Re: Fwd: HYB:Interploids and Polyploids
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- Subject: Re: Fwd: HYB:Interploids and Polyploids
- From: "Walter A. Moores" <wam2@Ra.MsState.Edu>
- Date: Wed, 1 Oct 1997 14:23:12 -0600 (MDT)
On Mon, 29 Sep 1997, Sharon McAllister wrote:
> Walter Moores wrote:
> > In LA breeding Mertzweiller mentions the above. Marie Caillet has
> > just sent me CREOLE RHAPSODY (Mertzweiller '98) and it is described by=
> > Marie as being an interploid.
> > Sharon, can you tackle these two terms and simplify them?
> Ploidy is just the number of sets of chromosomes. =
> It tells us nothing about the number of individual
> chromosomes or their types -- just how many sets =
> there are.
> A diploid has two sets.
> A polyploid has more than two sets. That includes
> triploids, tetraploids, pentaploids, etc.
> I haven't encountered the term "interploid" before.
> Intuitively, I'd say the product of a cross between
> parents of different ploidy. It would aptly describe
> the product of such a cross when the true ploidy
> can only be determined by extensive test crosses
> and chromosome counts.
> But that's just an educated guess. The real
> question is what Marie means by "interploid". =
> Sharon McAllister
On page 39 of the SPECIAL PUBLICATION OF THE SOCIETY FOR LOUISIANA
IRISES 1995, Mertzweiller says:
Availability of tetraploid Louisiana irises may open
hybridizing opportunities which have not been available in
the past. What is considered a new hybrid, I. virginica X
tetraploid Louisiana (BAYOU ROUGE), was produced by Mr.
Ken Durio. This is not only an interploidy hybrid (2n
X 4n) but also an inter-series hybrid in the Apogon
(beardless). I. virginica is diploid, 70-72 chromosomes
and a member of series Laevigatae. Louisiana irises
represent the series Hexagone and are mainly diploid,
42-44 chromosomes, with the new tetraploids considered to
have 84-88 chromosomes. A factor favoring hybridization at the
the interploidy level may be related to closer numerical
similarity in the chromosome numbers. This may be mere
speculation and many other factors are likely to be involved.
So, it seems that interploidy relates to inter-species (series)
Later in the article, mention is made of a cross of I.spuria X
Tet. La giving 104 seeds with seven germinations.
It remains to be seen whether CREOLE RHAPSODY is a cross between
virginica or spuria. Marie said it had upright standards, which sounds
Enid Lake, MS 7/8