Re: hosta-open DIGEST V1 #985
- To: hosta-open@mallorn.com
- Subject: Re: hosta-open DIGEST V1 #985
- From: h*@open.org
- Date: Fri, 13 Oct 2000 09:45:24 -0700 (PDT)
Mike:
>I have been working with some crosses this year trying to mix
>Tretraploidi hosta with the standard Diploidi type.
Some plant genera have what is called triploid block. When you cross
a tetarploid with a diploid you would expect a triploid, but with
triploid block the triploid embryos abort. Supposely, Ben Z. has done
some ploidy level studies with hostas, but hasn't presented any of the
data on this robin. I believe his studies revealed at least some
triploids, but the presence of triploids in a genera that has triploid
block doesn't invalidate triploid block. Potatoes have a strong
odd-ploidy block - triploids and pentaploids. Potates are either
diploid, tetraploid or hexaploid. There is actually a genetic
mechanism for this breakdown in triploid block, but it's difficult to
understand. If you cross diploids with tetraploids and consistently
do not get any seed set, then you can expect triploid block.
Daylilies have triploid block, but true lilies, genus Lilium, does not
have triploid block. If you do have triploid block and cross a
diploid with a tetraploid and get seeds, then the diploid is producing
unreduced gametes and acting like it is a tetraploid, and thus will
produce tetraploid progenies. If you do have a triploid it is better
to use it as a pod parent then as a pollen parent. Many triploids
will produce a few viable egg cells. I'm not sure about hostas, but
in lilies triploids used as a pod parent usually do the best when
pollinated with tetraploid pollen.
Joe Halinar
---------------------------------------------------------------------
To sign-off this list, send email to majordomo@mallorn.com with the
message text UNSUBSCRIBE HOSTA-OPEN
