hort.net Seasonal photo, (c) 2006 Christopher P. Lindsey, All Rights Reserved: do not copy
articles | gallery of plants | blog | tech blog | plant profiles | patents | mailing lists | top stories | links | shorturl service | tom clothier's archive0
 Navigation
Articles
Gallery of Plants
Blog
Tech Blog
Plant Profiles
Patents
Mailing Lists
    FAQ
    Netiquette
    Search ALL lists
    Search help
    Subscription info
Top Stories
Links
sHORTurl service
Tom Clothier's Archive
 Top Stories
Disease could hit Britain's trees hard

Ten of the best snowdrop cultivars

Plant protein database helps identify plant gene functions

Dendroclimatologists record history through trees

Potato beetle could be thwarted through gene manipulation

Hawaii expands coffee farm quarantine

Study explains flower petal loss

Unauthorized use of a plant doesn't invalidate it's patent

RSS story archive

RE: SPEC-X: Christy's seedlings


From:  Bill Shear

Auurgh, here we go again.....

>>  Originally, the cross was reported as having been made BOTH ways, now 
as JI X Sib only.<<
Perhaps you misunderstood. I have said all along that I used pollen from 
*both* Siberians on *both* JIs. FYI, my notes from 1992 show that both JIs 
set seed.
  >>  Now if it was JI X Sib only, it becomes very difficult to explain, <<
Which is exactly the reason I've been trying to enlist the help of as many 
skilled people to find out as much about these plants as I can. Know any 
volunteers?
>>  A survey of wide-cross progeny in the history of iris breeding shows 
that the F1 generation is almost always a mix of the characteristics of 
both parents.<<
Not necessarily. I've heard hybridizers speak of dozens of crosses that 
should have been perfect but show no hybrid characteristics. The knee-jerk 
reaction is to throw the whole lot on the compost because they don't fit 
the stereotype. Anything that might have been learned is lost.
>>The evident easy fertility of both the original cross, repeated several 
times, and the offspring with the parents and among themselves, also does 
not fit what we know of plant genetics. <<
Then, perhaps we just don't know as much as we think we do about plant 
genetics.
I am still testing to try to find out who likely came from which exact 
pairing. The seedlings *will* cross easily with their own kind. To be 
perfectly clear... There are 2 distinct kinds of SIB types suggesting 
different parentage. *In controlled crosses*, the SIB types will cross to 
SIB types and the easiest crosses will be those who have exactly the same 
parents in common. They will not cross as easily to related pure Siberians 
and I have not been able to cross them at all to unrelated Siberians.
The JI types show the same kind of behavior.
I have gotten only 1 cross of opposite type F1s and am seeing reasonably 
consistent takes using JS-C pollen on the SIB type F1s. Crosses to pure JIs 
have shown no positive results except for ROSE QUEEN. Since pure JIs do not 
tolerate our heat and drought well, I have had few chances to try such 
crosses.
>> Wouldn't you reasonably expect that from types as divergent as JI and 
Siberian, which have never been crossed before in the history of iris 
breeding, the progeny would be sterile or almost so?<<
Indications are that as the seedlings are becoming more balanced in 
appearance they are also becoming less fertile. The seedlings from the 
cross of 92JS2A and SUMMER SKY are nearly all sterile.
>>  The chromosome counts (at least one of them) suggest intermediacy,<<
*One* count showed only 24 C as is common with JIs. The other *three* 
showed 26 C.
 >> cytogeneticists routinely repeat such counts many times.  Was Sam's 
count from one cell or did he survey several cells and root tips (assuming 
the count was made using root tip cells)? <<
The counts were made using root tips and Sam told me he repeated them a 
number of times to be certain they were correct. I have the Polaroids of 
the clearest of those spreads.
 >>The 26-chromosome plant should certainly be sterile or have limited 
fertility with either parent, because it would produce 13-chromosome 
gametes, and in crosses with either parent there would be a univalent 
(unpaired chromosome).<<
Fertility *has* been limited in parent X seedling and seedling X parent. It 
could also explain the high mortality rate in those crosses.
>> was dismayed at the quotes from "The Experts Speak," a mischievious 
little book that suggests that "experts" are usually wrong,<<
Lighten up! I tossed it in to underline the fact that experts are not 
always right just as novices are not always wrong. Judgements, by anyone, 
can only be made using the facts available at the time. When new 
information surfaces that doesn't seem to fit, I would rather find out why 
than simply discard the information and cling to the safety of established 
ideas. How many of the people quoted would be considered experts today if 
they had stopped searching for an answer because a guess was wrong or 
because conventional wisdom at the time said something was impossible.
>>When the original crosses are repeated by a second hybridizer or even a 
third or fourth, under rigorously controlled conditions and repeated 
chromosome counts or intermediate appearance and limited fertility confirm 
the results, I'll be happy to switch.<<
Let me see if I have this straight....
Someone else.. a REAL hybridizer (or 2 or 3) must duplicate the cross under 
laboratory conditions and have C counts done repeatedly.
If these plants had looked intermediate and were sterile from the first, 
they would also have offered no chance to learn, no chance to develop new 
types, and no challenge to those who believe there is more to learn of 
genetics than is already on the books.
As frustrating as it's been at times, I'll go with the chance to learn 
something new rather than settle for immediate gratification and plants 
which are genetic dead ends.

Christy Hensler
THE ROCK GARDEN
Newport, Wash.
http://www.povn.com/rock/




-------------------------- eGroups Sponsor -------------------------~-~>
Hate housework?...then WIN A MAID....
http://click.egroups.com/1/7009/0/_/486170/_/967487146/
---------------------------------------------------------------------_->







 © 1995-2015 Mallorn Computing, Inc.All Rights Reserved.
Our Privacy Statement
Other Mailing lists | Author Index | Date Index | Subject Index | Thread Index