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Re: Re: HYB: breeding strategies
iris@hort.net
  • Subject: Re: Re: HYB: breeding strategies
  • From: Chuck Chapman <irischapman@aim.com>
  • Date: Mon, 31 Oct 2011 09:37:47 -0400 (EDT)

A suggested breeding plan

Keep in mind that this is a long term goal. So don't select seedlings? for
further breeding based on having best traits in each seedling. As you have
noted, you can trap yourself into keeping bad traits.

Probably should have three lines. One for rebloom, one for? beauty and one for
plant growth.? Lines A, B & C.That is choose seedlings based on a primary
goal, keeping other traits secondary in choice.

Maintain these lines for three generations. Them pick best? based on all three
traits? and cross your lines.? That is A X B, B x C. B X C .? Discard? the
line that has least potential, but can keep a few promising individuals for
crosses. But pick? to go forward with lines that combine best traits?
consistently ( most good seedlings)

Always choose fastest growers over slower growers and the ones with lowest
mature leaf count over those with higher leaf count (all other traits being
close)

Then after two or three more generations of? line breeding, cross your two
remaining lines.? Use thes plants to go forward.

In the meantime you will have made other relevant crosses. So should have?
seedlings to combine towards plants having best of all traits yopu want.

Careful to not trap yourself into? recessive genes

Plants need to be mature before? they can respond to? bud? set temperatures.
So need to keep seedlings growing in next to, if not ideal growing
conditions.? Ie: watered, weeded. lots of space and? goof or amended soil.

Keep? min/max temperature records for your garden. Only by co-coordinating
these with flowering can you tell which are summer? rebloomers. Without these
records you may go through a summer without bud set temperatures until fall so
may not see summer rebloom as conditions were not appropriate.

For me , this was a year without warm enough nights? for summer rebloom, so
didn't get any. Well, except for my precociousispec-x? seedling of forever
Blue X aphylla This went ahead with its intense summer rebloom anyway.? but no
rebloom on dependable Immortality and Queen Dorothy and ilk.? Only one grower
in south Ontario had rebloom on Immortality, and it was very late fall.

Chuck Chapman







-----Original Message-----
From: Linda Mann &lt;lmann@lock-net.com&gt;
To: iris &lt;iris@hort.net&gt;
Sent: Mon, Oct 31, 2011 8:45 am
Subject: [iris] Re: HYB: breeding strategies




:-)  or maybe that should be ;-(

I appreciate your and Betty's thoughts on this.  Yes, it's all abstract,
but I've been so submerged in the specifics of trying to figure out
possibilities and probabilities, that I haven't really been thinking as
much about some of the generalities.  As I'm potting up the seeds that
have been in the fridge stratifying, I've been thinking more about what
you've said about line and back-crosses, realizing that some/many of
these crosses really aren't particularly likely to move me towards my
goals.

One of the frustrations about breeding for rebloom (at least for me, and
I think for others too), is that it seems like the probability for
'summer'/recessive rebloom [in my growing conditions] &lt;ought&gt; to be very
high in a cross between two 'summer's (Betty's (1) type cross), but in
reality, it's very low.  There are a lot of other growth? traits that
have to be present along with the summer/recessive rebloom trait, and
thinking about it now, it seems 'obvious' that a better way to put
together those packages of traits is in back crosses or line breeding.

Last year is the first time I made a bunch of back crosses to IMM.  I
didn't want to do it, because it is going backwards in form, plus
getting more doses of genes that will give me a bunch of white flowers
with no way other than test crosses to get back to any kind of
interesting color and pattern.

On the other hand, Betty's 'kitchen sink' approach can also work - it's
the approach I've been working towards.   And that approach allows more
following of color, pattern, and form than backcrosses and line breeding
can allow at this stage of my breeding program.

&gt; It's not always a
&gt; simple matter to make a connection between what we read about breeding
and
&gt; the realities of figuring out what to do with a batch of seedlings that
&gt; aren't what we expected.

So far, it's mostly been a vague hope that this might happen, but the
best fertility/opportunities haven't been very modern parents.  But I
will keep occasionally working the best oncers descended from IMM with
an occasional back cross.  Another 10 yrs should do it.  I will still be
in my 70s, so maybe my wits will still be working enough to do this.

&gt; If you were
&gt; trying to combine two irises with very different virtues in the hope of
&gt; getting "the best of both", then I think it makes sense to go on for
&gt; another generation or two, even if the initial seedlings aren't better
than
&gt; the parents.

This is really helpful.  One of the problems with figuring out what to
do is that I've been breeding for 3 traits, not just two - rebloom,
pretty, and reliability/survival in my growing conditions.  You might
think that reliability and rebloom would be the same, but they aren't.  :-(

Now if I can just get more of the first generation that are fertile!
I've grown a &lt;lot&gt; of IMM X beauty seedlings (Betty's 3rd type of cross)
- most aren't fertile, most produce few surviving seedlings.  But I am
getting a lot of really pretty & vigorous 2nd generation seedlings from
(IMM x beauty) X another beauty (Betty, you don't  list this type of
cross - too far from rebloom?).  These seedlings combine two of the
traits I'm after.    Is that what you mean by going for another
generation?  So now it's time to make back crosses for the third trait?

&gt; My summary: if you are trying to combine very different parental traits,
it
&gt; makes sense to go for another generation at least, even if the initial
&gt; seedlings fall short. If the parents are similar and you're just hoping
for
&gt; improvement, and you get nothing inspiring, it might make sense to let it
&gt; go and try different crosses instead

Thanks again, Tom and Betty.

It can be a bit overwhelming...

Linda Mann east TN USA zone 7

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