Dear all
 
I found it prudent to enter this debate about genetic coefficient.  I
find it very alarming that some people think genetic coefficients are
dependent on the environment. More disturbing is the notion that they
are even model dependent.  I agree with Ajeet Singh Nain that this
coefficients are cultivar and species dependent only.  These
coefficients are as good as the experimental data from which they are
derived in the first place.  The degree days to Emergence, flowering and
maturity for a maize plant are dependent only on cultivar and are fairly
constant but for some random error.  Environmental factors are anly
modifiers for things like biomass and grain yield.   
 
I am open to further debate on this issue.
 
Dr. Emmanuel Xevi
CSIRO Land and Water
PMB 3
Griffith
Australia