Re: Re: HYB: spots (was another terminology question)
iris@hort.net
  • Subject: Re: Re: HYB: spots (was another terminology question)
  • From: C* C* <i*@aim.com>
  • Date: Wed, 27 Feb 2013 07:01:14 -0500 (EST)
I vaguely something. Unfortunately I don't have time this week to look it up. but from what I think I recall, basically it was that aphylla chromosomes didn't match up well with the TB chromomes, even if same number is set. So that crosses with aphylla X TB were amphidiploid.
We are very lucky with iris species, with so many being able to cross and be fertile. This is possible with many closely related species that are tetraploids, just because of having two sets of chromosomes, you get amphidploid , and thus fertility. But we also have many diploid interspecies crosses that are fertile. This is not the usual situation with diploids, in the plant kingdom. It is precisely because of this that we are able to combine so many genes and get such a wide variety of plants, colours etc.
When I look across so many plant genus, Iris seem to be rater exceptional in number of species that can interbreed and produce fertile offspring. I haven't seen anything even close, in other genus. eg Roses , daylilies, carnations, violets, tomatoes, etc, usually involve no more then about 20 (daylillies) the others are much less. With iris we seem to have at least 100. 

Chuck Chapman

-----Original Message-----
From: Bill Chaney <billchaney@ymail.com>
To: iris <iris@hort.net>
Sent: Tue, Feb 26, 2013 6:25 pm
Subject: Re: [iris] Re: HYB: spots (was another terminology question)
I seem to remember someone once quoting a Bee Warburton article on this issue. Does anyone happen to know if that is true, or better yet have a copy of such 
an article?  I think it was in relation to crosses with I. aphylla
specifically.


________________________________
From: Tom Waters
<irises@telp.com>
To: iris@hort.net
Sent: Tuesday, February 26, 2013 1:41 PM
Subject: Re: [iris] Re: HYB: spots (was another terminology question)

There
have been observations of four pumila chromosomes pairing with four
TB
chromosomes in IBs and (I think) 36-chromosome MDBs. These unbalanced
tetraploids are not completely infertile by any means, and relatively
fertile
ones seem to be becoming more common with time, which I have no
explanation
for. Some used to give a "rule of thumb" that if the bivalents
outnumber the
univalents, some fertility can be expected. If you have the
pairing of four
chromosomes I mentioned, an IB has 12+4=16 bivalents, and
8+4=12 univalents.
We also see partial fertility in the 1/4 aril arilbreds.
I think the
supposition is that unpaired chromosomes do not necessarily
stop the plant
from making gametes, and the unpaired ones just end up in
the gametes
randomly. It's possible to have a viable plant with one of two
extra
chromosomes (or one or two missing ones); these are aneuploids. So
the
fertile gametes from these unbalanced tetraploids are those that
randomly
receive an approximately complete set. The probability of that is
small, but
can be great enough to get some good seeds in some cases.
Tom




Tom
Waters


Telperion Oasis ~ www.telp.com/irises


Cuyamungue, New Mexico,
USA (zone 6)

----------------------------------------
From: "Bill Chaney"
<billchaney@ymail.com>
Sent: Tuesday, February 26, 2013 12:02 PM
To:
"iris@hort.net" <iris@hort.net>
Subject: Re: [iris] Re: HYB: spots (was
another terminology question)

I don't want to distract the discussion that
is ongoing, but I can't
resist
jumping in when Chuck brings up the 12/12/8/8
ploidy because I am trying
to
understand how some of these IBs are so fertile
with TBs and MTBs.
Especially
if the 12/12 side comes from aphylla
background.  Would anyone care to
comment
on that or point me to a good
source of information?

Thanks
Bill
________________________________
From:
Chuck Chapman
To: iris@hort.net
Sent: Tuesday, February 26, 2013 8:06 AM
Subject: Re:
[iris] Re: HYB: spots (was another terminology question)
Amphidiploid is
12/12/8/8  these are SDB

There can't be cross overs between
any chromosome
from 8 set and 12 set, as they never pair up in meiosis.
Crossovers only
occur
in paired chromosomes. No pairs = no crossovers. Like,
never ever. If they
ever did, their would be unbalanced chromosomes, and  it
wouldn't be
viable.
that is  the  meiotic cell would die, or any zygote
formed would die.

IB is
12/12/12/8 So can be pumilla spot, on one of the
chromosomes from the  "8
chromosomes"  set.

RE; Chocolate Truffle.  TB X
pumilla = SDB  No exceptions.
And for kickers, ruffles" a recessive trait that
just isn't present in
pumilla
species. So where are genes for ruffles coming
from?  Hell's Fire is a
reddish
black, with  multiple dosages of Ae (check
pedigree)  Thus  all seedlings
will
be purple in a cross with a yellow. So
are you still believing this
pedigree?
Chuck Chapman

-----Original
Message-----
From: Linda Mann

To: iris
Sent: Tue, Feb 26, 2013 10:41 am
Subject: Re: [iris] Re: HYB: spots (was another terminology question)
Amphidiploid version could.

On 2/26/2013 9:09 AM, Chuck Chapman wrote:

The

pumilla spot is only on the "8 chromosome" set. So can't show up
in TB,
Agree, spots are interesting.

TB e-register from pumila, first generation.
There is another one
registered as a TB, but class is probably a typo - it's
IB height.
Others SDB breeding? fertile IBs? cross overs?

CHOCOLATE TRUFFLE
 (Mark Grumbine, R. 2006) Sdlg. MG04-407-7. TB, 29"
(74 cm), EM     S. light
yellow-brown; F. dark mahogany brown, light
yellow area around beards and
shoulders; beards orange; ruffled. Hells
Fire X I. pumila, yellow

eagerly
waiting to see the '39 checklist (Mike, any more TBs registered
from that era
from pumilas?)

Are there more?  What about the pumila spot work that Blyth
was doing,
trying to bring spot 'up' to TB size? Zing Me.
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