Neil,
Thank you for responding to my questions,
it explained a lot. I am familiar with the use of colchicines to convert
diploids to tetraploids in daylilies. In as much as I am just starting out and
the SA breeding stock I ordered are all newer varieties I assume they all will
be tets. I did checked out the references you provided, what I am learning is
the Iris traits and inheritance are far more complicated then the daylilies I
am use to working with. I did order a copy of The World of Iris from AIS.
Thanks again
Bob Benbow Camdenton Missouri zone 5
From: SpaceAgeRobin@yahoogroups.com [mailto:SpaceAgeRobin@yahoogroups.com] On Behalf Of Neil A Mogensen
Sent: Thursday, June 02, 2005
12:33 PM
To: Space Age Robin
Subject: [SpaceAgeRobin] Re:HYB:
Questions [Robert Benbow]
First I want to add my belated "Welcome!" to you, Robert, in
your coming
among us on the Space Age Robin.
Your question about the diploid and tetraploid
issue is complex. If you
were to look through some of the on-line catalogs
on Siberian Irises, you
would see the "dip" and "tet"
in the descriptions much like they occur with
the Hems. The "tets" are induced,
just like in Hems, with colchicine. Even
some of the same people were involved--Orville Fay
in particular.
There are a few tet Japanese (JI) and Louisiana
(LA) varieties also, the
JI's induced with colchicine, the LA's with either
colchicine or Oryzalin,
the herbicide. One of the key LA folks,
Kevin Vaughn, just happens also to
work for the USDA, so there is some interesting
stuff available to read if
you are interested. Let me know and I can
forward copies of some articles
about the herbicide in use for chromosome doubling
by Dr. Vaughn. He warns,
however, that the dosage level of the chemical is
NOT the same for different
types of irises, and it is a matter of trial and
error to zero in on what
and how much to use for each different type.
The reason you don't see this in Bearded irises is
that nearly everything at
this point is tetraploid, with a few wonderful
exceptions. We'll go into
that history "briefly" (relative to the
usual product of this writer)
below.
Then, if you were to look through the "Quick
Fix" photos on the Historical
Iris Preservation Society (HIPS) website, you
would see quite a mix of
diploid and tetraploid flowers, as the span of
what is shown covers the
period of transition. The URL for the photos
webside is
http://www.worldiris.com/public_html/Frame_pages/QFix.html
Also, on the HIPS site, is a reprint from the
*Garden Irises* publication, a
book now out of print, put out by the AIS many
years ago. Dr. L. F.
Randolph ("Fitz Randolph") and J. Mitra,
plus some others, went through a
list of cultivars and made counts. You might
find that particularly
interesting to browse through, in combination with
any Historical Iris lists
or the photo site above, as there is significant
overlap in the varieties
noted. The URL for the HIPS reprint of this
chromosome count list is
http://www.worldiris.com/public_html/Counts/Cultivar_Counts.html
You may note that there are occasional triploids
and pentaploids included,
plus a lot of one or two chromosome counts off
from the normal 48 of Eupogon
tetraploids.
A brief history:
Native European "true
beardeds"--Eupogons--are mostly diploid with an x=12,
24 chromosomes in the growing plant. The
principal species in the
ancestries of our modern varieties from this group
are *variegata* and
*pallida*. There are others involved, but in
minor but highly significant
ways. That's a good start right there,
however. Large hybrid swarms
between these varieties exist in the wild, and
several forms were given
species names, but later demoted to cultivars or
"generic" descriptions of
various hybrid types.
Around 1890 Dutch tulip collectors brought back
several specimens of live
irises from the Middle East, from Greece, Turkey,
Palestine, the
Mesopotamian areas and even eastward as far as
Kashmir and Afghanistan.
Most of these were Eupogons, but just happened to
be, for the most part,
tetraploids in the wild.
The nomenclatural identities of these plants is a
mess. Few of them are
extant, and there is reason to believe the same
cv's were given different
species names by various botanists in Europe, and some of the cv's brought
into Europe fell
through the naming process cracks. Among them is an extant
collected tetraploid, AMAS, offered for sale
through a number of iris
catalogs. It is one of the significant
ancestors of our modern varieties.
No species identity is attached to it to the best
of my knowledge. If
anyone knows otherwise, I'd be pleased to hear
from them.
The new imports were larger, taller, but boring in
color--almost all of them
bitoned blue-violets to violet-blue selfs (such as
*trojana*) with varying
climatic requirements. Several of them
thrived in southern England,
parts
of France,
and especially California.
They did not fare well in colder
areas.
French, English, and somewhat later, American
breeders attempted crosses
between the familiar (diploid, although that was
not known until much later)
colorful hybrids of European origin with the new
Asiatics. Occasionally one
or two seeds would show up in a pod, usually in
crosses with the older
European cultivars as pod parents. A few
hybrids occurred also between the
types with the Asiatics as pod parents, although
that is rather rare.
The seeds, tetraploid, were the result of
unreduced gametes of the diploid
parent mating with normal gametes of the
Asiatics. The results were
colorful, wonderful, more heavily substanced,
often vastly improved quality
in general, hybrids.
In our genetic history, there is a fairly short
list of the key parents from
which our modern sorts derive. They include
RICARDII, AMAS, MACATHRA, all
collected forms, and the several key seedlings
from those rare successful
crosses, KASHMIR WHITE, of uncertain origin, but
probably the tet species
white form, *kashmiriana*, crossed with a diploid,
DOMINION, several French
varieties (many of which are in the HIPS list of
photos, as well as in the
chromosome counts reprint) and a number of highly
significant American
hybrids, mostly from California. I won't try to list them,
but looking at
the ancestral pedigree charts of the early Dykes
Medal winners available in
the HIPS photo list as subordinate web pages, is
an education in names. SAN
FRANCISCO is only a second generation product, as
are PURISSIMA (not a
Dykes) and a number of other highly significant
progenitors of our modern
varieties.
A diploid, THAIS, was used on PURISSIMA in the
late thirties, and two seeds
resulted, one of which germinated. It was
named SNOW FLURRY and introduced
in 1939 if I remember correctly, and is in the
ancestry of practically
everything currently marketed. It was
ruffled, and had a texture that was
uniquely beautiful.
If you can lay your hands on (or purchase through
the AIS) a copy of *The
World of Irises* you will find this history in far
greater detail, and
chapters on genetics, pigments, diseases and
almost anything else you could
want to know as well. The varieties pictured
are now regarded as
"historics" as TWOI (The World....) was
published in the late 1970's and
needs updating, a monumental undertaking at best.
Around 1940 the last of the diploids were being
introduced. Nearly all the
others from that time on have been tetraploid
EXCEPT in Table Irises--MTB's.
Nearly all MTB's from all breeders, with the happy
exception of Jim and
Vicki Craig, are delightful little diploids.
The Craigs are putting out tetraploids, the result
of downsizing current
TB's with the tetraploid forms (collected) of the
dwarf species *aphylla*,
occuring from the warmer, dryer grasslands of Poland south to
the Balkan
countries, then eastward into the Ukraine and
even farther eastward, I
belive. Their MTB's, and a few from a
tetraploid *balkana,* also a
collected form, from work begun by Gerald Darby in
England,
Wilma Greenlee
from our upper mid-West and most significantly
(regarding MTB development),
Ben Hager in middle California
(Modesto
area). Some of Hager's hybrids are
in the MTB size range and are included in some
lists.
So that's why you don't see "dip" and
"tet" in most catalogs. The
exceptions may be in MTB lists, and the beardless
noted above.
A lot of other types of iris are in or have
tetraploid form as well, if you
ever branch out into growing them. Most
wildlings, however, are diploid.
That's a lot to absorb--it took me quite a while
when I was first starting,
but I had expert, on the ground, help. Soon
I could spot tetraploids and
diploids visually. They just don't look the
same--and the size of the
anthers is a dead giveaway. There is a
whopping difference in the two
types, and the pollen grains under a low powered
microscope are very visibly
different.
Neil Mogensen z 7 Region 4 of the AIS,
western NC mountains
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