Re: isolation distance for pure seed
- To: i*@yahoogroups.com
- Subject: Re: [iris-species] isolation distance for pure seed
- From: "greg davis" g*@novocon.net
- Date: Tue, 14 Mar 2006 19:20:26 -0800
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Marielle
I don't know of published experimental work on versicolor.
However, opinion based on years of experience with
garden selected clones and wild populations, follows.
Pollen is vectored aggressively in versicolors, ( favoring
outcrossing ), by more than one kind of bee. Self pollination can also take
place very early in flowering, depending on timing of pollen dehiscence, so
neither outcome is certain. Since bees forage aggressively across the
countryside at this time of the year, on the order of miles, isolation
is not practical. Bloom season is also very
concentrated preventing time isolation as an effective option.
For these reasons one must conservatively conclude that
controlled hand pollinations are necessary.
Hand pollination experience also indicates hand made
selfs set seed at lower rates than hand made
inter-population pollinations. This suggests self compatibility
mechanisms may be influencing pollination success rates of the
two pollen sources. The logical outcome of this would be outcrossing
favored in nature and continuance of native bloom color. That is in fact
what happens. Native stands seldom have alternative bloom color, such
as pink - the dominant native blue maintains. Theoretically
this occurs because high outcrossing rates severely restrict
recombination of recessives that might be present in the
population. Recessives are necessary in both parents for pinks and
other colors to appear.
I'm afraid hand pollinations are your only option for high
purity.
Others may have different opinions.
IRISMAN646
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