colchicine used to improve vegetable crops

[Peter J. Walker]

chris freeman (cfreeman at frontiernet.net) wrote:

: I don't know alot about colchicine, but I know that it is used for 
: inducing mutations.  Basically, any experiment involving it will bring 
: out mutations, many undesirable, and hopefully a few desirable ones.  
: These desirable specimens can then be cloned and bred. Many household 
: substances can be used for mutation breeding as well:  coffee and 
: aspirin are good ones to try.  Be sure to soak seeds in water before 
: introducing mutagenic agents or the seeds may be killed.

Just to clarify: Colchicine acts during meiosis or mitosis to disrupt
formation of spindle fibers, preventing the proper separation of
homologous chromosomes and leading to changes in chromosome number.  (I do
not believe it induces other types of point mutations or changes in
chromosome structure.) Increasing the ploidy level of a plant often
results in phenotypically normal plants, but ones that are much larger and
more vigorous than the parental variety. I practice, I do not think you 
need to select advantageous mutations. (But, then again, I don't really 
know anything about plant breeding.)

Aspirin or coffee act very differently, inducing point mutations at the 
nucleotide level. In this case, the induced mutations are essentially 
random and you would need to select those strains that carry a desirable 
trait.

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Peter J. Walker
University of Vermont, Department of Botany,  Burlington, Vermont 05405-0086
Internet:	pwalker1 at zoo.uvm.edu
Telephone:	802-656-3221
Fax:		802-656-0440
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