Re: HYB: ?traits/thoughts
- Subject: Re: [iris] HYB: ?traits/thoughts
- From: D*@cabq.gov
- Date: Sat, 8 Nov 2003 09:03:52 -0700
- List-archive: <http://www.hort.net/lists/iris/> (Web Archive)
4) STALK HEIGHT (in rebloomers) - This is by no means an answer, but
rather a thought. Maybe this is all worked out already? I don't know the
lineages of TB rebloomers very well, but is it not true that most of the
early rebloomers involved dwarf or intermediate species and hybrids (mostly
I. pumila, I. lutescens, and other 16, 32, 40, and 44 chromosome types -
all of which have some ancestry from the 16/32 chromosome group)? Isn't
also true that the largest proportion of rebloomers are not TB's but rather
SDB's or IB's (mostly 40 and 44 chromosomes)? Perhaps this accounts for
some of the tendency towards shortness in TB rebloomers? Maybe the genes
responsible for reblooming come mostly from short species, and maybe you
get "short" genes connected to "reblooming" genes?????
My guess is that when you combine the genetics of a TB (12/24 chromosomes)
with the genetics of a dwarf (16/32 chromosome) plant, that it sets up some
sort of "problem" in the plants seasonal responses that fools it into
blooming at the wrong time. Perhaps the two groups do not have seasonal
responses controlled by entirely the same genes? Or, perhaps the responses
have evolved to react to different trigger mechanisms? etc., etc.? I'm
not sure if the trend holds, but I've noticed a few TB rebloomers that
I've looked up counts for to have a slightly low number of chromosomes
(fewer than 48; more than 44), which implies dwarf ancestry somewhere in
their past.
Dave
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