This method uses pre-defined trait thresholds to select best progenies. This method uses the selection index to select best progenies. This method selects only the top p-percent (where p is larger than 0 and smaller than 100) best progenies.This option is only available for univariate selection, i.e., either when one Scoring Code File only is specified in the Folder Containing Scoring Code Files option on the General tab or when multiple Scoring Code Files are specified and the option to Compute selection index is checked on the Analysis tab.
Make sure that Select best simulated progenies to cross option is checked.