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Native Maize Genetic Parameters Update

Deborah A Muenchrath mnchrath at iastate.edu
Wed Feb 17 10:22:14 EST 1999

Hello Michael,
Why are you going to GDD8?  To do this conversion, you will need to go back
to the original data and calculate the GDD for each day during the season
using the base temp of 8 C.   I can send you my raw data for the 92 and 93
field seasons if you really want to do that.  

Re info on the other cultivars, I suggest that you contact Mark Widrlechner
at the USDA-ARS Plant Introduction Stn here in Ames.  His phone number is
(515) 294-3255.  In 1992, I grew out 50 accessions, collected from the US
Southwest and northwestern Mexico.  The PI station (Peter Bretting) wanted
to gather some preliminary data on this cultivars, grown in an environment
more similar to their original than Ames Iowa.  The data collected included:
   Planting Date
   50% emergence date
   50% anthesis date
   50% silking date
You could calculated GDD between these points using the dissertation
weather info since they were grown in plots adjacent to the dissertation
field in 1992.  We only did this for 1 season.

I have the PI accession numbers of the cultivars examined.  I know at least
two of the lines were collected from Hopi.  I believe the others on your
list were included.  To get more specific detail on those accessions,  you
would need to contact Mark, who is the current acting research leader of
the station.  I did the grow-out in cooperation with Peter Bretting, the
then research leader who has since moved on to the main USDA office.  So, I
don't know what happened to the data.  If Mark (or Peter) don't have the
data analyzed or otherwise filed away and accessible, I could send you a
copy of the raw data (but you would still need to get the accession
identity info from the PI station).  The USDA-ARS GRIN system may also
provide you with some of the info that you want.  They have a website at:

The work  by Jesus Sanchez-Gonzalez would also probably be helpful.  Are
you familiar with his work?  He published several papers in Economic Botany
in the late 80s or early 90s.  Karen Adams and I have a paper in press in
JAS that details the morphological characteristics of Tohono maize
(Pima-Papago).  That paper will give you lots of info re kernel number and
weight (but there is tremendous vaiability!). 

I also have some data on Zuni blue and Zuni white maize. In collaboration
with others, we're studying the agroecosystem at Zuni.  That data is still
fresh and is just now being entered.  Offhand I don't recall the
relationship between Zuni maize and the cultivars you list.  (I believe
that Dobley had a paper, also in Economic Botany, that provided some info
on these relationships. 

Best wishes.  Let me know about your progress.  I'll be interested in
reading your work.


Deborah Muenchrath, Ph.D.
Adjunct Assistant Professor
Agronomy Dep.--Crop, Soil, and Environmental Sciences
Iowa State University
Ames IA 50011-1010

Tel:  (515) 294-7232
Fax: 515-294-8146
e-mail: mnchrath at iastate.edu

At 04:55 PM 2/16/99 -0600, you wrote:
>    I am still in the process of collecting maize genetic parameters to use
>with the CERES-Maize model in DSSAT 2.1.   As pointed in previous messages,
>DSSAT 3.5 would be better, but I am an aging graduate student with a
>limited budget; I can afford DSSAT 2.1 but not 3.5.  Does anyone have a
>copy they don't need and are willing to sell cheap?]  I can get some data
>from Deborah Muenchrath's dissertation on Tohono O'odham maize; however, I
>need to convert GDD10 to GDD8. I think I can convert the GDD but I will
>have figure out the total number of days.  Is there a simple formula or
>program to do this?
>    I have lost my Netscape address book and old emails.  If you have
>requested any information I have found out, please let me know again so
>I'll know who to send the information to.
>    I have done enough research to be more specific on the native maize
>varieties I am looking at.  The archaeological literature on prehistoric
>indicates that these varieties were similar to the following modern native
>varieties (most from northern Mexico):
>Mais de Ocho/Harinoso de Ocho
>Mais Blando
>Fremont Dent (?)
>Mexican Pyramidal (?)
>    So, I'll renew my request with these specific varieties in mind:
>Does anyone have or know where I can find or estimate the genetic
>parameters for the CERES-maize model for southwestern US aboriginal maize
>varieties?  Specifically, I need:
>Juvenile Phase: growing degree days (base 8 degrees C) from seedling
>emergence to end of juvenile phase (P1)
>Photoperiod: photoperiod sensitivity coefficient (P2)
>Grain-filling Duration: growing degree days (base 8 degrees C) from silking
>to physiological maturity (P5)
>Kernel Number: potential maximum kernel number per plant (G2)
>Kernel Weight:  potential kernel growth rate (mg/kernel per day) from
>silking to just before physiological maturity under optimal conditions (G3)
>Thanks for any help you can provide.
>Michael Pool
>mpool at austin.cc.tx.us
>Austin Community College
>Anthropology Department

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