Re: MED: I. aphylla
- To: Multiple recipients of list <i*@rt66.com>
- Subject: Re: MED: I. aphylla
- From: T* T* L* <t*@rt66.com>
- Date: Fri, 28 Mar 1997 11:05:21 -0700 (MST)
:Tom Tadfor Little wrote:
:>
:> Tetraploid SDBs are a real breakthrough in median breeding. Their '96
:> introduction, ARRIVAL, is the only other tetraploid SDB I know of.
:>
Rick replies:
:
:Please correct me if I am wrong, but aren't most SDB's tetraploid. I
:know that Pumila derivatives are 40 chromosomes and Aphylla derivatives
:are 48 chromosomes but both are tet's.
You're correct, but in this context "tetraploid" refers to fully tetraploid
48-chromosome irises, rather than 40 chromosome amphidiploids. Sorry for
the confusion, but it seems to have become commonplace to talk about the
48-chromosome medians (whether BB, IB, MTB, or SDB) as "tetraploids", even
though both conventional SDBs and IBs also have four sets of chromosomes.
We need an unambiguous term for a tetraploid in which all chromosome sets
are essentially homologous. "Autotetraploid" comes close, but it not
correct because it implies that all the sets are from the same species and
perfectly identical. The TBs (and aphylla-based tetraploids) have 4 sets of
chromosomes which are very compatible but not identical.
Any suggestions?
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Tom Tadfor Little telp@Rt66.com
Iris-L list owner * USDA zone 5/6 * AIS region 23
Santa Fe, New Mexico (USA)
Telperion Productions http://www.rt66.com/~telp/
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