Hellow Jeffrey
Thanks for information, it is really valuable.
Best wishes
Humaira
>From: Jeffrey White <
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>Reply-To: DSSAT - Crop Models and Applications <
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>To:
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>Subject: Re: Winter wheat - cultivars for RSA
>Date: Fri, 28 Jan 2005 08:26:19 -0700
>
>Hello Micheal,
>
>While I do not have genetic coefficients for the five wheat cultivars you
>list, I have a few comments that may be of interest to other modelers:
>
>1. There now are probably three versions of wheat models that run from
>DSSAT. For any request relating to specific crop or modeling issue, it
>will help to indicate the version being used. In the latest versions of
>DSSAT, the OVERVIEW.OUT file lists the model version in the header of each
>run. For example:
>*SIMULATION OVERVIEW FILE
>
>*DSSAT Cropping System Model Ver. 4.0.1.000 Jan 26, 2005;
>14:58:30
>
>2. Your e-mail subject line mentions "winter wheat." For southern
>Africa, aren't you actually growing wheats with a spring growth habit but
>planted in the fall/winter (May to July in the Southern Hemisphere)? This
>is a very common source of confusion. For initial modeling, you should
>definitely use a spring wheat cultivar with the vernalization and
>photoperiod requirements set low (but not necessarily to 0).
>
>3. One option for deducing cultivar coefficients might be through more
>widely known cultivars that are parents or sister lines of these
>cultivars. Unfortunately, of the five you list, the only cultivar whose
>pedigree I could find is Limpopo. The Global Wheat Information System
>shows Limpopo as having Tokwe as the paternal source, and Sonora 64 as one
>grandparent on the maternal side:
>http://mendel.lafs.uq.edu.au/cgi-bin/Germplasm.pl?name=limpopo
>
>4. Your very reasonable, practical query shows precisely why we need to
>push for a system that allows users to determine cultivar-specific
>coefficietns through actual crop genotypes. A typical spring bread wheat
>will have the dominant alleles at one to three of the Vrn1 loci. The line
>also may vary in earliness per se (Eps loci), dwarfing loci (Rht) and
>photoperiod (Ppd). The exact genotype of a given cultivar might be
>inferred from pedigree records or diagnosed with molecular probes
>(apparently available already for the Vrn and Rht loci). Markus Herndl
>posted a query on gene-based wheat models, and I would be curious to hear
>other people's ideas for wheat or any other crop.
>
>5. Do you have any data you can share or field performance? I would be
>glad to try to calibrate these for you. I do have limited data on Tokwe
>and Sonora 64 using DSSAT CSM 4.0
>
>Best regards,
>Jeff White
>
>USWCL, USDA-ARS
>Phoenix, AZ 85040
>Tel. 1-602-437-1702 x 268
>Fax 1-602-437-5291
>
>
>
>
>Micheal Howard <
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>Sent by: DSSAT - Crop Models and Applications <
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>01/28/2005 04:45 AM
>Please respond to
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>Subject
>Winter wheat - cultivars for RSA
>
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>
>Hi everybody,
>
>
>
>Could anyone please let me know if genetic coefficients for wheat
>cultivars like (Elands, Caledon,Gariep, Betta DN and Limpopo). This is
>for South Africa.
>
>Thanks
>
>Micheal Howard
>
>Agrista
>
>Visible communication.
>
>http://www.agrista.com
>
>PO Box 211165, Bluff, South Africa, 4036
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