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HYB: Rolling the Dice

From: Sharon McAllister <73372.1745@compuserve.com>

Diana Louis wrote:

>  Approximately how many pods would you need to get 1000 seedlings from
>  say, your arilbreds, reciprocal crossing and all? Would this be enough
>  seedlings or too many? I know it depends on how many seeds there are per
>  pod and that depends on how good the pollen parents and pod parents
>  amoung other etcs. 

Lots of 'etcs' on this one!

To start with, I've never tried to raise 1000 seedlings from a single cross
-- or even a pair of reciprocal crosses. The corresponding Rule of Thumb in
arilbreds is that 1 in 50-100 seedlings in an experienced hybridizers'
patch will be worthy of introduction.  I got this number from several
experts, all of whom had been hybridizing at least 30 years, and when I
analyzed Gene Hunt's seedling records I was able to get supportive
evidence.  I run the numbers on my own introductions AFTER all of my
seedlings from an individual hybridizing season  have been evaluated and
selected or discarded.  I don't have a goal of a certain number of
introductions, but find this an interesting measure of my progress as a
hybridizer.   I broke the 1 in 100 barrier about 10 years after I turned
from fun-with-pollen-daubing to serious-about-hybridizing -- which I
attribute to a lot of help from my mentors.  

So I'm going to re-state the question a bit differently:  how many pods
would you need to get enough seedlings to effectively explore the potential
of a cross?

With the wide crosses, it just isn't going to happen.  Even using the same
pollen parent for every flower in the whole row of a prospective pod parent
and culturing the resultant seeds, I've rarely managed to get more than 20
seedlings.   This is enough to show the potential of a cross, but not to
explore it thoroughly.  Mostly, it helps me identify the best parents for
the type.

With halfbred X halfbred crosses, it's not at all unusual to get more than
50 seedlings from a single pod, but many will succumb before they reach
bloom size.  By tagging each stalk I cross rather than the individual
flower, and then using the same pollen parent on later-opening flowers, I
can sometimes bloom 50-100 siblings.   I would say, however, that 25 to 50
siblings is more typical in my patch.  

We can talk about the overall chances for success, but in the real world
some crosses produce several strong candidates while other crosses produce
nothing of note.  In one case, I may look at a set of 30+ sibs, find one
worthy of consideration and the rest so uniform that I see no reason to
repeat the cross to get more sibs.   In another, 30+ sibs may include
enough variations of pattern, color and form that I definitely want to get
more seedlings to explore the potential combinations.  

Hybridizing is a blend of science & art -- I just happen to have more fun
with the scientific part of it.

Sharon McAllister

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