (modern Turkey) and other areas scattered from Greece to Afghanistan and
> Kashmir on the border between Pakistan and India began to drift into
> circulation in England and France, and later in the United States.  These
> clones,
> species, or whatever (some confusion reigns about these identities),
several
> of which are still available, were larger, heavier plants, bigger blooms,
> but almost monotously blue-violet bitones in color .  AMAS is one of those
> collected clones, and is listed by a number of major growers for its
> historical interest.
>
> Many crosses were attempted between these Asiatics and garden varieties of
> bearded irises.  Very few of the crosses were successful, and when they
> were, usually only had one or two seeds.
>
> It turns out that many of these Asiatics have the same "x=12" of the
> European irises, but have a total of forty-eight chromosomes, where the
> older, colorful and hardy European varieties had only twenty-four.  They
> were "tetraploid," again, the same Greek, but with "four" as the first
part
> of the word.
>
> What happened to account for these one or two seeds is that something had
> gone awry during development of the occasional ova (or more rarely, the
> pollen grain) that was involved in these hybrid seedlings, and the result
> was a "tetraploid" hybrid because *all* of the diploid parent's
chromosomes,
> two of each, had gone into the ovum or sperm (pollen grain), and when
> fertilized with the Asiatic, produced colorful, beautiful, big hybrids
that
> were fertile.
>
> All of our "tetraploid" TB's are descended mostly from these hybrids.
>
> In a few cases, natural, wild tetraploids of *I. aphylla,* and *balkana*
> have entered into the mix, and some other diploid species such as the
dwarf
> *suaveolens,* *reichenbachii,* (which also has a tetraploid form, I
> believe), *imbricata* and others have been mixed in also.
>
> You may notice that Jim and Vicki Craig in Oregon have a line of
tetraploid
> Miniature Tall Bearded irises (which are a classification normally diploid
> in their chromosome makeup) that have been bred down in size by the use of
> normal Tall Beardeds with *I. aphylla* in complex pedigrees.
>
> None of this has depended on the chemical "boost" that colchicine has been
> used to double the chromosome counts in JI's and Siberians.  Tetraploid
LAs
> also exist.
>
> Your question about the arils and aril hybrids is a more complex one.  The
> "x" of Regelia (Hexapogon) irises is eleven, and that of the Oncocyclus is
> ten.
>
> Several decades ago various people in California and elsewhere began
trying
> to get hybrids between these aril irises from the Middle East, from Israel
> to Iran and Turkey and the bearded irises.
>
> By an extraordinary streak of luck a hybrid occurred sometime before 1910
> between the diploid Oncocyclus species *iberica* with twenty chromosomes
and
> the collected wild tetraploid Macrantha.  This produced a hybrid with all
> twenty of the chromosomes from the Onco, and the normal half of
twenty-four
> from Macrantha.  Following a rule no longer allowed, the species name and
> Macrantha were combined as IB-MAC, which has pollen that is quite fertile.
> It has forty-four chromosomes, four "x" counts, two each of the ten from
the
> Oncocyclus set, and two sets of the twelve from Macrantha
>
> When these chromosomes pair up to begin the process of pollen or ovum
> formation, the ten Oncocyclus chromosomes pair with the other ten like
> themselves, and the same thing happens with the twelve from the TB
> Macrantha.
>
> This behavior makes the plant behave as if it were a normal diploid with
an
> "x" of twenty-two.  However, that isn't what the hybrid is.  So a new term
> comes in.  This is "Amphidiploid," again using the Greek.  There are other
> amphidiploid hybrid varieties and a few species among other kinds in
irises.
>
> Modern ABs that are neither "+" nor "-" are only slightly more complicated
> than this.  They often involve a mix of chromosomes from the Regelias, the
> Oncocyclus and the various classifications of Beardeds.
>
> That evolution has had the hands of many heroic, extraordinarily patient
> people mixed in.
>
> Your comment, "Arilbred iris are crosses with various bearded iris and
aril
> iris. For the most part, these crosses are fertile" opens a Pandora's Box.
> The truth is, by far the largest majority of the early crosses produced
> hybrids that were as sterile as they could be.  It was only by
extraordinary
> persistance, and according to one source I ran across years ago, helped
> along through the throwing of IB-MAC into the mix, that the jump up to
> "amphidiploid" fertile hybrids occured. This history makes great reading,
> and I highly recommend it.
>
> Curiously, there are other possibilities than "tetraploid," by the way.
>
> If I remember rightly, edible modern potatoes are a product of some
> extraordinary collecting and plant breeding by South American Natives that
> involve at least five different wild species.  They are "Octoploid,"
meaning
> "eight-fold" in their chromosome makeup.
>
> Such things as "triploids" and "penta-" and "hexa-" hybrids of various
kinds
> also occur, including in irises.
>
> In animals, on the other hand, any combination above diploid is usually
> fatal.
>
> Neil Mogensen  z 7  Reg 4  western NC mountains
>
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