Contents - Index
Biplot based on double-centered data
From Models select Centering, then Double-Centered.
This biplot is usually referred to as the AMMI2 biplot or GE biplot. It displays only the entry-by-tester interaction (GE).
Since entry and tester main effects have been removed, this biplot explains only the interaction GE. It is characterized by entries and testers falling in all directions. This biplot is most effective in displaying the GE patterns but cannot be used in selecting superior entries or testers. You have to use a GGE biplot (models 1- 3) for this purpose. That is, to select superior entries, the entry main effect G must be reconciled with the GE. This is a very important concept; its importance is manifested by the terms "GGE biplot" and the fact this software is called "GGEbiplot".
For example, the above biplot shows that tester 3 and entry 3 interacted positively. But this does NOT necessarily mean that entry 3 is the winner for tester 3. Verify this with the original data table: