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Select Best Variance-covariance Model

Select menu: Stats | QTLs (linkage/Association) | Phenotypic Analysis | Select Best Variance-Covariance Model for Multiple Environments

Use this to select the best variance-covariance matrix to model the genetic correlations between environments, based on the Schwarz (Bayes) Information Criterion (SIC or BIC) or Akaike Information Criterion (AIC). If data structures have been stored within the QTL data space then the names of the structures will be automatically entered in the relevant input fields.

  1. After you have imported your data, from the menu select
    Stats | QTLs (linkage/Association) | Phenotypic Analysis | Select Best Variance-Covariance Model for Multiple Environments.
  2. Fill in the fields as required then click Run.

You can set additional Options before running the analysis.

Available data

This lists data structures appropriate to the current input field. Double-click a name to copy it to the current input field or type the name. If data has been stored in a QTL data space then only the data structures present within that data space will be displayed in the Available data, otherwise all the current data within Genstat will be displayed. When data are present within the QTL data space you can right-click on the Available data list to open a shortcut menu where you can change between displaying data only within the data space and all data within Genstat.

Quantitative trait means

A variate specifying the quantitative trait means.

Genotype factor

A factor specifying the genotype for each mean.

Environment factor

A factor specifying the different environments.

Variance-covariance models

This lets you select one or more variance-covariance models that are to be compared for the set of environments. The output produced by this menu uses abbreviations for the different variance-covariance models. The table below details the descriptions and the abbreviations used in the output. For more details about the models see the VGESELECT procedure.

Description Abbreviation in output
Identity identity
Compound symmetry cs
Diagonal diagonal
Uniform covariances with unequal variances hcs
Uniform correlations with unequal variances outside
Factor analytic order 1 fa
Factor analytic order 2 fa2
Unstructured unstructured

Action buttons

Run Run the analysis.
Cancel Close the dialog without further changes.
Options Opens a dialog where additional options and settings can be specified.
Defaults Reset to the default settings. Clicking the right mouse on this button produces a shortcut menu where you can choose to set the options using the currently stored defaults or the Genstat default settings.

Action Icons

Pin Controls whether to keep the dialog open when you click Run. When the pin is down  the dialog will remain open, otherwise when the pin is up  the dialog will close.
Restore Restore names into edit fields and default settings.
Clear Clear all fields and list boxes.
Help Open the Help topic for this dialog.

See also

Updated on April 24, 2019

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