Re: surflan and DNA content
- To: hosta-open@mallorn.com
- Subject: Re: surflan and DNA content
- From: h*@open.org
- Date: Sat, 27 Mar 1999 11:03:37 -0800 (PST)
Ben:
>I use it as a simple way to find out or the hybrids of the tetraploid
>ventricosa with any other diploid plant are really triploid as they
>should be.
I don't think there is any higher plant genera where you can't find
unreduced gametes IF you look for them. In some genera if you cross a
diploid with a tetraploid you do get triploids, but in other plants
there is triploid block, so any seeds that are produced from diploid x
tetraploid crosses are tetraploids from a unreduced gamete from the
diploid fertilized with the reduced gamete from the tertaploid - any
triploids that form are aborted. There are supposely two species of
hosta that are tetraploids, so it should be possible to check for the
presence of unreduced gametes. Do you know if unreduced gametes are
present in hostas, maybe at a very low level, and do you know if
hostas have triploid block?
There is, however, the question as to if tetraploid hostas have any
value. With a diploid chromosome count of 60 we can surmise that
hostas are probably already amphidiploids. Experiments on repeated
doubling of chromosomes has shown that plants only tolerate so many
chromosomes. You don't find too many plants with chromosome counts of
over 100. With a chromosome count of 120 in a tet hosta there is a
very high chance that all sorts of chromosome abnormalities will
arise. These abnormalities might not effect the plants ability to
grow and survive, but it sure could mess up fertility in later
generations.
Joe Halinar
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