Re: HYB: genetics questions....
iris@hort.net
  • Subject: Re: HYB: genetics questions....
  • From: i*@aim.com
  • Date: Sat, 05 Jun 2010 21:11:13 -0400
 A question that is a great question, but unfortunately does not have a simple
answer.

A problem that one has to answer based on what they see in their cross. I'm
assuming you are talking of  plant characteristics, not colour or pattern.

Before you can begin to answer, you need enough of a cross to reach bloom size
before you can see what spread of characteristics you get.  Each of the plant
characteristics will inherit differently. Some will be multi genetic , some
will be combinations , some will  be genetic interactions ,and many will be
environment-genetic potential interactions.  Branching will be separate from
bud count, separate from bloom sequencing. Separate from flower stalk height,
separate from height of branching, separate from number of flowers in a
socket, separate from flare, hanging, separate from round versus spatulate,
separate from haft width, separate from sun fastness, separate from cold
hardiness, separate from number of increases etc endlessly.

Some will have little variation in cross, some will have wide variations. All
will have a bnormal distributionb curve.

If size of flower is large in both parents, and small in , say all of 24
plants from same cross, then  you would have two different  gene sequences
working.  then you would need to have a working hypothesis. first, is it a
seasonal thing, plant maturity thing etc. If all other effects are accounted
for then  the genetics could  (not necessarily) be two different recessives,
and these genes could be picked up  in future crosses.

As part of your evaluation, should be multiple crosses of each parent with
other plants. Best if each is crossed to the same  other parents. that is , if
cross wondering about is A X B, then you should also have  A X C, B X C, A X
D, B X D, A X E, B X E etc. then you have some good ideas to go on.

Over all, it is best  to select  several plants and cross ones with competing
plant characteristics.

An example from a cross I made the other day.  Two different  seedlings with
pink standards and mauve falls, with red beards.

A has very large flowers, laced, and is very tall  with high branching. First
branch is almost 20" above ground.

B is relatively short, has small flowers, very low branching (6" above
ground), multiple buds and ruffling and no lace.
ps: A & B are cousins

Hopefully some of seedlings will inherit  a proper mix of genetics. Cross made
three times one way and two in reverse cross. This sort of cross is one that
works best if  you have a lot of seedlings to choose from. All of the
different combinations of plant  characteristics  will mean that there will be
many combinations, some with worst of each plant, some with best of each
plant. Many wrong combinations, only a few good ones.


Chuck Chapman












-----Original Message-----
From: mahlberg s <s_j_mahlberg@yahoo.com>
To: iris@hort.net
Sent: Fri, Jun 4, 2010 1:45 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







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