Hi Matthias,

I guess genetic coefficients are even model specific.
A couple of months ago I used DSSAT and APSIM to model maize growth
(highland early white). Though the maize module of APSIM is based at least
partly on the early CERES-maize model and there is an overlap in the
different genetic coefficients that have to be defined, using the same
coefficients for both models didn't work out.
The original intention certainly was to create some "universal
coefficients", but then errors in the code are found, recalibration are
made, etc., confounding the original ideas a bit.
Only speaking about the maize genetic coefficients. It might be much more
straight forward in the other modules (soybean, peanut - Ken?)

Regards,
Rolf

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Rolf Sommer
CIMMYT (International Maize and Wheat Improvement Center)
Apdo. Postal 6-641, 06600 Mexico, D.F., Mexico
Tel. +52 (55) 5804 2004  Ext. 2128
Fax +52 (55) 5804 7558/59
www.cimmyt.org
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> -----Original Message-----
> From: Matthias Langensiepen [mailto:[log in to unmask]]
> Sent: Tuesday, February 03, 2004 06:30
> To: [log in to unmask]
> Subject: Re: Thank u _Clarification about Genetic Co.eff
>
> Dear All
> If it is true that genetic coefficients
> are cultivar but not environment specific,
> a corresponding calibration procedure
> would lead to the universal application
> of the model for each particular cultivar.
> There is experimental evidence that genetic
> coefficients become site and even
> season specific invalidating such
> an assumption. I would therefore
> strongly recommend to perform a thorough
> site-specific calibration in each new
> model application case following the
> procedures outlined in the DSSAT
> manuals.
>
> Matthias Langensiepen
> Modelling Plant Systems
> Institute of Crop Science
> Faculty of Agriculture and Horticulture
> Humboldt-University of Berlin
> Germany