Date: Sat, 21 Oct 2000 09:26:17 -0700 From: Ivan Snyder <bioexp@juno.com> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg3036$foo@default> Subject: re: Drosera Hybrids / Ping test
>While the talk on Drosera hybrids is up, has anyone hybridised Drosera
>peltata and D. auriculata?
>Miguel de Salas
Hi Miguel and all,
I crossed these two sundews. I'm sure I did make a hybrid since I took
seed from the green peltata parent and got offspring having much red
color as in the auriculata parent. The hybrid would not make seed, though
may have only had defective pollen. I never used good pollen from another
plant to test it. I have had other intraspecific hybrids of different
forms of spatulata as well as brevifolia which were fully fertile though
had bad pollen.
On the matter of induced polyploidy, I colchicine treated D. x beleziana
(D. rotundifolia X intermedia) and probably did make a fertile plant.
Problem was I could not get the thing to flower. I have found that it is
best to treat only freely flowering tropical hybrids such as I did with
my fertile octoploid D. x nagamotoi (anglica Hawaii X spatulata
Australia). For those of you that may want to breed sundews and change
ploidy and get a fertile hybrid, I have figured a way in which you can
that does not make use of any dangerous chemicals. If you cross pollinate
the hexaploid D. tokaiensis with the diploid D. spatulata from New
Zealand, in theory you will get fertile (with defective pollen) offspring
which is tetraploid and close enough to be compatible with the tetraploid
spatulata from Australia. I have not done this very cross myself, but
have done enough similar crosses to be confident that it would work. I
will demonstrate the cross diagrammatically below as in my CPN March 2000
article:
S > 10 spatulata chromosomes, R > 10 rotundifolia chromosomes
S S R S S S S S
-------- X --- > ------ , ------
S S R S S R S S
tokaiensis X spat NZ > spat Aust
You can see in the diagram that a hexaploid (or 6-ploid) crossed with a
diploid (2-ploid) makes a tetraploid (4-ploid). In crossing, a half set
of chromosomes from the allopolyploid D. tokaiensis -SSR is combined with
a half set from the spatulata NZ -S, makes a similar pairing as seen in
the Australian spatulata SS/SS. This sort of retroploid crossing could
also prove to be an important tool in testing ping taxonomy, and could be
done by most of us amateurs; we too can do important science. For
instance Pinguicula bohemica is thought by some to be a tetraploid P.
vulgaris. If the two species are in fact equivalent but have only
different ploidy, then by crossing the octoploid P. vulgaris with
tetraploid P. bohemica, a fertile hexaploid should result.
Ivan Snyder
Hermosa Beach
California
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