Subject: Colchicine and allopolyploid squash

From: [email-masked] (Beverly Erlebacher)
Date: Tue, 30 May 1995 23:04:26 GMT

Last summer I crossed Butternut (Curcurbita moschata) with Little
Gem (Cucurbita maxima) squash.  I had read that this interspecific
cross results in plants that set fruit well, but their seeds don't
develop completely, either crossed inter se or backcrossed to one
of the parent species.  I would like to use colchicine to try to make
an allopolyploid.

I'd like some advice on how to do this.  A pharmacist friend has
offered me some colchicine pills (0.6mg each).  I planted some
seeds in pots and have 16 healthy looking seedlings that are just
flattening out the first true leaf.  I would like to apply the
colchicine to the growing tip once another leaf has emerged, so 
if it kills the the tip, the plant can recover from an axillary
bud and I can have another try at it.

General or specific advice on using colchicine or other methods
would be appreciated, also any other comments on what I'm proposing
to do.  I have access to a university library, so may be able to
find references.  General plant physiology books usually mention
colchicine but don't provide details.  

Beverly Erlebacher
Toronto, Ontario Canada

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From: [email-masked] (Randy)
Date: Thu, 1 Jun 1995 16:45:05 GMT

Colchicine is extremelt dangerous and carcinogenic. It inhibits
microtubule formation and chromasome doubling by inhibiting division of
the cell into two daughter cells. If you use it be very careful and use
latex gloves. Chances are that you will not get it to work this way
effectively.

With canola we allow a nuber of nodes to form and then saok the roots for
1-2 hours to uptake the colchicine (1%). This usually leads to alot of
plant death but some of the auxillary buds will continue to grow and they
should be doubled.

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From: Gary Poyssick <[email-masked]>
Date: 3 Jun 1995 12:10:05 GMT

First, Colchicine is a very toxic substance -- be extremely careful 
using it.

You need to treat the seeds, not the plant. Make a weak (1%) solution. 
treat LOTS of seeds. Soak and let dry two or three times then plant.

If you get good germination, the treatment did not take. It should kill 
about 95% of the treated seeds. 1% of the 5% left MAY mutate.

Colchicine is used in orchid propagation, seeking tetraploid plants with 
large flowers and heavy substance. A VERY SMALL AMOUNT WILL KILL AN 
ADULT. REPEAT: A SMALL GRAIN of this stuff will kill you. If it gets in 
your food, on your fingernail, anywhere - in your eye, if you breath the 
dust, etc. It will kill you. Be careful. It is also a very powerful 
carcinogin.

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From: [email-masked] (Joe Trybyszewski)
Date: Tue, 06 Jun 1995 06:26:15 GMT

[email-masked] (Beverly Erlebacher) wrote:

>I'd like some advice on how to do this.  

First, if you are successful in changing the genetic structure from
mono to polyploid, I have heard you must use the seeds from the
polyploid and grow those for a second generation before any part of
the plant is consumed.  i.e. the first generation must not be eaten.

I'm not certain this is correct.

Joe Trybyszewski