Tutorials

DH Diallel Cross
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BMS 13.0-14.0 Tutorials

The doubled haploid (DH) lines planted in this study are considered promising for hybrid production. The genetic identity of the DH lines has been validated by genotyping with SNP markers (see previous tutorial). The purpose of designing and performing diallel crosses is to create hybrid seed for evaluation in a performance trial.

Design New Crosses

  • From the DH Lines study, select 'Design new crosses' from the 'Crossing options' of the Actions menu.

  • Select the 5 DH lines as parents for the crosses.

  • Right click the 5 DH lines. Add all five to the female list. Add all five to the male list.

  • Set the crossing method details appropriate for diallel crosses.
    - Cross each selected female with each selected male
    - Make reciprocal crosses
    - Exclude selfs

  • Generate Crosses. Continue after confirming the pending 20 crosses.

Create Hybrids in Database

Breeding Method

Breeding Method Note
Breeding methods punctuate generations in BMS pedigrees. Assigning a breeding method is a first step in the creation of new germplasm in the BMS. Crosses in the BMS are by default assumed to be generative breeding methods, where genetic diversity of offspring is expected to increase relative to parents. Breeding methods are used by the system to trigger different automatic naming conventions and inheritance of the management group ID (MGID) for fixed and hybrid germplasm.

 

  • Specify 'Hybrid Formation - VHY' as the generative breeding method for the cross. Continue.

Name Offspring

Automatic Naming Note
The BMS is preset with automatic naming conventions, but these can be customized for each breeding program. Automatic naming conventions are customizable via BMS database editing. Usually at the time of BMS installation an Integrated Breeding Platform data manager will set the automatic naming conventions to match needs of the breeding program. The option to 'Specify name format' is available via the browser interface. Choosing to 'Specify name format' will override the automatic naming conventions.

 

  • Choose to 'Specify name format'.
  • Set the cross code prefix 'Hyb19' to indicate via nomenclature that the germplasm is a hybrid created in 2019. (Keep in mind that it is not necessary to burden naming conventions with excessive detail, since the breeding method and date of creation will already be associated with the newly created germplasm)
  • Set the number of digits in the sequence number to 3.
  • Save the parentage designation as a string. This will facilitate future searches of all duplicate crosses.
  • Continue.

  • Finish.

  • Save the cross list.

Conclusion

After saving, the hybrids are created in the BMS database. The germplasm list is available to assist crossing and create labels for pollination bags and seed harvesting.  In later tutorials, we will generate the stock list and record harvest details.

  • Select the first hybrid to review the germplasm details.

The first hybrid in this germplasm list, Hyb19-001, is the result of the cross, DH-001/DH-002. Notice that SEED_SOURCE identifies the study, the location, and plot number of the female and male parents of the hybrids.
  • View the Pedigree Graph.

The first hybrid in this germplasm list, Hyb19-001, is assigned a GID and a management GROUP ID. Every time this cross is repeated in the future, the hybrid offspring will be assigned new GID, but will continue to be labeled with the GROUP ID, 6.

 

When crosses are made using the BMS, the pedigree is recorded automatically.