Validation of using EC mapping to account for site variability in the early stages of selection in the Sugar Research Australia breeding program

Previously in a clonal assessment trial (CAT), four zones identified by EC mapping produced significantly different yields. If ignored, these differences would result in different and biased selection intensity in the different zones, that is, fewer clones would be selected from a low-yielding zone. However, these differences could be caused by different sets of clones in each zone (despite low possibility given the random distribution of clones over the trial) and the clones from a low-yielding zone could actually be poor in the next stage of selection, the final assessment trial (FAT, with higher precision). Here, the yields in different zones were confirmed to be significantly different when a single variety Q208A was grown in the exact same site as the CAT. The clones selected from a low-yielding zone at the CAT stage did not produce significantly different yields to those from high-yielding zones in FATs. This reinforces our conclusion from the previous study that EC mapping is an effective tool in accounting for site variability in sugarcane selection programs.