Re: HYB: genetics questions
iris@hort.net
  • Subject: Re: HYB: genetics questions
  • From: R*@aol.com
  • Date: Sat, 5 Jun 2010 13:57:23 EDT

Some hybridizers do not believe in back crossing for all kinds of reasons.  
I do backcross if the previous generation has what is missing in the 
seedlings.  There are many genetic factors involved in the size of flower not just 
a few.  Your two parents might have had large flowers for different genetic 
reasons.  Crossing them might have diluted both sets of genetic factors 
resulting in small  flowers. Back crossing to one or both parents might give a 
fighting chance of  recovering size. If you could get a full set of genetic 
factors for large  flowers from both parents, you might have seedlings with 
very large flowers  indeed.
Fred Kerr
Rainbow Acres
 
 
In a message dated 6/5/2010 9:51:33 A.M. Pacific Daylight Time,  
iris-owner@hort.net writes:


iris  DIGEST          Saturday, June 5 2010     Volume 01 : Number 1070



In this  issue:

[iris] re: HYB: genetics  questions....
[iris] HYB: genetics  questions....
Re: [iris] HYB: genetics  questions....
Re: [iris] re: HYB: genetics  questions....

----------------------------------------------------------------------

Date:  Sat, 05 Jun 2010 07:48:43 -0500
From: Linda Mann  <lmann@lock-net.com>
Subject: [iris] re: HYB: genetics  questions....

Steve, like Christian, I'm no expert, but also as  Christian says, 
generally, it's not a good idea to try to get back a trait  that's lost 
to the F1, mostly because there are so many other traits that  have to 
line up just right at the same time.  My guess is that if you  are 
working with strongly inbred lines where all the other traits are  pretty 
uniform in the parents and seedlings, and there is just one trait  you 
are trying to recapture that got lost, it might be worth it.  But  I 
dont' really know.

Trying to increase flower size on seedlings is  something I've been 
attempting also, working with some of the really tough  rebloom lines 
here - IMMORTALITY and HARVEST OF MEMORIES.  Both are  highly prone to 
giving small flowered seedlings, but not always.  If  I ever had a small 
flowered seedling from these lines that also summer  bloomed here, I 
might try to work with it, but my impression so far is  that it's a trait 
that seems to follow along with 'weedy' median type  growth.  And having 
grown on a few of them for more than a year just  to see if they would 
rebloom, have decided that's really a waste of space  and am tossing them 
as soon as they bloom now.

An added issue with  bloom size is that it can be so strongly affected by 
growing  conditions.  Some (esp the west coast/Oz) intros often have both  
stalks and blooms miniaturized here - cute, but not looking like TBs.  
Seems to result from inadequate moisture/too much heat right  
before/during bloom season.  They look like MTBs - registered at 36"  
tall, but only about 18 to 20" tall here, with blooms in proportion to  
the stalk.

Which makes it hard to evaluate seedlings.  I have  used some of these 
for pollen, and so far, while form of seedling bloom  isn't bad, none so 
far have had what I would call large (i.e. Schreiner  sized) blooms.

Hope that helps a little.

In this group (and from  hybridizers), it's been a lot easier to find out 
about inheritance of  pigments and their patterns than about inheritance 
of other traits like  stalk height, bloom size, disease resistance.  Let 
me know if you  find out more specific information.

Or if you have room to do some  experiments, let us know what you learn!  
;-)

Linda Mann east TN  USA zone 7

------------------------------

Date: Fri, 4 Jun 2010  10:45:05 -0700 (PDT)
From: mahlberg s  <s_j_mahlberg@yahoo.com>
Subject: [iris] HYB: genetics  questions....

Hello all,
I have been dabbling for a few years now  with iris hybridizing.
I am gathering a better understanding of some of the  things that are 
happening
genetically.
My question is more for the more  seasoned hybridizers who have done many
different crosses.
What I am  wondering is, before making more crosses with potentially   
'compost
flowers', how much of the grandparents genetic material will be  passed to 
f2
if f1 is inferior to the parents. Will I just keep watering  down the 
genetic
material?
example, I cross two large flowered TBs, ''a  with b'' and end up with 
''c'' a
smaller flowered and differently colored  flower which is definitely not a 
show
stopper, is it potentially worth  backcrossing or outcrossing ''f1 c'' to 
try
and grab any of the granparents  genes in f2 seedlings? Or is it a compost
flower and just continue to work  with different seedlings that show
improvements over the parents.
I am  not certain if grandparents coloration would show up in f2 or if the
larger  flower size of grandparents might show back up in next generation 
if I
use  f1 in a cross, even though f1 is showing a smaller flower.
right now I am  working on flower size in some of my seedlings, but need a 
bit
more  insight.
thanks!
Steve M. zone 4b Northeastern  MN



------------------------------

Date: Fri, 4 Jun 2010  16:03:55 -0700 (PDT)
From: christian foster  <flatnflashy@yahoo.com>
Subject: Re: [iris] HYB: genetics  questions....

Well, I'm not a seasoned hybridizer, but...    In general it is considered 
a waste of energy to work with breeding stock that  does not display the 
traits you are trying to breed into the  offspring.





________________________________
From:  mahlberg s <s_j_mahlberg@yahoo.com>
To: iris@hort.net
Sent: Fri,  June 4, 2010 1:45:05 PM
Subject: [iris] HYB: genetics  questions....

Hello all,
I have been dabbling for a few years now  with iris hybridizing.
I am gathering a better understanding of some of the  things that are 
happening
genetically.
My question is more for the more  seasoned hybridizers who have done many
different crosses.
What I am  wondering is, before making more crosses with potentially   
'compost
flowers', how much of the grandparents genetic material will be  passed to 
f2
if f1 is inferior to the parents. Will I just keep watering  down the 
genetic
material?
example, I cross two large flowered TBs, ''a  with b'' and end up with 
''c'' a
smaller flowered and differently colored  flower which is definitely not a 
show
stopper, is it potentially worth  backcrossing or outcrossing ''f1 c'' to 
try
and grab any of the granparents  genes in f2 seedlings? Or is it a compost
flower and just continue to work  with different seedlings that show
improvements over the parents.
I am  not certain if grandparents coloration would show up in f2 or if the
larger  flower size of grandparents might show back up in next generation 
if I
use  f1 in a cross, even though f1 is showing a smaller flower.
right now I am  working on flower size in some of my seedlings, but need a 
bit
more  insight.
thanks!
Steve M. zone 4b Northeastern  MN

------------------------------

Date: Sat, 5 Jun 2010 15:03:12  +0200
From: "loic tasquier" <tasquierloic@cs.com>
Subject: Re:  [iris] re: HYB: genetics questions....

Hello Linda,

what a same  we can't exchange our seedlings:
i toss the big flowered ones and you toss  the small flowered ones!
i would especially love to get the ones that  rebloom in the summer!

It would save me a lot of  work!

Loic


----- Original Message -----
From: Linda Mann
To: iris@hort.net
Sent: Saturday, June  05, 2010 2:48 PM
Subject: [iris] re: HYB: genetics  questions....


Steve, like Christian, I'm no expert, but also  as Christian says,
generally, it's not a good idea to try to get  back a trait that's lost
to the F1, mostly because there are so many  other traits that have to
line up just right at the same time.   My guess is that if you are
working with strongly inbred lines where  all the other traits are pretty
uniform in the parents and  seedlings, and there is just one trait you
are trying to recapture  that got lost, it might be worth it.  But I
dont' really  know.

Trying to increase flower size on seedlings is something  I've been
attempting also, working with some of the really tough  rebloom lines
here - IMMORTALITY and HARVEST OF MEMORIES.  Both  are highly prone to
giving small flowered seedlings, but not  always.  If I ever had a small
flowered seedling from these  lines that also summer bloomed here, I
might try to work with it,  but my impression so far is that it's a trait
that seems to follow  along with 'weedy' median type growth.  And having
grown on a  few of them for more than a year just to see if they would
rebloom,  have decided that's really a waste of space and am tossing them
as  soon as they bloom now.

An added issue with bloom size is that  it can be so strongly affected by
growing conditions.  Some  (esp the west coast/Oz) intros often have both
stalks and blooms  miniaturized here - cute, but not looking like TBs.
Seems to result  from inadequate moisture/too much heat right
before/during bloom  season.  They look like MTBs - registered at 36"
tall, but only  about 18 to 20" tall here, with blooms in proportion to
the  stalk.

Which makes it hard to evaluate seedlings.  I have  used some of these
for pollen, and so far, while form of seedling  bloom isn't bad, none so
far have had what I would call large (i.e.  Schreiner sized) blooms.

Hope that helps a little.

In this group (and from hybridizers), it's been a lot easier to find  out
about inheritance of pigments and their patterns than about  inheritance
of other traits like stalk height, bloom size, disease  resistance.  Let
me know if you find out more specific  information.

Or if you have room to do some experiments, let us  know what you learn!
;-)

Linda Mann east TN USA zone  7

------------------------------

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