HYB: Rolling the Dice
- To: Iris Talk Listserver
- Subject: HYB: Rolling the Dice
- From: S* M* <7*@compuserve.com>
- Date: Fri, 15 Jan 1999 16:32:54 -0500
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From: Sharon McAllister <73372.1745@compuserve.com>
Mike Sutton wrote:
> I have to agree with Lloyd. It seems that 1 in 1000 for a good seedling
is
> way, way too high. 1 in 100 is more like it. If there is not a lot of
> thought or research put into crosses then maybe 1 in 1000.
Sounds like we've gone through a shift in definitions somewhere in this
thread....
The 1 in 1,000 figure, which I obtained from TB hybridizers who had had
decades of experience, did not refer to merely "good" seedlings -- but ones
that made it through the entire evaluation process and were chosen for
introduction. A well-thought-out cross may produce a number of very good
seedlings, all of which are so similar that only the BEST one is
introduced.
Let's take a concrete example. Keith Keppel certainly meets my definition
of an experienced, and extremely knowledgeable hybridizer of TBs. He has a
reputation for producing good seedlings. Lots of them. At this point, I'd
guess that far more than 1 out of 100 would seem "good" to us. But not all
that are "good" are distinctive enough and show enough of an improvement in
Keith's eyes to be introduced.
Here's some more food for thought: Keith uses a seedling numbering system
that provides Year, Cross # and Selection Letter. True, that's not enough
information to determine how many seedlings he evaluated from that
particular cross in order to make those selections. The cross numbers,
however, clearly show that only a small portion of his crosses for a given
year produce any introductions at all.
The Rule of Thumb I cited is just that. No more. No less. We could come
up with a more accurate figure for a particular line by analyzing seedling
records -- if someone had the data and time to devote to the project. But
without records to analyze, I don't think that mere speculating is
fruitful.
Sharon McAllister
73372.1745@compuserve.com
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