From: toby@milton.u.washington.edu (Toby Bradshaw)
Subject: Re: plant phys use in breeding
Organization: University of Washington, Seattle
Date: Wed, 9 Sep 1992 16:06:16 GMT

>Steve Modena:
>I'm not impressed that RFLP analyses or RAPD's are the solution to
>much....and I've said so previously in this forum.

The solution to marker aided selection?  Have a talk with
Ron Sederoff in your forestry department.  They've already
found a RAPD linked to the "nectarine" phenotype in peach.
Since it's a recessive, and cannot be ascertained until
maturity, early selection could be done at the seedling
stage for about a dime per tree.

This is a small, perhaps trivial use of markers.  What they'll
really be used for is to clone relevant QTLs for many traits,
and work from there by breeding or biotech.

>Again it's
>the numbers: what does it cost to do the gels, what are the start up
>costs, and picking probes (or primers, in the case of RAPDs) is a
>problem in maize (maybe it's easy in alfalpha or whatever).

Similar complaints were made about hybrid seed corn.  


>Argument against: traditional quantitative techniques (plant height;
>harvest index; etc) plus better exploitation of untested germplasm
>will make more progress sooner for "less money" while retaining a traditional
>breeding regime and work atmosphere that is well respected and not
>quite so dangerous to one's career and maeger budget allotment.  

OP corn used to be traditional, too, and costs less than controlled
crosses.  It's the return on investment that counts, not just the
up-front costs.

>Well, in the sense that an F-15 has
>computers that read lots of sensors and accelerometers and adjusts
>all the trim tabs and modifies stick response......'cuz, Folks,
>those jets are NOT aerodynamic in the sense that a glider is...
>and would and do crash forthwith when those computers go to "sleep."

Don't believe everything you read.  The F-15 is statically stable,
with the CG forward of the CL.  The X-29 is statically unstable,
though, and can't be hand flown.

>(Don't believe it?  Remember how the back-seater died in Top Gun?)

I wouldn't cite Hollywood for my technical information :)  The
F-14 supposedly spun in the wake turbulence of another aircraft.
Spins are aerodynamically stable flight modes in many aircraft.
Some spins are recoverable, some are not.  All fighter aircraft
I know of (including the F-14) can be spun and recovered given
sufficient altitude (sometimes in excess of 10,000 feet).  Spins
can be disorienting, especially inverted spins, and are not
performed as part of routine training in every fighter because the
recovery may involve some extreme measures (like deploying the
drag chute at high airspeed).  Every fighter pilot has extensive
training in spin recovery, and most have some practical experience
in spin recovery that they didn't expect :)

Toby Bradshaw
Department of Biochemistry and College of Forest Resources
University of Washington, Seattle
toby@u.washington.edu

"A well-educated electorate being necessary to the prosperity of
a free state, the right of the people to keep and read books, shall
not be infringed."  Do you conclude from this that only voters
may own books?



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