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Re: HYB: 1/4 x TB Crosses


From: "Colleen Modra" <irises@senet.com.au>

Sharon

I'm enjoying this discussion as I do a lot of hybridising (mostly TB at the
moment) but am very interested in arils and AB. I need to know as much as
poss, stay on line.

Colleen Modra Oz
-----Original Message-----
From: Sharon McAllister <73372.1745@compuserve.com>
To: INTERNET:iris-talk@onelist.com <iris-talk@onelist.com>
Date: Monday, 15 November 1999 3:54
Subject: [iris-talk] HYB: 1/4 x TB Crosses


>From: Sharon McAllister <73372.1745@compuserve.com>
>
>Message text written by Donald Eaves:
>>
>
>>> but there have also
>>>been examples counted as having three TB sets of chromosomes and one set
>of
>>>mixed.
>
>>  It's this last that intrigues me.  Why wouldn't this begin to stack aril
>genes in
>a TB-like plant?  And why wouldn't you begin to line breed here?
><
>
>Unfortunately, I can cite several reasons:
>
>1.      It's extremely rare, detectable only through chromosome analysis
>[which is a tad more demanding than chromosome counting].
>
>2.      The mixed set of chromosomes is less likely to be passed on than
>normal sets, and detecting its presence in the next generation is just as
>difficult as finding it in the first place.
>
>3.      The gene pool is much too small for line-breeding to be practical.
>
>>  If you
>could
>accumulate more aril genes while maintaining TB hardiness, it seems that
>line breeding would be the means of doing so.  If I were doing it, it would
>be
>the plant I was after, not necessarily how it could be registered.  I
>realize
>that the genetic knowledge would be important, but I haven't grasped the
>whole picture somehow.  It seems to me that the proper selection of crosses
>which added more aril genes, even if only bit by bit, would move them
>toward
>being more accessible as garden subjects.  Those that picked up the less
>hardy or more difficult aril aspects could be discarded or used just as the
>ones currently are being used.  Fill me in on what I'm not seeing here.
><
>
>There's nothing wrong with your proposed scenario, except that it is
>subject to the limitations I outlined above and there are easier ways of
>accomplishing this objective.   The simplest is just selecting seedlings
>for growth habits as much as flower characteristics.
>
>For example, many years ago some of Gene Hunt's introductions were
>criticized for having "lost" their signals.  But signals are an onco trait,
>at that time still closely linked with onco growth habits.  Gene broke the
>link by developing lines with TB cytoplasm and plant characteristics [for
>example, WISHED FOR CHILD & KOKO KNOLL] or  regelia cytoplasm and plant
>characteristics [for example: ESTHER, THE QUEEN].  With outcrosses, he then
>reintroduced signals to these lines, while maintaining gardenability.
>
>Following up on his work, I found that plant characteristics tend to be
>most like those of the pod parent.  For example,  EQ gave me far more
>selected seedlings when used as a pod parent than a pollen parent, even
>though I was able to make many more crosses using its pollen.  That's why
>I've come to recommend choosing the pod parent for its expressed plant
>characteristics and genetic potential in flower characteristics.  I
>certainly don't claim a monopoly on this.  If you study some of Howard
>Shockey's last 3/4-bred introductions, which are exceptionally gardenable
>for the class,  you'll see that he also capitalized on this principle.
>
>My long-term experiments have also included attempts to accumulate as many
>TB genes as possible in a plant with aril cytoplasm, and vice versa --
>mostly to learn about the genetics.  [You might want to explore the Sibling
>Sheets on my web site to see more about this.]  But there have been enough
>payoffs that I can recommend this approach to others.....
>
>For a specific example, let's look at DRESS PINKS.  From (LOVELY BLANCHE x
>EUNICE) X SUNRISE IN GLORY, you might expect it to be a halfbred.  Nope.
>Its pod parent was a Hunt seedling, which appears to be triploid [its pod
>parent was a tetraploid TB and pollen parent was a diploid RC, so that's
>not surprising]. The Hunt seedling wasn't introduced because its only aril
>characteristics are limited branching, low bud count and superior substance
>-- but it is a clear coral pink [the color that just "doesn't appear" in
>arilbreds] and has given me some spectacular seedlings.
>
>Coming from a triploid x amphidiploid cross, DRESS PINKS could be either of
>the parental types.  Extensive testing, however, convinced me that it is a
>triploid of limited fertility.  That means it gave me a significant number
>of seedlings, but not nearly as many as I'd expect from a halfbred.   The
>plants are quite TB-like, although it performs better for me than any TB.
>When I saw it in Lu Danielson's more hospitable-to-TBs garden, it was
>threatening to take over the place.
>
>So what does this mean for future generations?  Even with its limited
>fertility, it's an excellent pod parent for use with half-breds.  That type
>of cross takes advantage of its ability to pass on its growth habits, with
>a 50/50  chance of fertility in the first generation.  Careful selection of
>its mate can also capitalize on its recessive color & pattern.  [Yes, it
>even has a small signal patch.]
>
>That's not to say that DRESS PINKS is the ONLY one of its type worth using
>in such a program -- this is just one example.  IMO, any quarterbred with
>good growth habits and receptive-to-aril flower characteristics is worth
>trying as a pod parent with halfbred pollen.
>
>>  In a way, didn't Mr. Seligmann achieve exactly what aril breeders were
>looking for with SATAN'S MISTRESS?  It's got intense color saturation,
>strong substance, superior texture on a gardenable plant much like a
>TB.  It just didn't have the onco appearance.  But it doesn't quite look
>just like the TBs either, tho it's difficult to pinpoint exactly why.  It
>has
>somehow to do with the above, but I can't quite explain what it is.  Still
>it is a remarkable iris and is selected as THE standout even by visitors
>here when it is in bloom.  Without any prompting.  Something is visible
>even to the untrained eye or that wouldn't happen.
><
>
>Yes, in that sense SATAN'S MISTRESS was a success.  But he registered it as
>a TB because it didn't have the aril traits most people had come to expect.
> The Coronel was a self-professed "pollen dauber".  He enjoyed raising a
>variety of seedlings and showing them off to garden visitors.  His
>arthritis had progressed to the point that he was reconciled to giving up
>hybridizing about the time I got serious about it so we started working
>together.  Sometimes, it seemed like he put up with my study of pedigrees &
>planning of crosses only because I'd make whatever crosses he wanted before
>spreading my own selections on the remaining fresh flowers in his garden --
>but we certainly had fun.  Another MVIS member also stopped by frequently
>to make crosses for him, and I still believe their prime consideration was
>coming up with outlandish crosses that would get the biggest "rise" out of
>me!
>
>>   Soooo, that
>means more planning. It's likely that at age 52 this just ends being an
>exercise for fun, but I can make it serious fun.
><
>
>IMO, you still qualify as a youngster!  One of the last letters I got from
>Gene Hunt outlined a program he found interesting, "but it would take 40
>years".  At the time, he was in his mid-70s -- but he closed that letter
>with "I may try it anyway"!  Unfortunately, he never got the chance as his
>life was soon ended by an unfortunate encounter with a drunk driver.  But
>he had taken the time to think it through and tell me about it, so I was at
>least able to follow through on the portions for which I could find the
>requisite breeding stock.
>
>>   May I begin with the above?  If not, what's the best approach
>for the first generation end-of-line scenario?
><
>
>I've tried to answer the above questions, but the approach I'd recommend
>for a first-generation, end-of-line scenario is relatively simple:  Follow
>the advice I've given before regarding the production of quarterbreds with
>aril characteristics.  The TB x halfbred cross and its reciprocal produce
>quarterbreds in sufficient quantity for evaluation and selection.  The TB x
>quarterbred cross and its reciprocal produce fewer seedlings and only half
>of them can be expected to be quarterbreds.  The odds are worse, but the
>underlying principles are the same.  The added challenge is simply that of
>determining WHICH of the offspring are actually TBs and which are
>functional quarterabreds.
>
>1.      Early-season rebloomers not only have desirable growth habits but
>also provide an opportunity for a reciprocal cross. In conventional crosses
>for quarterbreds, I've found the highest ratio of good seedlings in crosses
>with an arilbred pod parent but have introduced more with a TB pod parent
>simply because I've had so many more to choose from.  If you want to learn
>as much as possible from these experiments, reciprocal crosses will be of
>enormous value.
>
>2.      Plicatas, bicolors, and bicolor-plicatas -- expecially those with
>pink ground -- are most likely to let aril traits show through. The plicata
>pattern is recessive.  Pink is recessive.  Bicolors are a combination of
>dominant and recessive genes.  These patterns are more likely to let aril
>characteristics be expressed in their offspring than are selfs -- even
>light-colored ones that owe their appearance to the presence of a dominant
>inhibitor.
>
>I've answer on-list because others saw your questions and may be interested
>in the answers.  I'll certainly continue the discussion off-list, if you
>prefer.
>
>Sharon McAllister
>73372.1745@compuserve.com
>
>

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