>From: Jeffrey White <[log in to unmask]> >Reply-To: DSSAT - Crop Models and Applications <[log in to unmask]> >To: [log in to unmask] >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 <[log in to unmask]> >Sent by: DSSAT - Crop Models and Applications <[log in to unmask]> >01/28/2005 04:45 AM >Please respond to >DSSAT - Crop Models and Applications <[log in to unmask]> > > >To >[log in to unmask] >cc > >Subject >Winter wheat - cultivars for RSA > > > > > > >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 > >43 Sormany Rd, Brighton Beach, Durban, 4052 > >e-Mail: [log in to unmask] > >Mobile:  +27 (0) 82 4156136 > >Tel: +27 (0) 31 467 7114 > >Fax: +27 (0) 31 467 8203