SPEC: I. germanica
- Subject: SPEC: I. germanica
- From: S* M* <7*@compuserve.com>
- Date: Tue, 9 Feb 1999 01:50:45 -0500
- Content-Disposition: inline
From: Sharon McAllister <73372.1745@compuserve.com>
Anner Whitehead wrote:
> Fascinatink! Might you tell us more, please?
This is a BIG subject -- sure hope you don't come to regret giving me the
opening!
Bill Shear wrote:
> According to Mathew and the BIS species book, "germanica" is a cluster
of
> "near-species," many of which may have arisen by hybridization. The
> picture is very muddled by the early involvement of man and repeated
> escapes from cultivation of hybrid forms. The bottom line is that no one
> really knows what "I. germanica" is.
Quite true. For my purposes, I lumped all "I. germanica" that I
encountered in published pedigrees under that name. There's no way of
knowing how many different clones were involved or even that all of them
were truly I. germanica.
Mike Lowe wrote:
> Wow! Impressive. Discounting Kochii, Black Prince, Amas, Ricardi,
cyprania,
> mesopotomica, trojana, etc., etc., I have only turned up one instance
out
> of 6000+ TB and 'short TB' pedigrees where I. germanica (44) was fairly
> unarguably used in a cross that comes all the way down to modern talls.
And
> the link to modern progeny is sullied by a question mark on a lineal
> descendent.
> Tell me more!!!
My database is not nearly as extensive as yours -- I did most of this
research in the days before PCs and have keyed in only three categories of
data:
1. The ones I've at least planned to use in my own breeding program,
traced back to unknowns and species.
2. The breakthrough breeders I've identified -- fertile tetraploids from
wide crosses like diploid & tetraploid or triploid & tetraploid.
3. The original tetraploids, used with those in the second group to
produce our modern talls.
In the second two groups, my interest was not in their descendants but in
the mechanism by which the breakthrough breeders had been produced. The
types of crosses involved in the TB tetraploid conversion parallel the ones
being made with arilbreds when I got serious about hybridizing. It's all
there: unreduced gametes from the diploid parents; the use of triploids;
true amphidiploids; crosses between incompletely homologous tetraploids....
The lessons learned during the tetraploid conversion of the TBs had many
parallels among the arilbreds -- and anyone now wanting to breed back to a
higher percentage of "northern" genes in the talls would do well do study
recent advances in the arilbreds.
To get back to Mike's question, the breakthrough breeder I identified as
the conduit of I. germanica genes into the modern pool was PIONEER [Bliss,
1924]. Simonet counted it as a 47 chromosome tetraploid, and I. germanica
was reportedly its greatgrandparent.
Enuf? Or do we really want to go deeper into this?
Sharon McAllister
73372.1745@compuserve.com
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