Hello Jin Yun,
 
Aloha! I am not very familiar with the potato model, but after a quick
look at it the genetic coefficients seem to be as follows:
     G2 - a leaf area expansion rate in degree days
     G3 - potential tuber growth rate
     G4 - does not seem to be used in the model
     PD - an index that supresses tuber growth during the period
          that immediately follows tuber induction
     P2 - an index that relates photoperiod response to tuber initiation
     TC - an upper critical temperature for tuber intitiation
 
To make GENCALC calculate genetic coefficients for potato, you will need
to add the following lines in the GCRULES.FLE file:
 
*PTSUB96 1  POTATO
5   P2           1/00*00    0.1    2.0   9   0.4    0.8       TUBER INDUC.
6   TC           1/00*00    0.5    2.0   9  15.0   22.0       TUBER INDUC.
1   G2           6/00*00   50.0  800.0   9 1800.  2200.       TUBER+TOP WT
2   G3           4/00*00    0.5  200.0   9  22.0   25.0       TUBER DRY WT
4   PD           4/00*00    0.1  100.0   9   0.7    1.0       TUBER DRY WT
 
*PTSUB96 2  POTATO
5   P2           1/00*00    0.1    2.0   9   0.4    0.8       TUBER INDUC.
6   TC           1/00*00    0.5    2.0   9  15.0   22.0       TUBER INDUC.
 
*PTSUB96 3  POTATO
1   G2           6/00*00   50.0  800.0   9 1800.  2200.       TUBER+TOP WT
2   G3           4/00*00    0.5  200.0   9  22.0   25.0       TUBER DRY WT
4   PD           4/00*00    0.1  100.0   9   0.7    1.0       TUBER DRY WT
 
You may manipulate the rules and the order of the rules.  You may want to
delete the rule that defines TC.  When I ran GENCALC on the data sets
in DSSAT, the value for TC always went to the minimum or maximum without
affecting the tuber induction date. This may be a result of air
temperature being near 15 C, nearly optimum for tuber initiation and the
lower limit for TC.
 
You will also need data for tuber dry weight, tuber + top dry weight, and
date of tuber induction in the averages file (*.PTA).
 
The last thing you will need is a new GENCON.EXE.  I will email this to
you.  The current GENCON.EXE cannot handle the very large genetic
coeffient G2.
 
If you have questions, please let me know ([log in to unmask]).
Good luck.
 
Sincerely,
Richard Ogoshi
 
 
On Mon, 14 Jul 1997, Jin-Il, Yun wrote:
 
> Hello,
>
> I am trying to find genetic coefficients of some potato cultivars in Korea
> using GenCalc.  There is neither explanation on G2, G3, G4, PD, P2, and TC
> of potato in DSSAT manual nor rules for potato in GCRULES file.  Is there
> any way to run GenCalc for potato?  I am using DSSAT version 3.0.
> Jin I. Yun, Ph.D
> Associate Professor, Agricultural Climatology
> Faculty of Life Science and Natural Resources
> Kyung Hee University
> Suwon 449-701,Korea
> Tel 82-331-280-2608
> Fax 82-331-281-4966
> e-mail : [log in to unmask]
>